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Simulation and Analysis of Wireless Mesh Network in Smart Grid – Advanced Metering Infrastructure by Philip Huu Huynh B.A., The University of Economics, Vietnam, 1996. A thesis submitted to the Faculty of Graduate School of the University of Colorado at Colorado Springs in partial fulfillment of the requirements for the degree of Master of Science Department of Computer Science 2011 ii Thesis for the Master of Science degree by Philip Huu Huynh has been approved for the Department of Computer Science by _______________________________________________________ Advisor: Dr. C. Edward Chow _______________________________________________________ Dr. Jugal K. Kalita _______________________________________________________ Dr. Rory Lewis _____________________ Date iii Simulation and Analysis of Wireless Mesh Network in Smart Grid – Advanced Metering Infrastructure by Philip Huu Huynh Master of Science, Computer Science Thesis directed by Associate Dean Professor C. Edward Chow Department of Computer Science Abstract In this thesis the use of Wireless Mesh Network (WMN) technologies as the Advanced Metering Infrastructure (AMI) for the collecting of meter data in real-time was proposed and analyzed. A Google Maps mashup was developed to display the locations of the meters and light poles, which can be selected for mounting the WiMAX or Wi-Fi network devices. A NS-3 simulator was developed to simulate the network traffic of meter data collection over the WMN and to allow us evaluating different topologies and to see if their capacities are adequate to report all meter values to the data center within one second. A JavaScript program was developed to analyze the meter density within different service areas of Colorado Springs Utilities. The information can be used for antennae placement planning. We proposed a hybrid WiMAX and Wi-Fi mesh network to address the cost and efficiency issues. In local service area, we can use lower cost Wi-Fi mesh network to iv connect smart meters to the WiMAX Base Stations. From those WiMAX Base Stations, we utilize the long distance links provided by WiMAX point-to-point connection mode to collect meters from local service areas to a handful of take out points. From take-out points, high speed optical fiber connections are to be used transport the meter data to the data center. We evaluate the design trade offs of these WMN choices through the NS-3 simulations. The simulation results show that with this type of WMN (6 WiMAX Base Stations and 540 Wi-Fi Access Points), it is feasible to collect meter data from 150,000 smart meters within one second. The Smart Grid Wireless Infrastructure Planning (SG-WIP) Google Maps mashup tool can be integrated with the simulator and allow the planner to interactively adjust the planning of wireless network devices such as WiMAX Base Stations, or Wi-Fi Access Points on the light poles in certain service areas. v Acknowledgments This thesis could not have been accomplished without the assistance of many people whose contributions I gratefully acknowledge. First, I am heartily thankful to my advisor, Dr. C. Edward Chow, whose encouragement, guidance and support from the initial to the final level enabled me to develop an understanding of the subject. I would like to thank Dr. Jugal K. Kalita and Dr. Rory Lewis, for their support during the thesis development. The value and contribution of this thesis has been increased very much by their helps. Many thanks to my friends, the NS-3 community, the Google Maps development community, the Professors and Staff in the Computer Science department for helping me finish this thesis. I would like to thank the Management of Colorado Springs Utilities, for their support to improve the possibility of practical application of this thesis. Finally, I would like to show my gratitude to my parents for bringing me here a wonderful place for learning and development. vi Table of Contents Chapter 1 Introduction .........................................................................................................1 1.1 Thesis Statement .......................................................................................................2 1.2 Thesis Goals ..............................................................................................................2 1.3 Thesis Contributions .................................................................................................3 Chapter 2 Background and Related Works .........................................................................4 2.1 Introduction to Smart Grid - Advanced Metering Infrastructure ..............................4 2.1.1 Growing the need for the Smart Grid (SG) .........................................................4 2.1.2 Growing the need for the Smart Grid (SG) .........................................................6 2.2 Introduction to Wireless Mesh Network ...................................................................8 2.2.1 What is the Wireless Mesh Network (WMN)? ...................................................8 2.2.2 Wireless Mesh Network - The wireless infrastructure solution for AMI .........10 2.3 Related Works .........................................................................................................11 2.3.1 Colorado Springs Utility AMI Wireless Infrastructure ....................................11 2.3.2 SkyPilot Synchronous Mesh Network Solution ...............................................11 2.3.3 EkaNetTM Smart Network – Wireless Mesh Network Solution .......................13 2.3.4 Coverage and Capacity of A Wireless Mesh Network, by H.Huang, et al ......15 2.4 Research Opportunities ...........................................................................................16 2.5 Summary ..................................................................................................................17 Chapter 3 Problem and Solution .......................................................................................18 3.1 Problem Statement ..................................................................................................18 3.2 Approach .................................................................................................................18 3.2.1 Develop a Network Model for Communication Infrastructure ........................18 3.2.2 Simulate the AMI meter data reporting process ...............................................19 3.2.3 Analyze the Simulation Results ........................................................................20 3.3 Summary ..................................................................................................................20 vii Chapter 4 Planning and Implementing the Network Simulation .......................................22 4.1 Introduction to the Smart Grid Wireless Infrastructure Planning (SG-WIP) ...........22 4.2 Planning the Network Simulation ............................................................................26 4.3 Design the Network Simulation ...............................................................................27 4.3.1 Physical Network Model ...................................................................................27 4.3.1.1 The Hybrid WMN Architecture ..................................................................27 4.3.1.2 The WiMAX/Wi-Fi Network Infrastructure ...............................................29 4.3.1.3 An Overview of the NS-3 WiMAX Module ...............................................32 4.3.1.4 An Overview of the NS-3 Wi-Fi Module ....................................................36 4.3.2 The Application Model ......................................................................................38 4.3.2.1 The Client-Server Architecture ...................................................................38 4.3.2.2 The Generation of Meter Data Traffic ........................................................39 4.3.2.3 The NS-3 Server Application ......................................................................39 4.3.2.4 The NS-3 Client Application .......................................................................39 4.3.3 The WLAN Simulation Design .........................................................................39 4.3.3.1 Results Analysis and Conclusion ................................................................40 4.3.3.2 Results Analysis and Conclusion ................................................................40 4.3.3.3 Results Analysis and Conclusion ................................................................40 4.3.3.4 Results Analysis and Conclusion ................................................................40 4.3.4 The WNAN Simulation Design .........................................................................40 4.3.4.1 Topology Configuration ..............................................................................40 4.3.4.2 Application Configuration ...........................................................................41 4.3.4.3 Simulation Planning ....................................................................................41 4.3.4.4 Results Analysis and Conclusion ................................................................41 4.3.5 The WMAN Simulation Design ........................................................................42 4.3.5.1 Topology Configuration ..............................................................................42 4.3.5.2 Application Configuration ...........................................................................42 4.3.5.3 Simulation Planning ....................................................................................42 4.3.5.4 Results Analysis and Conclusion ................................................................42 4.3.6 The WAN Simulation Design............................................................................43 4.3.6.1 Topology Configuration ..............................................................................43 viii 4.3.6.2 Application Configuration ...........................................................................43 4.3.6.3 Simulation Planning ....................................................................................43 4.3.6.4 Results Analysis and Conclusion ................................................................43 4.4 Implementing the Network Simulation ....................................................................44 4.4.1 The WLAN Simulation .....................................................................................44 4.4.1.1 The NS-3 Script ...........................................................................................44 4.4.1.2 The Linux Shell Script ................................................................................45 4.4.2 The WNAN Simulation .....................................................................................45 4.4.2.1 The NS-3 Script ...........................................................................................45 4.4.2.2 The Linux Shell Script ................................................................................46 4.4.3 The WMAN Simulation ....................................................................................47 4.4.3.1 The NS-3 Script ...........................................................................................47 4.4.3.2 The Linux Shell Script ................................................................................48 4.4.4 The WAN Simulation ........................................................................................48 4.4.4.1 The NS-3 Script ...........................................................................................48 4.4.4.2 The Linux Shell Script ................................................................................49 Chapter 5 Simulation Results and Analysis .......................................................................50 5.1 The Simulation Experiments ....................................................................................50 5.1.1 The WLAN Simulation Experiment ..................................................................50 5.1.2 The WNAN Simulation Experiment .................................................................51 5.1.3 The WMAN Simulation Experiment .................................................................51 5.1.4 The WAN Simulation Experiment ....................................................................53 5.2 Simulation Results Data Collection .........................................................................53 5.3 The Simulation Results ............................................................................................54 5.3.1 The WLAN Simulation Results ....................................................................54 5.3.1.1 Experiment 1: WLAN topology with 50 SMs.............................................54 5.3.1.2 Summary of the WLAN Simulation Experiments ......................................55 5.3.2 The WNAN Simulation Results ....................................................................55 5.3.2.1 Experiment 1: The WNAN topology with 9 APs........................................56 5.3.2.2 Summary of the WNAN Simulation Experiments ......................................59 5.3.3 The WMAN Simulation Results........................................................................59 ix 5.3.3.1 Experiment 1: The WMAN topology with 10 GWs ...................................60 5.3.3.2 Summary of the WMAN Simulation Experiments .....................................61 5.3.3.3 Summary of the Experiments for WMAN Improved Design ....................61 5.3.4 The WAN Simulation Results ...........................................................................62 5.3.4.1 Experiment 1: The WAN Star Topology With 3 BSs ................................62 5.3.4.2 Summary of the Experiments for the WAN Improved Design ...................64 5.4 Simulation Results Analysis ....................................................................................65 5.4.1 The WLAN Simulation Results Analysis ..........................................................65 5.4.2 The WNAN Simulation Results Analysis .........................................................67 5.4.3 The WMAN Simulation Results Analysis.........................................................69 5.4.4 The WAN Simulation Results Analysis ............................................................72 Chapter 6 Lessons Learned ................................................................................................77 6.1 The Development of SG-WIP Planning Tool ..........................................................77 6.2 The Development of Smart Grid Simulation Model ................................................78 6.3 The Simulation Process in NS-3 ..............................................................................79 6.3.1 The Initialization Phase of Wireless Networks .................................................79 6.3.2 The Bugs in NS-3 Module Code .......................................................................79 Chapter 7 Simulation Limitations and Future Work..........................................................81 7.1 Display Simulation Results on the SG-WIP Planning Tool .....................................81 7.2 Alternative Method for Network Traffic Application Simulation ...........................82 7.3 Improve the Antennae Placement Algorithm ..........................................................82 7.4 Store the Real-time Meter Data in the Database Management System (DBMS) ....83 7.5 Evaluate the Performance of the Network Model with the AMI real-time..............83 Chapter 8 Conclusion .........................................................................................................84 Bibliography ......................................................................................................................86 Appendix A SG-WIP User Manual ...................................................................................90 A.1 Installation ...............................................................................................................90 A.1.1 System Requirements .......................................................................................90 A.1.2 The Database ....................................................................................................90 A.1.3 The SG-WIP Application .................................................................................90 A.2 The GUI Operations ................................................................................................92 x A.2.1 Opening the Home page ...................................................................................92 A.2.2 Generating the WAN Topology........................................................................93 A.2.3 Generating the MAN Topology ........................................................................94 A.2.4 Generating the NAN Topology ....................................................................95 A.2.5 Generating the LAN Topology .........................................................................96 A.2.6 Changing the Antennae Location of Network Devices ....................................97 Appendix B SG-SIM Smart Grid Simulator Running Examples ......................................98 B.1 The LAN Simulation Examples ..............................................................................98 B.2 The NAN Simulation Examples ............................................................................100 B.3 The MAN Simulation Examples ...........................................................................104 B.4 The WAN Simulation Examples ...........................................................................107 xi List of Tables Table 4.1 - The ranges of housing unit density of the LAN, NAN, MAN topologies in Colorado Springs. ..............................................................................................................24 Table 5.2 - The WLAN simulation results with 50 SMs. The statistical data are in one second period. ....................................................................................................................55 Table 5.3 - The results of WLAN simulations with different number of SMs. The statistical data in each row are the results of one simulation experiment .........................55 Table 5.4 - The simulation results for WNAN 3x3 grid topology with nine APs. The statistical data are in one second period. ....................................................................58 Table 5.5 – The results of WNAN simulation. The statistical data in each row are the results of one simulation experiment .................................................................................59 Table 5.6 – The simulation results for WMAN Point-to-multipoint topology with ten GWs. The statistical data are in one second period. ..........................................................61 Table 5.7 – The WMAN simulation results. The statistical data in each row are the results of one simulation experiment............................................................................................61 Table 5.8 - The simulation results of a WMAN topologies experiment that has 10 gateways. The number of meter data packets put in a sending UDP packet was changed until the UDP packet is fragmented. ..................................................................................62 Table 5.9 – The simulation results of a WAN Point-to-point Star topology with three base stations. The statistical data are in one second period .......................................................63 Table 5.10 – The WAN simulation results. The statistical data in each row are the results of one simulation experiment............................................................................................64 Table 5.11 - The of simulation results of the WAN topologies experiments that have one base station connected to the data center. The length of the optical fiber cable was changed to evaluate the total processing delay at a BS .....................................................64 xii List of Figures Figure 2.1 - Smart grid overview (source: U.S. Department of Energy) .............................5 Figure 2.2 - Smart Grid Conceptual Framework (source: The National Institute of Standards and Technology) ..................................................................................................6 Figure 2.3 - AMI overview (source: National Energy Technology Laboratory) .................7 Figure 2.4 – AMI enabled integrated utilities operations (source: California Energy Commission Meter Scoping Study) ..................................................................................8 Figure 2.5 -IEEE 802.11s terms: A Mesh Portal (MPP) connects to the wired Internet, a Mesh Point (MP) just forwards mesh traffic, and a Mesh Access Point (MAP) additionally allows stations (STA) to associate with it ........................................................9 Figure 2.6 - A SkyExtender was installed on the street light pole (source: SkyPilot) .......12 Figure 2.7 - SkyPilot Mesh Network Architecture (source: SkyPilot) ..............................12 Figure 2.8 - EkaNet Smart Network Architecture for AMI ...............................................14 Figure 2.9 - Mesh cell architecture for the outdoor applications .......................................16 Figure 4.1 – The SG-WIP tool for planning AMI wireless infrastructure network in Colorado Springs ...............................................................................................................23 Figure 4.2 - Using SG-WIP tool for planning the antennae position. The WiMAX/Wi-Fi gateway was place on streetlight pole ................................................................................24 Figure 4.3 - The WLAN topology (100x100 square meters) has a high density of resident housing units ......................................................................................................................25 Figure 4.4 - WiMAX as backhaul inter Wi-Fi mesh networks (source: Intel) ..................29 Figure 4.5 - Logical view of the WM Communication Network includes the first three layers of the OSI model ............................................................................................30 Figure 4.6 - Physical model of the WM Communication Network. The network hierarchy includes the Wi-Fi Mesh Routers, the WiMAX/Wi-Fi Gateways, and the WiMAX BS ..31 xiii Figure 4.7 - NS-3 WiMAX protocol stack overview .........................................................36 Figure 4.8 - NS-3 Wi-Fi layer 2 stack overview ................................................................38 Figure 4.9 - Smart meters access the Meter data center through the Wireless mesh communication network.....................................................................................................39 Figure 5.1 - The simulation results in every one second for the WLAN Infrastructure mode topology with one AP and fifty SMs in the network. .............................................65 Figure 5.2 - The simulation results for the WLAN infrastructure mode topology. The number of SMs is assigned from the one to one hundred in the experiments to evaluate the changing of the total processing delay at the SMs. ......................................................66 Figure 5.3 - The simulation results in every one second for the WNAN 3x3 mesh topology with nine APs and one GW. AP sent 50 packets in every one second to the GW. ............................................................................................................................................67 Figure 5.4 - The simulation results of the WNAN 3x3 grid topology with nine MRs and one GW in the network ......................................................................................................68 Figure 5.5 - The simulation results of WMAN point-to-multipoint topology with one BS and ten GWs in the network. GW sent 180 packets in every one second to the BS ..........69 Figure 5.6 - The simulation results for the WMAN topology. The number of GWs are assigned from the one to ten in the experiments to evaluate the changing of total processing delay at the GWs ..............................................................................................70 Figure 5.7 - Impact on the network performance by aggregating meter data ....................71 Figure 5.8 - The simulation results in every one second for the WAN star topology with DC and three BSs in the network. BS sent 1,800 packets in every one second to the DC 73 Figure 5.9 - The simulation results for the WAN star topology from many experiments .74 Figure 5.10 - The simulation results for the WAN star topology with one DC and one BS. The length of the optical fiber cable was assigned from the one to 100 kilometers ..75 Figure A.1 - The SG-WIP application was installed on the Apache web server ...............91 Figure A.2 - The home page of SG-WIP ...........................................................................92 Figure A.3 - The WAN topology has twelve WiMAX base stations ................................93 Figure A.4 - The WMAN topology has WiMAX BS, and WiMAX/Wi-Fi Gateways .....94 xiv Figure A.5 - The WNAN topology has WiMAX/Wi-Fi gateway, and Mesh routers/Access Points .........................................................................................................95 Figure A.6 - The WLAN topology includes Wi-Fi Access Point, and Smart meters ........96 Chapter 1 Introduction Recently many utilities started to deploy smart grids for collecting meter data [DoE01, NETL08]. The main reasons are to reduce the cost by not sending people to read the meter data and by avoiding generating excess power through correct prediction of the load profile using the aggregated meter values. To correctly predict the load profile and perform load forecasting, utilities need to collect meter data in real time. Utilities have hundreds of thousands of meters installed in their service areas, and want to network these meters for metering collection. The wireless communication technologies have been popularly deployed in the local areas and the metropolitan areas because of their conveniences in the cost, network installation and maintenance. Taking advantages of the wireless technologies, utilities can network their meters and the data center for data communication. However, if the underlined wireless technologies do not provide enough bandwidth, then the meter data cannot be delivered to the data center in time. The WiMAX technology allows us networking the meters and the data center with the broadband data transmission at long distance and higher bandwidth [IEEE16, ZR06]. 2 Therefore, the wireless networking solution for real-time metering collection is feasible. The important question is to design of the wireless infrastructure and their topology so that it can be scaled up and meet the cost and real-time performance requirements, given huge wireless meters to be served in large areas. For example, The Wi-Fi mesh technology can be employed as part of a hybrid wireless infrastructure with WiMAX and Wi-Fi to allow the deployment at the reasonable low cost [AWW05, INTL04]. The wireless technologies such as WiMAX, and Wi-Fi are high performance, scalable, and secured [AWW05]. Taking the advantages of these network technologies, utilities can deploy the smart grid wireless communications infrastructure for the real-time metering collection. The real-time meter data can save the operation costs and reduce the electricity market price. 1.1 Thesis Statement In this thesis we plan to address the following important question: Is the wireless mesh network infrastructure applicable for the real-time meter data collection? It is a challenge facing the smart grid wireless infrastructure planners. We intend to conduct a simulation analysis of the wireless communication infrastructure for the smart grid to answer this question. 1.2 Thesis Goals In this thesis, we propose to research and develop a wireless communication infrastructure solution using the wireless mesh network technologies for the smart grid. Tools and techniques will be developed for the planning and designing the wireless infrastructure. The performance and scalability properties of the proposed wireless 3 infrastructure are evaluated. We focus on these network properties because they are the important factors that affect the performance of the real-time meter data collection. 1.3 Thesis Contributions This thesis will contribute to the smart grid research by investigating the wireless mesh network that is employed as a communication infrastructure solution for the real-time metering collection. The wireless infrastructure planning tools in this thesis will benefit not only the researchers but also the utilities. The network infrastructure planners and researchers can use the planning tools to conduct surveys about wireless network topologies. Moreover, the infrastructure planners and designers can use the tools to refine their network designs. Another contribution of this thesis is to provide a communication network solution that is low cost, and secured. It allows the utilities to have an alternative option for their AMI wireless infrastructure. The proposed wireless infrastructure with the wireless mesh technologies are cheap, far-reaching, and scalable. Chapter 2 Background and Related Works 2.1 Introduction to Smart Grid - Advanced Metering Infrastructure 2.1.1 Growing the need for the Smart Grid (SG) A smart grid [DoE01, DoE02, Wiki01] delivers electricity from suppliers to consumers using two-way digital communication technology. Smart grid allows controlling appliances at consumer’s homes to save energy, and reduce cost. The operation status of the smart grids can be monitored in real time, so the smart grids are more reliable. Many governments are promoting such a modernized electricity network as a way of addressing energy independence, global warming and emergency resilience issues. 5 Figure 2.10 - Smart grid overview (source: U.S. Department of Energy) Figure 2.1 shows an overview of the smart grid. Utilities can archive energy efficiency and maintain the competitive of services by taking advantages of the smart grid and its market benefits. The smart grid solutions that utilize the information technology for data collection, monitoring and control, data analysis and information communication infrastructure, will cost-effectively protect revenues today, while laying the foundations for future services. Figure 2.2 shows the conceptual framework of smart grid. The components include Service Provider, Operations, Markets, Bulk Generation, Transmission, Distribution, and Customer. 6 Figure 2.11 - Smart Grid Conceptual Framework (source: The National Institute of Standards and Technology) 2.1.2 Advanced Metering Infrastructure (AMI) Advanced Metering Infrastructure (AMI) [NETL08] that is as part of larger Smart Grid initiatives, is implemented by government agencies and utilities to meet the above challenges. Extending from the current Automatic Meter Reading (AMR) technology, AMI provides two way meter communications, and allows commands to be sent toward the home for multi purposes, including Time-of-Use pricing information, demandresponse actions, or remote service disconnects. 7 Figure 2.12 - AMI overview (source: National Energy Technology Laboratory) The Department of Energy estimates that over 280 Giga-watts of new generating capacity will be needed by 2025. It results in new power plants would be built in the future. The energy industry is facing the critical issues such as the need for new plants, maintaining overburdened infrastructure, coping with an aging workforce, complying with regulations, and environmental concerns. For a long time, the energy industry has rightfully focused on the supply side of this challenge. But now, the demand side of the equation can be significantly impacted by the existing of the wireless mesh networking [Kri01]. 8 Figure 2.13 - AMI enabled integrated utilities operations (source: California Energy Commission Meter Scoping Study) Wireless mesh networking can use as the backbone of the AMI solutions to enable twoway intelligent networked communications with smart meters. With the AMI, the value added services such as demand response and demand side management would be enabled, besides meter reading. AMI solutions allows interoperable networks and systems across the entire power structure aid in the management and control of energy consumption, improve operations management, conserve the environment, and adhere to evolving regulations [NETL08]. 2.2 Introduction to Wireless Mesh Network 2.2.1 What is the Wireless Mesh Network (WMN)? 9 A WMN [IEEE11s, Moh01] is a communications network made up of radio nodes organized in a mesh topology. Wireless mesh networks often consist of mesh clients, mesh routers and gateways. The mesh clients are often laptops, cell phones and other wireless devices while the mesh routers forward traffic to and from the gateways which may but need not connect to the Internet. A mesh network is reliable and offers redundancy. When one node can no longer operate, the rest of the nodes can still communicate with each other, directly or through one or more intermediate nodes. Wireless mesh networks can be implemented with various wireless technology including IEEE 802.11, IEEE 802.15, and IEEE 802.16 [IEEE11, IEEE15, IEEE16] , cellular technologies or combinations of more than one type. Figure 2.14 - IEEE 802.11s terms: A Mesh Portal (MPP) connects to the wired Internet, a Mesh Point (MP) just forwards mesh traffic, and a Mesh Access Point (MAP) additionally allows stations (STA) to associate with it 10 2.2.2 Wireless Mesh Network - The wireless infrastructure solution for AMI When the WMN technology is applied in AMI solutions, it can bring new components to the electrical grids, such as self-managing and self-healing mesh networking, intelligent meters, and bridging to Home Area Networks (HAN) [NETL08] for connectivity with energy consuming appliances. The real time communication between the smart meters and the utility’s data center provides detailed usage data while also receives and display Time-of-Use (TOU) pricing information, and offers other on-demand abilities such as remote connect or disconnect, unrestricted monitoring and control, etc. Customers are able to access the usage data for tailoring consumption and minimizing energy expenses while helping balance overall network demand. When WMNs are used in the AMI, they can provide the following features [LLT03, Kri01]: Low cost of management and maintenance - WMNs are self-organizing and require no manual address/route/channel assignments. It is simple to manage thousands or millions of devices resulting in the lowest total cost of ownership. Increased reliability – The WMN routing mechanisms provide the redundant paths between the sender and receiver of the wireless connection. Communication reliability is significantly increased because of the eliminations of single point failures and potential bottleneck links. Network robustness against potential problems, e.g., node failures and path failures due to RF interferences or obstacles, can also be ensured by the existence of multiple possible alternative routes. 11 Scalability, flexibility and lower costs - WMNs are self-organizing and allow true scalability. Nodes and Gateways are easily added at a very low cost with: o No limitation on number of hops o No network address configuration o No managed hierarchical architecture o No hard limitation on number of Nodes per Gateway Robust security – WMNs have the security standards that allows all communications in AMI are protected by mutual device authentication and derived per-session keys using high bit rate AES encryption. This hardened security approach allows for authentication as well as confidentiality and integrity protection in each communication exchange between every pair of network devices – Smart meters, Relays, or Wireless Gateways. 2.3 Related Works 2.3.1 Colorado Springs Utility AMI Wireless Infrastructure The Colorado Springs Utility AMI wireless network infrastructure used the Point-toMulti Point topology where 902-928MHz concentrators are used to collect meter data in a neighbor area mounting on the light pole, eight take-out points are used to poll and collect meter data from hundreds of concentrators. Telecommunication links and fiber connections are used to connect take-out points to the data center. The current meter data reading interval is five minutes for electric, fifteen minutes for gas and water meters [Chow09]. 12 2.3.2 SkyPilot Synchronous Mesh Network Solution MetroFi has deployed a mesh network in the Silicon Valley – California [Met01]. The installed wireless mesh metropolitan area network can provide the Internet access service to the resident user in a geographical area that covers about 250,000 households. The SkyPilot’s Synchronous Mesh Network solution was employed to build this mesh network. The SkyPilot’s mesh network solution combines standard-based Wi-Fi access with a high performance wireless mesh backhaul network using SkyGate nodes to interface with the Internet, SkyExtender DualBand nodes that integrate Wi-Fi access and mesh backhaul [Sky01]. Figure 2.15 - A SkyExtender was installed on the street Figure 2.16 - SkyPilot Mesh Network Architecture (source: SkyPilot) light pole (source: SkyPilot) The mesh network MetroFi is a success deployment of the WMN onto the large geographical area. However, in the AMI meter data collection application, there is a different in the network traffic pattern compared to the regular Web applications. The 13 Web applications usually need the connection with low bandwidth uplink, and high bandwidth downlink. In contrast, the AMI meter data reporting process requires the high bandwidth uplink connections to send the data from smart meters to data center. We can make an assumption that we intend to use the MetroFi network for the AMI communication infrastructure solution. Then, there is a research opportunity about the MetroFi or WMN performance – Whether the WMN is suitable for the AMI network infrastructure, especially for the real-time meter data reporting application? 2.3.3 EkaNet™ Smart Network - Wireless mesh network solution for Smart Grid/AMI The wireless mesh infrastructure EkaNet [Eka01] includes the smart meter nodes, ranger extension nodes, and gateway nodes. The smart meter nodes are networking together to form the wireless mesh network. It means that, the communication between a smart meter node and the gateway will replay on a number of other smart meters. The range extension nodes are used to help connect the out of coverage nodes. The gateway nodes provide the interface to the Internet network. Figure 2.17 - EkaNet Smart Network Architecture for AMI 14 The EkaNet has been deployed in some world wide areas such as Guayaquil - Ecuador, St. Petersburg – Russia. In Guayaquil – Ecuador, the utility has installed 3,614 wireless meter nodes, 314 repeaters, and 47 gateways. Meter data collection interval period is fifteen minutes. The Advantages Wireless mesh network provides a low cost, easy deployment and management, scalable, flexible The Disadvantages The number of relay hops will increases with the increasing number of the smart meters. As a result, the network performance will go down fast, especially in the service place where the smart meter density is high, i.e. hundreds of smart meters in the area 100 meters by 100 meters. In the high resident density area, the mesh topology will not be a good choice for the network performance goal. Instead, the point-to-multipoint topology such as Wi-Fi infrastructure mode would provide a better network performance. 2.3.4 Research Paper “Wireless Mesh Networks: A Survey” [AWW05] The authors conducted a survey about the current research and development of WMN technologies (2005). The author presented many open research issues needed to be solved such as scalability, self-organization and self-configuration, security, network integration. 15 The critical factors influencing protocol design were discussed for improvement objectives. 2.3.5 Research Paper “The Nominal Capacity of Wireless Mesh Networks” [JS03] This article tackles the problem of determining the exact capacity of a WMN. The concept of bottleneck collision domain was introduced to enable this calculation. The authors shown that for WMNs the throughput of each node decreases as O(1/n), where n is total number of nodes in the network. Moreover, for a given topology and the set of active nodes, the upper bounds on the throughput of any node can be exactly calculated. 2.3.6 Research Paper “Capacity of Grid-Oriented Wireless Mesh Networks” [ANMK08] The author presented an analytical framework for determining the nominal capacity of multi-radio multi-channel Wireless Mesh Network (WMN). The concept of collision domain was derived to calculate an upper bound on the capacity available to ingress nodes that generate traffic towards the node that acts as the gateway to the outside world. As the research conclusion, the effects of WMN design parameters such as network topology, network size, routing methods, channel assignment schemes etc. are interlinked and a judicious selection is essential to maximize capacity. 2.3.7 Research Paper “Architecture and Algorithms for an IEEE 802.11-based Multi-channel Wireless Mesh Network” [RC05] 16 The author proposed a novel multi-channel WMN architecture that effectively addresses the bandwidth problem by fully exploiting non-overlapped radio channels that the IEEE 802.11 standards make available. Two fundamental design issues in the proposed multichannel WMN architecture are solved. The first one is about the determining which of the available non-overlapped radio channels should be assigned to each 802.11 interface in the WMN. The second issue is how packets should be routed through a multi-channel WMN. 2.3.8 Research Paper “Multi-Channel Mesh Networks: Challenges and Protocols” [KSCV06] The authors considered the use of multi-channel to improve the throughput of Wireless Mesh Network (WMN). The main challenges were highlighted and two link-layer protocols were presented for utilizing multiple channels. A new abstraction layer that simplifies the implementation of new multi-channel protocols in existing operating systems was presented. 2.3.9 Research Paper “Coverage and capacity of a wireless mesh network” [HWC05] The authors proposed a scalable multi-channel ring-based WMN architecture and developed an analytical framework to evaluate the capacity and coverage of such a network. An optimization approach to maximize capacity and coverage for the considered WMN has been also presented. 2.3.10 Research Paper “The IEEE 802.11s Extended Service Set Mesh Networking Standard” [CK08] 17 The author presented how the developing IEEE 802.11s ESS Mesh Networking Standard draft addresses technical challenges of the pervasive development of wireless mesh networks (WMNs), the efficient allocation of mesh resources (routing and MAC layers), the protection of network resources (security and power savings), and the elimination of spatial bias (congestion control). Many examples from existing two-tier developments, simulations, and analytical models are used to motivate these enhancements within the standard. 2.3.11 Research Paper “An Improved IEEE 802.16 WiMAX Module for the ns-3 Simulator” [IPGT10] The authors presented the new features and enhancements that were integrated within the ns-3 WiMAX module. The new design of the physical layer has improved the simulation time by several magnitude orders while still providing a realistic implementation of the standard. The IP classifier has enabled the simulation of an unlimited number of service flows per subscriber station, while the proposed schedulers improve the management of the QoS requirements for the different service flows. These proposed features can make easier and more realistic the evaluation and design of WiMAX systems. 2.4 Research Opportunities This thesis discusses about the evaluation of performance of the WMN when it is employed as the wireless infrastructure solution for the AMI real-time metering data collection application. The related work has proved that the WMN can be used in the networking solutions that require the deployment onto large geographical areas, such as the AMI communication 18 infrastructure. However, the WMN infrastructure needs a high bandwidth for transmitting the meter data from the smart meters to the data center in real-time. The conducted researches have shown that the WMN network bandwidth is affected many network design parameters such as network the topology, network size, routing protocols, multichannel assignment scheme [ANMK08, RC05, KSCV06]. In particularly, the more hop number is the WMN routing path, the less performance is the WMN [LLT03, ZR06, HWC08]. 2.5 Summary In general, the wireless mesh network infrastructure can provides a cheap solution, compared to the wire network, connecting the smart meters to the utility data center. However, to answer the challenge question, whether the wireless mesh infrastructure is suitable for the real-time meter data reporting process, this thesis will go into more detail in the analysis of the performance property of the wireless network infrastructure solution. We will develop new tools and techniques to assist the planning and design phase. We will also use the network simulation method to evaluate the network performance. Chapter 3 Problem and Solution 3.1 Problem Statement The WMN contributes many advantages to the AMI Communication Network solution. However, there are challenge questions in planning, designing and deployment of WMN. • Does the WMN meet the network performance requirements for real-time Meter Data Collection? • What is the trade-off between the Performance and Scalability, for cost optimization? This thesis will answer these challenge questions by using simulation method. 3.2 Approach 3.2.1 Develop a Network Model for Communication Network 20 For the network researching, planning and designing, we will develop and implement a network topology planning application. The application can assist the network planning and design phase, for example the planning of antennae placement of the wireless devices, or research the network traffic based on the smart meters density in the service areas. For the simulation of AMI real-time meter data reporting application, we will develop a hybrid WMN model for AMI wireless infrastructure solution. The hybrid WMN model employs a network architecture that uses the wireless mesh technologies, and the pointto-multipoint technologies to network many thousands of wireless nodes together for the network communication. The hybrid WMN model uses the WiMAX (IEEE 802.16d) and Wi-Fi (IEEE 802.11 a/b) technologies [INTL04, HWC08]. We are interested in the hybrid architecture because it is high performance and scalable. These properties are very important because AMI meter data reporting application will be deployed in the large areas. 3.2.2 Simulate the AMI Meter Data Reporting process Many network simulation experiments will be created. The WMN simulation process is divided into the smaller network topologies simulation processes. We can create and simulate the simulation experiments for Wireless LAN, Wireless NAN, Wireless MAN, and WAN topologies. We also develop a network traffic generator application that simulates the real time meter data reporting process from the smart meters to the data center. The network simulation process can be implemented on the simulation software NS-3 [NS3]. 21 3.2.3 Analyze the Simulation Results The network throughput (the number of messages received in one second) will be derived from the simulation results to see whether the communication network can transport the meter data from all of the meters to the data center in one second. The WMN model is also investigated about the trade-off between the scalability and the performance, and that can help the optimization in the network designing phase. 3.3 Summary For the WMN infrastructure solution, there are some issues concerning about the AMI meter data collection application. We will briefly discus the issues and the solutions. Firstly, the application deployment is throughout a large geographical area, such as a city or a metropolitan. So, there is the need for the installation of the large wireless networks or so called wireless metropolitan area network (WMAN). This issue can be accomplished by carefully planning the network topology and capacity. In this thesis, we will introduce the wireless networking solutions using the modern wireless network technologies such as WiMAX and Wi-Fi. We also discuss the planning and designing of the WMAN infrastructure using these wireless networking technologies. We will develop the tools and techniques to assist the planning and designing process. Secondly, how we can evaluate the performance of such larger wireless network infrastructure. In the scope of this thesis, for evaluating network performance measurement, we will use the network simulation method to accomplish this issue. 22 We will develop a network model for our wireless mesh network infrastructure solution. Then we will simulate the network model using the network simulation software NS-3. The simulation results will be analyzed for the evaluation of the network performance. Chapter 4 Planning, and Implementing the Simulation 4.1 Introduction to the Smart Grid Wireless Infrastructure Planning (SG-WIP) Tool The SG-WIP is a Wireless Network Topology Planning Application. We have developed this planning tool to assist the planning, and designing phase of the AMI wireless network infrastructure. Figure 4.1 shows the GUI of SG-WIP. The SG-WIP is a Google Maps mashup [Goog01, PSC06]. It can provide the information about the geographical location of the network topologies, network devices, or the residential housing units in the service areas of the utility. 24 Figure 4.10 - SG-WIP tool for planning AMI wireless infrastructure network in Colorado Springs In the network planning phase, we have conducted some researches that use the SGWIP tool. The research for antenna placement of the WiMAX/Wi-Fi networks has employed the SG-WIP platform as a tool to extract information of the geographical network topologies such as housing unit locations, or street light poles. Figure 4.2 shows the planning antennae placement for the smart meters and the WiMAX/Wi-Fi gateway on the Google Maps. 25 Figure 4.11 - Using SG-WIP tool for planning the antennae position. The WiMAX/Wi-Fi gateway was place on streetlight pole. The research about housing unit density of the designing wireless networks has also used the SGWIP platform to gather the distribution of the housing units. Table 4.1 shows the range of number housing units in the LAN, NAN, WAN topologies. The dimensioning information is helpful for the designing of smart grid network simulation. For example, Table 4.1 shows the number of housing units in the LAN, NAN, MAN topologies for the conducted simulation. Low Bound (housing units) LAN NAN MAN High Bound (housing units) Simulation 0 51 50 0 1,054 950 0 40,501 27,000 Table 4.12 - The ranges of housing unit density of the LAN, NAN, MAN topologies in Colorado Springs. 26 Figure 4.3 shows the WLAN topology size 100x100 square meters that has fifty housing units. Figure 4.12 - The WLAN topology (100x100 square meters) has a high density of resident housing units. The exported information about the network topologies from SG-WIP platform, as well as the research results about the housing unit density, and the antenna locations can help the AMI network infrastructure researchers and designers in the simulation and analysis of the wireless network infrastructure of the AMI. 27 4.2 Planning the Network Simulation The following network topologies will be simulated: o Wireless Local Area Network (WLAN) o Wireless Neighborhood Area Network (WNAN) o Wireless Metropolitan Area Network (WMAN) o Wide Area Network (WAN) The main purpose is for evaluating the network throughput of the Hybrid WiMAX/Wi-Fi Infrastructure that will be employed for the AMI meter reading reporting application o o Network topologies WiMAX, Wi-Fi technologies Grid Topology: with pre-defined distance between wireless nodes Adequate bandwidth data link connection Applications Traffic pattern: Up-link data flows from the Smart Meter nodes to the Utilities Data Center node Each Smart Meter sends one meter reading message to the Data Center in every second. The network throughput is calculated based on the number of arrived messages in every one second at the Data center. o The network throughput is measured from many simulation experiments that have the inputs as following: Number of Smart Meter nodes 28 Number of Wireless Mesh Hops, and Access Points Number of WiMAX/Wi-Fi Gateways Number of WiMAX Base Stations The transmission delay (Tx Delay) of a meter data message is designed to measure the average delay of the transmission of a meter data message throughout the network infrastructure. 4.3 Design the Network Simulation 4.3.1Physical Network Model 4.3.1.1 The Hybrid WMN Architecture There are three types of WMNs: Flat WMN, Hierarchical WMN, and Hybrid WMN [HWC08]. The brief description for these WMN categories is as following: 4.3.1.1.1 Flat Wireless Mesh Network The flat WMN includes nodes that have roles as both client and router. The nodes can perform the networking functionalities such as routing, network configuration, services, and other applications. This architecture is similar to the Ad-hoc wireless network and it is the simplest type among the three WMN architecture types. Its disadvantages are lack of network scalability and high resource constraints. 4.3.1.1.2 Hierarchical Wireless Mesh Network The hierarchical WMN has multiple tiers or levels. The client nodes form the lowest tier in the hierarchy. The client nodes communicate together through the backbone network formed by WMN routers. The WMN routers are the dedicated nodes for routing 29 functions. They are not source or destination of data traffic like the client nodes. In the backbone network, there are some router nodes that may have external connections to the other resources such as the Internet, and other servers in wired networks, and then such nodes are called gateway nodes. 4.3.1.1.3 Hybrid Wireless Mesh Network Hybrid WMN is a special case of the hierarchical WMN where the WMN utilizes other wireless networks for communication. For example, the hierarchical WMN that has the client and router nodes used the Wi-Fi technology, can employ the infrastructure-based networks such as cellular, WiMAX, or satellite networks to connect to the Internet. The hybrid WMNs can utilize multiple technologies for both WMN backbone and backhaul. Since the growth of the WMNs depend heavily on the ability to work with other existing wireless networking solutions, this architecture type is very important in the future. In the figure 4.4, the WiMAX has been use directly as part of Wi-Fi mesh network. The WiMAX Subscriber Terminal put on the Wi-Fi Mesh Access Point. So the Wi-Fi Networks automatically are more reliable in wider coverage area, and reduce cost of connections that are caused by cable drawing in the gateway installation. 30 Figure 4.13 - WiMAX as backhaul inters Wi-Fi mesh networks (source: Intel) 4.3.1.2 The WiMAX/Wi-Fi Network Infrastructure Basically, the WM Communication Network component provides the data transportation services. The requests and responses from Meter Data Center component and Wi-Fi Smart Meter component will be delivered by the using to the transportation services of WM Communication Network component. The WM Communication Network component has three layers of network services like the first three layers of the OSI model [OSI]: 31 Figure 4.14 - Logical view of the WM Communication Network includes the first three layers of the OSI model The WM Communication Network is an integrated Wireless Mesh Network (WMN), which uses Wi-Fi and WiMAX technologies [INTL04]. The WM Communication Network has the WiMAX Base Station, the WiMAX/Wi-Fi Gateway, and Wi-Fi Dual Band Mesh Routers. The figure 4.6 shows the physical model of the wireless mesh communication network. The WiMAX Base Stations are connected to the Meter Data Center through wired network. The Wi-Fi mesh routers are at the bottom level of the network hierarchy and can connect with the Wi-Fi smart meters. Wi-Fi smart meters connect to the meter data center via the hybrid WiMAX/Wi-Fi Communication Network. 32 Figure 4.15 - Physical model of the WM Communication Network. The network hierarchy includes the Wi-Fi Mesh Routers, the WiMAX/Wi-Fi Gateways, and the WiMAX BS. 33 4.3.1.3 An Overview of the NS-3 WiMAX Module The NS-3 WiMAX model attempts to provide an accurate MAC and PHY level implementation of the IEEE 802.16 specification with the Point-to-multipoint (PMP) mode and the Wireless MAN-OFDM PHY layer. The WiMAX model composed of three layers: The MAC Convergence Sub layer (MAC-CS) The MAC Common Part Sub layer (MAC-CPS) The Physical (PHY) layer The MAC Convergence Sub layer (CS) The MAC-CS in this module implements the Packet CS, designed to work with the packet-based protocols at higher layers. The CS is responsible of receiving packet from the higher layer and from peer stations, classifying packets to appropriate connections (or service flows) and processing packets. It keeps a mapping of transport connections to service flows. This enables the MAC CPS identifying the Quality of Service (QoS) parameters associated to a transport connection and ensuring the QoS requirements. The MAC Common Part Sub layer (MAC-CPS) The MAC Common Part Sub layer (CPS) is the main sub layer of the IEEE 802.16 MAC and performs the fundamental functions of the MAC. The module implements the PointMulti-Point (PMP) mode. In PMP mode BS is responsible of managing communication among multiple SSs. The key functionalities of the MAC-CPS include framing and addressing, generation of MAC management messages, SS initialization and registration, service flow management, bandwidth management and scheduling services. 34 Framing and Management Messages The module implements a frame as a fixed duration of time, i.e., frame boundaries are defined with respect to time. Each frame is further subdivided into downlink (DL) and uplink (UL) sub frames. The module implements the Time Division Duplex (TDD) mode where DL and UL operate on same frequency but are separated in time. A number of DL and UL bursts are then allocated in DL and UL sub frames, respectively. Since the standard allows sending and receiving bursts of packets in a given DL or UL burst, the unit of transmission at the MAC layer is a packet burst. The module implements a special Packet Burst data structure for this purpose. A packet burst is essentially a list of packets. In the case of DL, the sub frame is simulated by transmitting consecutive bursts (instances Packet Burst). In case of UL, the sub frame is divided, with respect to time, into a number of slots. The bursts transmitted by the SSs in these slots are then aligned to slot boundaries. The frame is divided into integer number of symbols and Physical Slots (PS) which helps in managing bandwidth more effectively. The number of symbols per frame depends on the underlying implementation of the PHY layer. The size of a DL or UL burst is specified in units of symbols. Network Entry and Initialization The network entry and initialization phase is basically divided into two sub-phases, (1) Scanning and synchronization and (2) Initial ranging. The entire phase is performed by the LinkManager component of SS and BS. Connections and Addressing All communication at the MAC layer is carried in terms of connections. The standard defines a connection as a unidirectional mapping between the SS and BS's MAC entities 35 for the transmission of traffic. The standard defines two types of connections: the Management Connections for transmitting control messages and the Transport Connections for data transmission. Note that each connection maintains its own transmission queue where packets to transmit on that connection are queued. The ConnectionManager component of BS is responsible of creating and managing connections for all SSs. Scheduling Services The module supports the four scheduling services defined by the IEEE 802.16-2004 standard: Unsolicited Grant Service (UGS) Real-Time Polling Services (rtPS) Non Real-Time Polling Services (nrtPS) Best Effort (BE) These scheduling services behave differently with respect to how they request bandwidth as well as how it is granted. Each service flow is associated to exactly one scheduling service, and the QoS parameter set associated to a service flow actually defines the scheduling service it belongs to. When a service flow is created the UplinkScheduler calculates necessary parameters such as grant size and grant interval based on QoS parameters associated to it. WiMAX PHY Model The Wireless MAN OFDM PHY specification is implemented. This specification is designed for non-light-of-sight (NLOS) including fixed and mobile broadband wireless access. The proposed model uses a 256 FFT processor, with 192 data subcarriers. It 36 supports all the seven modulation and coding schemes specified by Wireless MANOFDM. It is composed of two parts: the channel model and the physical model. Channel model When a physical device sends a packet (FEC Block) to the channel, the channel handles the packet, and then for each physical device connected to it, it calculates the propagation delay, the path loss according to a given propagation model and eventually forwards the packet to the receiver device. Physical model The physical layer performs two main operations: (i) It receives a burst from a channel and forwards it to the MAC layer, (ii) it receives a burst from the MAC layer and transmits it on the channel. Transmission Process: A burst is a set of WiMAX MAC PDUs. At the sending process, a burst is converted into bit-streams and then split into smaller FEC blocks which are then sent to the channel with a power equal P_tx. Reception Process: The reception process includes the following operations: 1- Receive a FEC block from the channel. 2- Calculate the noise level. 3- Estimate the signal to noise ratio (SNR) with the following formula. 4- Determine if a FEC block can be correctly decoded. 5- Concatenate received FEC blocks to reconstruct the original burst. 6- Forward the burst to the upper layer. The below figure 4.3 shows an overview of the WiMAX sub-layers traversed for transmitting and receiving a packet. More detailed information about the NS-3 WiMAX model is presented in [NS3]. 37 Figure 4.16 - NS-3 WiMAX protocol stack overview 4.3.1.4 An Overview of the NS-3 Wi-Fi Module The NS-3 802.11 model provides an accurate MAC-level implementation of the 802.11 specification and the PHY-level model of the 802.11a and 802.11b specifications. There are four levels that were implemented in the current implementation: The PHY layer model The so-called MAC low models The so-called MAC high models A set of Rate control algorithms used by the MAC low models 38 The PHY layer implements a single 802.11a model in the ns3::WifiPhy class, and recently extended to cover 802.11b physical layers. The MAC low layer is split in 3 components: ns3::MacLow takes care of RTS/CTS/DATA/ACK transactions ns3::DcfManager and ns3::DcfState implement the DCF functions ns3::DcaTxop and ns3::EdcaTxopN handle the packet queue, packet fragmentation, and packet retransmissions. The MAC high models contain the implementations for three Wi-Fi topological elements – Access Point (AP) implemented in ns3::ApWifiMac, non-AP Station (STA) implemented in ns3::StaWifiMac, and STA in an Independent Basic Service Set (IBSS) implemented in ns3::AdhocWifiMac. Rate control Algorithms include: ns3::ArfWifiManager ns3::AarfWifiManager ns3::IdealWifiManager ns3::CrWifiManager ns3::OnoeWifiManager ns3::AmrrWifiManager ns3::CaraWifiManager ns3::AarfcdWifiManager The below figure 4.4 shows the overview of the Wi-Fi L2 sub-layers traversed for transmitting and receiving a packet. More detailed information about the NS-3 Wi-Fi model is presented in [NS3]. 39 Figure 4.17 - NS-3 Wi-Fi layer 2 stack overview 4.3.2 The Application Model 4.3.2.1 The Client-Server Architecture The AMI metering data collection process includes three components that are Meter Data Center, Wireless Mesh (WM) Communication Network, and Wi-Fi (WF) Smart Meter. The Meter Data Center component accesses the WF Smart Meter’s reading via the WM Communication Network as in the Figure 4.9. 40 Figure 4.18 - Smart meters access the Meter data center through the Wireless mesh communication network 4.3.2.2 The Generation of Meter Data Traffic Our current software simulates constant bit rate traffic. We allow users specifying the starting time of packet streams. This allows for better network performance since the packets from different nodes will not collide. It also helps debug the end to end transmission and ensures that the network properly delivers the packets. 4.3.2.3 The NS-3 Server Application An UDP protocol Server. It receives the meter messages. 4.3.2.4 The NS-3 Client Application An UDP protocol Client. It sends the meter messages to the Server. 4.3.3 The WLAN Simulation Design 4.3.3.1 Topology Configuration Standard: Wi-Fi IEEE 802.11b Connection mode: Infrastructure Smart Meter (SM) at random position within the coverage area of the corresponding AP 41 The Wi-Fi AP has the coverage range of 100 meters Number of SMs: [1 – 100] Wi-Fi link capacity: 11Mbps 4.3.3.2 Application Configuration Server application is installed on the AP. Client application is installed on SM. Each Client application will send one meter message with 20 bytes length to the Server application by using the Internet protocol UDP. The Client application’s Data-Rate property is set to 20 bytes x 8 bits = 160bps = 0.160kbps 4.3.3.3 Simulation Planning Repeatedly running the simulation scenarios with the different number of SMs Output: the network throughput, Tx Delay 4.3.3.4 Results Analysis and Conclusion Calculate the average network throughput, Tx delay Conclusion: Do the AP receive all of the messages from the SMs in 1 second? 4.3.4 The WNAN Simulation Design 4.3.4.1 Topology Configuration Standard: Wi-Fi IEEE 802.11a Connection mode: Mesh 42 The Mesh Routers (MR) /Access Points (AP) are installed in the Grid topology o Distance between adjacent nodes (horizontal and vertical): 200 meters Number of MRs/APs: [1 – 9] Wi-Fi link capacity: 54Mbps 4.3.4.2 Application Configuration Server application is installed on the Gateway (GW). Client application is installed on APs. Each Client application will send 100 messages, which have 20 bytes length, to the Server application by using the Internet protocol UDP. The Client application’s Data-Rate property is set to 100 x 20 bytes x 8 bits = 16000bps = 16kbps 4.3.4.3 Simulation Planning Repeatedly running the simulation scenarios with the different number of MRs and APs Output: the network throughput, Tx delay 4.3.4.4 Results Analysis and Conclusion Calculate the average network throughput, Tx delay Conclusion: Do the GW receive all of the messages from the APs in 1 second? 43 4.3.5 The WMAN Simulation Design 4.3.5.1 Topology Configuration Standard: WiMAX IEEE 802.16d Connection mode: Point-To-Multipoint The Subscribers (SS)/Gateways (GW) are installed in the grid topology. Distance between adjacent nodes (horizontal and vertical): 1,000 meters Number of SSs/GWs: [1 -10] WiMAX link capacity: 4Mbps 4.3.5.2 Application Configuration Server application is installed on the Base Station (BS). Client application is installed on SSs. Client application will send 900 messages, which have 20 bytes length, to the Server application by using the Internet protocol UDP. The Client application’s Data-Rate property is set to 900 x 20 bytes x 8 bits = 144,000bps = 144kbps 4.3.5.3 Simulation Planning Repeatedly running the simulation scenarios with the different number of SSs/GWs Output: the network throughput, Tx delay 4.3.5.4 Results Analysis and Conclusion Calculate the average network throughput, Tx delay 44 Conclusion: Do the BS receive all of the messages from the SSs/GWs in 1 second? 4.3.6 The WAN Simulation 4.3.6.1 Topology Configuration Standard: Ethernet EEE 802.3 Connection mode: Point-To-Point The BSs are connected to the Hub (or Data Center) in the Star topology Number of BS: [1-20] Ethernet link capacity: 10Mbps 4.3.6.2 Application Configuration Server application is installed on the Hub (or DC) Client application is installed on BSs. Client application will send 9,000 messages, which have 20 bytes length, to the Server application by using the Internet protocol UDP. The Client application’s Data-Rate property is set to 9,000 x 20 bytes x 8 bits = 1,440,000bps = 1.44Mbps 4.3.6.3 Simulation Planning Repeatedly running the simulation scenarios with the different number of BSs Output: the network throughput, Tx delay 4.3.6.4 Results Analysis and Conclusion Calculate the average network throughput, Tx delay 45 Conclusion: Do the DC receive all of the messages from the BSs in 1 second? 4.4 Implementing the Network Simulation 4.4.1The WLAN Simulation 4.4.1.1 The NS-3 Script Name: sm-ap-sim.cc Description: This script implements the network model that simulates the AMI meter data reporting process in a WLAN topology. The simulation scenarios have one Wi-Fi Access Point (AP) and a number of the smart meters (SM). The network devices are layout in a grid topology. The AMI meter data reporting application will send the meter messages from the SMs to the AP. The source code of this script is in the Appendix session. Syntax: o Input: nbSM - number of smart meter nodes to create [1] duration - duration of the simulation in seconds [10] verbose - turn on all WimaxNetDevice log components [false] data-rate - packet data rate [0.160kbps] statistic-start - the statistic is started at (second) [0] o Output: 46 In every second: Transmit (Tx) Packets, Receive (Rx) Packets, and Maximum Tx Delay In simulation period: Average Transmit (Tx), Receive (Rx), and Transmit Delay (TxDelay) 4.4.1.2 The Linux Shell Script Name: sm-ap-sim.sh Description: Batch running the WLAN simulation application. This shell script generates many WLAN simulation scenarios. Then it simulates the scenarios, and logs the simulation results in the text files. Syntax: Input: none Output: List of the log file names that store the simulation results 4.4.2 The WNAN Simulation 4.4.2.1 NS-3 Script Name: ap-gw-sim.cc Description: This script implements the network model that simulates the AMI meter data reporting process in a WNAN topology. The simulation scenarios have one WiMAX/Wi-Fi gateway and a number of the mesh routers. The network devices are layout in a grid topology. Some of the 47 mesh routers are configured as the APs. The AMI meter data reporting application will send the meter messages from the APs to the gateway. The source code of this script is in the Appendix session. Syntax: o Input: x-size - number of columns of the grid [3] y-size - Number of rows of the grid [3] step - distance between two adjacent nodes (meter) [190] access-points - number of Wi-Fi APs [1] data-rate - packet data rate [20kbps] statistic-start - the statistic is started at (second) [0] o Output: In every second: Transmit (Tx) Packets, Receive (Rx) Packets, and Maximum Tx Delay In simulation period: Average Transmit (Tx), Receive (Rx), and Transmit Delay (TxDelay) 4.4.2.2 Linux Shell Script Name: ap-gw-sim.sh Description: Batch running the WNAN simulation application. This shell script generates many WNAN simulation scenarios. Then it simulates the scenarios, and logs the simulation results in the text files. 48 Syntax: o Input: none o Output: List of the log file names that store the simulation results 4.4.3The WMAN Simulation 4.4.3.1 NS-3 Script Name: gw-bs-sim.cc Description: This script implements the network model that simulates the AMI meter data reporting process in a WMAN topology. The simulation scenarios have one WiMAX Base Station and a number of the Subscriber Stations (or WiMAX/Wi-Fi Gateways). The network devices are layout in a grid topology. The AMI meter data reporting application will send the meter messages from the Subscriber Stations to the Base Station. The source code of this script is in the Appendix session. Syntax: o Input: nbSS - number of subscriber station to create [1] scheduler - type of scheduler to use with the network devices [0] duration - duration of the simulation (second) [10] verbose - turn on all WimaxNetDevice log components [false] data-rate - packet data rate [144kbps] statistic-start - statistic started at (second) [0] o Output: 49 In every second: Transmit (Tx) Packets, Receive (Rx) Packets, and Maximum Tx Delay In simulation period: Average Transmit (Tx), Receive (Rx), and Transmit Delay (TxDelay) 4.4.3.2 Linux Shell Script Name: gw-bs-sim.sh Description: Batch running the WMAN simulation application. This shell script generates many WMAN simulation scenarios. Then it simulates the scenarios, and logs the simulation results in the text files. Syntax: o Input: none o Output: List of the log file names that store the simulation results 4.4.4The WAN Simulation 4.4.4.1 NS-3 Script Name: bs-dc-sim.cc Description: This script implements the network model that simulates the AMI meter data reporting process in a MAN topology. The simulation scenarios have one Hub and a number of the WiMAX Base Stations. The network devices are layout in a star topology. The AMI meter data reporting application will send the meter messages from the Base Stations to the Hub node (or the Data Center). The source code of this script is in the Appendix session. 50 Syntax: o Input: nbBS - number of base station to create [1] duration - duration of the simulation (second) [10] verbose - turn on all WimaxNetDevice log components [false] data-rate - packet data rate [1.44Mbps] statistic-start - statistic started at (second) [0] o Output: In every second: Transmit (Tx) Packets, Receive (Rx) Packets, and Maximum Tx Delay In simulation period: Average Transmit (Tx), Receive (Rx), and Transmit Delay (TxDelay) 4.4.4.2 Linux Shell Script Name: bs-dc-sim.sh Description: Batch running the WAN simulation application. This shell script generates many WAN simulation scenarios. Then it simulates the scenarios, and logs the simulation results in the text files. Syntax: o Input: none o Output: List of the log file names that store the simulation results Chapter 5 Simulation Results and Analysis 5.1 The Simulation Experiments We has conducted four types of the network simulation experiments based on the type of network topologies, including WLAN, WNAN, WMAN, and WAN topologies. We have run each simulation experiment at least five times to compare the simulation results. After the results were validated, the results from the last simulation were used to prepare the input for a new simulation cycle of the parent network in the hierarchy. For example, the WLAN simulation shows that there are 100 UDP packets transmitted in one second from the SMs to the AP. Then, in the parent network, WNAN, the APs will be configured to send the same number of packets received from the WLAN simulation, or 100 packets in this example. 5.1.1 The WLAN Simulation Experiment 52 The goal of the experiments is to evaluate the network throughput and the UDP packet transmission delay with the different number of SMs in the WLAN topologies. There are 11 experiments conducted to simulate the meter data traffic from the SMs to the AP. The number of SMs is different between the scenarios, and between 1 and 100. The location of the AP is fixed, but the location of the SMs was generated randomly in each scenario. Based on the analysis of the Colorado Springs Utility network described in Chapter 4, we observed there are average 50 SMs within 100x100 meter square area. That is the reason we choose 50 as the number of SMs in a WLAN topology for the simulation. The simulations results are shown and discussed in Section 5.3.1. 5.1.2 The WNAN Simulation Experiment The goal of the experiment is to evaluate the network throughput and the UDP packet transmission delay with the different number of MRs and APs in the WNAN topologies. There are 9 experiments conducted to simulate the meter data traffic from the APs to the GW. The number of APs is different between the experiments, and from 1 to 9. The network devices, GW and MRs/APs were installed in a grid topology with the distance between nodes is 200 meters. GW position is at the left-top node. MRs/APs are installed at other nodes of grid. The number of hops in a mesh routing path will increase with the increasing number of the MSs/APs. The NS-3 mesh simulation module which we used in this study limits the number of APs to nine. The simulations results are shown and discussed in Section 5.3.2. 5.1.3 The WMAN Simulation Experiment 53 The goal of the experiment is to evaluate the network throughput and the UDP packet transmission delay with the different number of GWs in the WMAN topologies. There are 10 experiments conducted to simulate the meter data traffic from the GWs to the BS. The number of GWs is different between the experiments, and from 1 to 10. The network devices, BS and GWs were installed in a grid topology with the distance between nodes is 1,000 meters. BS position is at the left-top node. GWs are installed at other nodes of grid. The NS3 WiMAX simulation module which we used in this study limits the number of GWs to 20 but we have observed if the number of GWs increases beyond ten, the packets will be lost. Improve Meter Data Transmission Through Packet Aggregation To improve the meter data transmission in the WMAN, we observed that the WiMAX frame duration length is about 5 milliseconds that causes the maximum number of frames processed in one second at a WiMAX/Wi-Fi gateway is about 200. It is not a good utilization because there is only one meter data packet put in the sending UDP packet during 5 ms of frame processing time. Instead, we can send more than one meter data packets in one sending UDP packet by aggregating the received meter data packets at the gateway into a single UDP packet and transmitting it with a WiMAX frame. For example, in 5ms duration, the WiMAX connection with a transmission speed of 1Mbps can deliver 5,000 bits or 625 bytes. If the length of the meter UDP packet is 20 bytes, then the number of meter packets can be transmitted in one second is 31. To evaluate the proposed improvement, we conduct simulation experiments , where 10 gateways connected to the base station in WiMAX point-to-multipoint mode. The network performance is measured against the number of meter data packets put in a 54 WiMAX frame. The simulation parameter “number of meter data packets” increased until the network is overloaded, or the number of received packets less than the number of sent packets. The simulation results are shown and discussed in Section 5.3.3. 5.1.4 The WAN Simulation Experiment The goal of the experiments is to evaluate the network throughput and the UDP packet transmission delay with the different number of BSs in the WAN topologies. There are 7 experiments conducted to simulate the meter data traffic from the BSs to the DC. The number of BSs is different between the experiments, and between 1 and 7. The network devices, DC and BSs, were installed in a star topology. The connection between DC and BS is Point-to-Point that simulates that optical fiber connection. To evaluate the affect of the cable length to the transmission delay of a UDP packet, we conduct 11 experiments that have the cable length changed from 1km to 100km. The simulations results are shown and discussed in Section 5.3.4. 5.2 Simulation Data Collection Because the network infrastructure simulation process was divided into four subnetworks such as WLAN, WNAN, WMAN, and WAN simulations. We can orderly simulate and analyze each type of network topology. Therefore, we collected the simulation results in each sub-network simulation. The simulation results were displayed on the standard output device by the NS-3 C++ scripts. Four Linux shell scripts were developed to run the simulation experiments many times for result validation. We have modified the original standard output into the text file for offline further analysis. 55 5.3 The Simulation Results The following tables show the simulation results. The specification of the simulation design, and the NS-3 simulation implementation are included in Chapter 4. 5.3.1 The WLAN Simulation Results 5.3.1.1 Experiment 1: WLAN topology with 50 SMs Topology configuration Standard: Wi-Fi IEEE 802.11a Connection mode: Infrastructure The number of smart meters which the Wi-Fi AP serves: 50 Wi-Fi link capacity: 24Mbps Smart meter location: random position within the coverage area of the AP NS3 Simulation Time in Sec 1 2 3 4 5 6 7 8 9 10 11 12 13 14 # of Packets 0 0 50 50 50 50 50 50 50 50 50 50 50 50 Tx # of Rx Packets 0 0 50 50 50 50 50 50 50 50 50 50 50 50 Avg Tx Delay (µs) 0 0 36,011 9,800 10,025 10,211 9,418 9,581 9,164 10,685 9,587 10,023 9,993 9,835 # of Tx Packets / Total Processing Meter Delay (µs) 1 0 1 0 1 36,011 1 9,800 1 10,025 1 10,211 1 9,418 1 9,581 1 9,164 1 10,685 1 9,587 1 10,023 1 9,993 1 9,835 56 15 16 17 18 19 20 50 50 50 50 50 50 50 50 50 50 50 50 10,038 10,735 9,701 9,940 9,805 11,209 1 1 1 1 1 1 10,038 10,735 9,701 9,940 9,805 11,209 Table 5.13 – The WLAN simulation results with 50 SMs. The statistical data are in one second period The first two second periods of the simulation were in the initialization phase of the WiFi network infrastructure mode. In the initialization period, there were no data sent in the first two seconds. Moreover, the third second period shows that the average delay to be 36,011 µseconds. This is due to the Wi-Fi nodes need to resolve the AP’s IP address before they send the UDP meter data packets to it. Otherwise, the average delay is converged to about 10,000 µseconds. 5.3.1.2 Summary of the WLAN Simulation Experiments Avg. Tx # of # of Tx # of Rx Delay Meters Packets Packets (µs) 1 1 1 156 10 10 10 1,420 20 20 20 3,127 30 30 30 5,326 40 40 40 7,479 50 50 50 9,985 60 60 60 12,367 70 70 70 14,559 80 80 80 16,866 90 90 90 19,371 100 100 100 21,132 # of Tx Total Packets / Processing meter Delay (µs) 1 156 1 1,420 1 3,127 1 5,326 1 7,479 1 9,985 1 12,367 1 14,559 1 16,866 1 19,371 1 21,132 Table 5.14 - The results of WLAN simulations with different number of SMs. The statistical data in each row are the results of one simulation experiment. 5.3.2 The WNAN Simulation Results 57 5.3.2.1 Experiment 1: The WNAN topology with 9 APs Topology Configuration Standard: Wi-Fi IEEE 802.11s Connection mode: Mesh Wi-Fi link capacity: 54Mbps The Mesh Routers (MR) /Access Points (AP) are installed in a grid topology NS-3 Simulation Time in Sec 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Distance between adjacent nodes (horizontal and vertical): 200 meters # of Tx Packets 441 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 # of Rx Packets 374 405 400 412 450 265 374 303 456 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 Avg Tx (µs) 5,037 8,031 730 3,718 685 4,959 234,084 189 5,507 224 213 227 203 198 206 208 213 198 264 219 199 191 190 251 Delay # of Tx Packets / APs 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 Total Processing Delay (µs) 251,839 401,555 36,518 185,894 34,239 247,975 11,704,216 9,442 275,363 11,207 10,636 11,366 10,171 9,899 10,295 10,391 10,665 9,886 13,223 10,960 9,959 9,538 9,490 12,550 58 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 293 290 266 239 246 214 152 158 130 130 277 245 240 236 236 5,472 146 148 146 146 2,828 192 192 200 191 268 176 180 179 176 243 206 190 189 192 205 2,937 227 231 233 231 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 14,637 14,475 13,308 11,950 12,281 10,677 7,591 7,901 6,478 6,524 13,851 12,229 12,010 11,809 11,786 273,620 7,289 7,396 7,287 7,308 141,386 9,621 9,608 9,980 9,539 13,390 8,824 9,001 8,933 8,789 12,125 10,297 9,493 9,440 9,610 10,266 146,842 11,348 11,553 11,640 11,533 59 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 450 449 450 450 450 450 450 450 450 450 5,518 246 237 233 236 269 170 175 164 171 1,340 159 161 161 165 250 214 221 215 223 2,877 254 244 247 254 2,881 156 151 149 148 173 1,206 128 130 130 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 275,912 12,305 11,835 11,631 11,784 13,467 8,485 8,731 8,190 8,526 66,994 7,960 8,066 8,049 8,243 12,522 10,692 11,050 10,742 11,151 143,872 12,717 12,186 12,354 12,718 144,026 7,808 7,559 7,440 7,378 8,667 60,298 6,397 6,499 6,479 Table 5.15 – The simulation results for WNAN 3x3 grid topology with nine APs. The statistical data are in one second period The initialization phase of the Wi-Fi Mesh network in the simulation occurred in the first nine seconds. The mesh routing protocol needs to construct the routing path between the 60 APs and the gateway before UDP packets can be delivered to the receiver or mesh gateway. This explains why there were the lost packets in the network initialization period. Other observation is the big jump on the delay of packet transmission at some simulation seconds, i.e. 40, 45, 66. That is due to the changing in the routing path of the mesh network. The new routing paths have more hops than the former ones. As a result, the delay time has rapidly increased with the hop number on the routing path [HWC08]. In the first second period, the number of sent UDP packets was less than 450. That is due to the schedule for starting of traffic applications. The start time of traffic applications on the APs were extendedly shifted for the performance measurement. The traffic applications that have the starting time shifted far away from the starting of the first simulation second, could not send all 50 UDP packets in the first second as planning. As a result, the total sent packets in the first second were less than 450. The delay time was converged to 500 µseconds. 5.3.2.2 Summary of the WNAN Simulation Experiments # of APs 1 2 3 4 5 6 7 8 9 # of Packets 50 100 150 200 250 300 350 400 450 Tx # of Packets 50 100 150 200 250 300 350 400 450 Total Rx Avg. Tx Delay # of Tx Packets / Processing (µs) APs Delay (µs) 0 50 0 21 50 1,036 29 50 1,432 34 50 1,696 64 50 3,203 103 50 5,162 113 50 5,649 158 50 7,879 496 50 24,800 Table 5.16 – The results of WNAN simulation. The statistical data in each row are the results of one simulation experiment. 61 5.3.3 The WMAN Simulation Results 5.3.3.1 Experiment 1: The WMAN topology with 10 GWs Topology Configuration Standard: WiMAX IEEE 802.16d Connection mode: Point-To-Multipoint WiMAX link capacity: 4Mbps The Subscribers (SS)/Gateways (GW) are installed in the grid topology Distance between adjacent nodes (horizontal and vertical): 1,000 meters NS-3 Simulation Time in Sec 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 # of Tx Packets 0 0 0 0 0 0 1791 1800 1800 1800 1800 1800 1800 1800 1800 1800 1800 1800 1800 # of Rx Packets 0 0 0 0 0 0 1782 1803 1803 1800 1802 1799 1797 1793 1802 1799 1804 1801 1802 Avg Tx (µs) 0 0 0 0 0 0 5,315 5,266 5,312 5,372 5,348 5,297 5,305 5,315 5,315 5,295 5,290 5,368 5,277 Delay # of Tx Packets / GW 180 180 180 180 180 180 180 180 180 180 180 180 180 180 180 180 180 180 180 Total Processing Delay (µs) 0 0 0 0 0 0 956,704 947,964 956,076 966,898 962,597 953,517 954,901 956,689 956,619 953,111 952,218 966,236 949,810 62 20 21 22 23 24 25 26 27 28 29 30 1800 1800 1800 1800 1800 1800 1800 1800 1800 1800 1800 1803 1798 1801 1798 1797 1796 1800 1802 1805 1800 1803 5,312 5,394 5,314 5,297 5,369 5,311 5,333 5,382 5,228 5,237 5,383 180 180 180 180 180 180 180 180 180 180 180 956,091 970,940 956,604 953,541 966,495 955,962 959,900 968,784 941,108 942,595 968,973 Table 5.17 – The simulation results for WMAN Point-to-multipoint topology with ten GWs. The statistical data are in one second period. There were no packets sent in the first six seconds as planning because of WiMAX network initialization period. The number of sent packets in the seventh second was less than 1,800 as planning because of the shifted starting time of traffic applications. The IEEE 802.16d standard has the frame time of 5 milliseconds [IPGT10]. As a result, the maximum number of WiMAX frames that can be sent in one second, is 180. The average delay time of a UDP packet is close to the standard frame time. 5.3.3.2 Summary of the WMAN Simulation Experiments # of GWs 1 2 3 4 5 6 7 8 9 10 # of Tx Packets 180 360 540 720 900 1080 1260 1440 1620 1800 # of Rx Packets 180 360 540 720 900 1080 1260 1440 1620 1800 Avg. Tx Delay (µs) 5,147 5,158 5,171 5,166 5,161 5,159 5,166 5,158 5,229 5,321 Total # of Tx Packets / Processing GW Delay (µs) 180 926,509 180 928,504 180 930,743 180 929,896 180 928,934 180 928,643 180 929,883 180 928,513 180 941,181 180 957,790 Table 5.18 – The WMAN simulation results. The statistical data in each row are the results of a simulation experiment. 63 5.3.3.3 Summary of the Experiments for WMAN Improved Design # of Meter Data Packets / Tx Packet 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 Total of Tx Meter # of Tx # of Rx Data Packets Packets Packets 1,800 1,800 1,800 1,800 1,800 3,600 1,800 1,800 5,400 1,800 1,800 7,200 1,800 1,800 9,000 1,800 1,800 10,800 1,800 1,800 12,600 1,800 1,800 14,400 1,800 1,800 16,200 1,800 1,800 18,000 1,800 1,800 19,800 1,800 1,800 21,600 1,800 1,800 23,400 1,800 1,800 25,200 1,800 1,800 27,000 1,800 1,786 28,800 1,800 1,786 30,600 Total of Rx Meter Data Packets 1,800 3,600 5,400 7,200 9,000 10,800 12,600 14,400 16,200 18,000 19,800 21,600 23,400 25,200 27,000 28,576 30,362 Tx Delay (µs) 5,319 5,320 5,320 5,348 5,348 5,349 5,374 5,375 5,456 5,456 5,458 5,481 5,483 5,483 5,457 5,418 5,441 # of Tx Packets / Gateway 180 180 180 180 180 180 180 180 180 180 180 180 180 180 180 180 180 Total Processing Delay (µs) 957,337 957,608 957,608 962,608 962,714 962,879 967,363 967,469 982,120 982,120 982,419 986,613 986,912 986,985 982,330 975,151 979,464 Table 5.19 - The simulation results of a WMAN topologies experiment that has 10 gateways. The number of meter data packets put in a sending UDP packet was changed until the UDP packet is fragmented. In the above experiment, the number of UDP packets sent in one second is very close to the maximum WiMAX frames can send in one second (about 200), that will cause the network being overloaded when the UDP packets fragmented. For example, the number of received packets is less than the number of sent packets when there are 16 or 17 meter data packets in a UDP packet. 5.3.4 The WAN Simulation Results 5.3.4.1 Experiment 1: The WAN Star Topology With 3 BSs Topology Configuration 64 Link capacity: 10Mbps Medium Transmission Delay: 3.3 us/km for optical fiber, cable length is a random number BSs are connected to the Data Center in the Star topology Distance between DC and BS: in range from 1 km to 100km Connection mode: Point-to-point topology NS-3 Simulation Time in Sec 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 # of Packets Tx 0 5,400 5,400 5,400 5,400 5,400 5,400 5,400 5,400 5,400 5,400 5,400 5,400 5,400 5,400 5,400 5,400 5,400 5,400 5,400 # of Packets Rx 0 5,397 5,400 5,400 5,400 5,400 5,400 5,400 5,400 5,400 5,400 5,400 5,400 5,400 5,400 5,400 5,400 5,400 5,400 5,400 Avg Tx (µs) 0 293 293 293 293 293 293 293 293 293 293 293 293 293 293 293 293 293 293 293 Delay # of Tx Packets / BS 1,800 1,800 1,800 1,800 1,800 1,800 1,800 1,800 1,800 1,800 1,800 1,800 1,800 1,800 1,800 1,800 1,800 1,800 1,800 1,800 Total Processing Delay (µs) 0 527,470 527,470 527,470 527,470 527,470 527,470 527,470 527,470 527,470 527,470 527,470 527,470 527,470 527,470 527,470 527,470 527,470 527,470 527,470 Table 5.20 – The simulation results of a WAN Point-to-point Star topology with three base stations. The statistical data are in one second period. 65 The initialization period is in first two seconds. From the third second, the WAN network has the average delay at 293 µseconds. The star topology has the point-to-point connections between data center and base stations. This WAN network can provide a very high bandwidth. 5.3.4.2 Summary of the Experiments for WAN Improved Design # of Base Stations 1 2 3 4 5 6 7 Tx Packets 1,800 3,600 5,400 7,200 9,000 10,800 12,600 Rx Packets 1,800 3,600 5,400 7,200 9,000 10,800 12,600 # of Meter Data Packets / Packet 15 15 15 15 15 15 15 Total Tx Meter Packets 27,000 54,000 81,000 108,000 135,000 162,000 189,000 Total Rx Meter Packets 27,000 54,000 81,000 108,000 135,000 162,000 189,000 Avg. Tx Delay (µs) 260 291 293 293 252 248 214 # of Tx Packets / BS 1,800 1,800 1,800 1,800 1,800 1,800 1,800 Total Processing Delay (µs) 468,070 524,500 527,470 527,470 453,814 447,280 385,756 Table 5.21 – The WAN simulation results. The statistical data in each row are the results of one simulation experiment. Cable Length (km) 1 10 20 30 40 50 60 70 80 90 100 # of Meter # of Rx Data # of Tx Packet Packets / Packets s Tx Packet 1,800 1,800 15 1,800 1,800 15 1,800 1,800 15 1,800 1,800 15 1,800 1,800 15 1,800 1,800 15 1,800 1,800 15 1,800 1,800 15 1,800 1,800 15 1,800 1,800 15 1,800 1,800 15 Total Tx Total Rx Avg. Tx Meter Meter Delay Data Data Packets Packets (µs) 27,000 27,000 6 27,000 27,000 36 27,000 27,000 69 27,000 27,000 102 27,000 27,000 135 27,000 27,000 168 27,000 27,000 201 27,000 27,000 234 27,000 27,000 267 27,000 27,000 300 27,000 27,000 333 Total Processing Delay (µs) 10,690 64,150 123,550 182,950 242,350 301,750 361,150 420,550 479,950 539,350 598,750 Table 5.22 - The of simulation results of the WAN topologies experiments that have one base station connected to the data center. The length of the optical fiber cable was changed to evaluate the total processing delay at a BS. 66 5.4 Simulation Results Analysis 5.4.1 The WLAN Simulation Results Analysis The Figure 5.1 show the simulation results in every one NS-3 second for the WLAN topology that has 50 smart meters. Fifty UDP packets that sent from fifty smart meters, received at the AP with the average transmission delay of 10 milliseconds. We can see that, the delay time of a package and the total transmission delay converges to 10 milliseconds. WLAN (IEEE 802.11a) w/ 50 SMs Simulation 55 12,000 50 10,000 45 40 Packets 30 6,000 25 20 4,000 15 10 2,000 5 0 0 0 2 4 6 8 10 12 14 16 18 20 22 NS-3 Sim Seconds Packets Tx Packets Rx Avg Tx Delay (us) Total Processing Delay (us) Figure 5.11 - The simulation results in every one second for the WLAN Infrastructure mode topology with one AP and fifty SMs in the network. Time (us) 8,000 35 67 120 25,000 100 20,000 Packets 80 15,000 60 10,000 40 Time (us) WLAN (IEEE 802.11a) w/ variable SMs Simulation 5,000 20 0 0 0 20 40 60 80 100 120 SMs Packets Tx Packets Rx Total Processing Delay (us) Figure 5.12 – The simulation results for the WLAN infrastructure mode topology. The number of SMs is assigned from the one to one hundred in the experiments to evaluate the changing of the total processing delay at the SMs. Figure 5.2 shows the simulation results for the WLAN infrastructure mode topology. The number of SMs is assigned from the one to one hundred in the experiments to evaluate the changing of the total processing delay at the SMs. The number of the UDP packets sent and received in every one second for the simulation duration versus the number of the SMs in many different simulation scenarios. The total processing delay is also plotted on the chart. We can see that, the network has successfully transmitted the UDP packets in every one second from the senders (or smart meters) to the receiver (or AP). Moreover, we can see that the total processing delay increases linearly with the number of smart meters. The total processing delay at one smart meter is below the one second 68 threshold when the number of smart meters in the WLAN topology is equal or less than seventy. 5.4.2 The WNAN Simulation Results Analysis WNAN (IEEE 802.11s Mesh) w/ 9 APs Simulation 500 300,000 450 250,000 400 200,000 300 250 150,000 200 Time (us) Packets 350 100,000 150 100 50,000 50 0 0 0 20 40 60 80 100 NS-3 Sim Seconds Packets Tx Packets Rx Avg Tx Delay (us) Total Processing Delay (us) Figure 5.13 – The simulation results in every one second for the WNAN 3x3 mesh topology with nine APs and one GW. AP sent 50 packets in every one second to the GW. Figure 5.14 shows simulation results in every one second for the WNAN 3x3 mesh topology with nine APs and one GW. AP sent 50 packets in every one second to the GW. There are total 450 UDP packets sent to the GW in every second. The number of sent and received UDP packets is equal in every second. We also see that, the total transmission delay converge to 500 millisecond. 69 WNAN (IEEE 802.11s Mesh) w/ variable APs Simulation 500 30,000 25,000 400 300 15,000 200 Time (us) Packets 20,000 10,000 100 5,000 0 0 0 1 2 3 4 5 6 7 8 9 APs Packets Tx Avg. Packets Rx Total Processing Delay (us) Figure 5.15 - The simulation results of the WNAN 3x3 grid topology with nine MRs and one GW in the network. Figure 5.4 shows the simulation results for the WNAN 3x3 grid topology. There are nine MRs and one GW in the network. The number of APs is assigned from the one to nine in the experiments to evaluate the changing of the total processing delay at the APs. The number of the UDP packets sent and received in every one second for the simulation duration versus the number of the APs in many different simulation scenarios. The total processing delay is also plotted on the chart. We can see that, the network has successfully transmitted the UDP packets in every one second from the senders (or APs) to the receiver (or GW). 70 Moreover, we can see that the total processing delay increases rapidly with the number of APs. The line of total processing time likes a parabolic arc. That is due to the increasing hop count on the mesh routing path [AWW05, HWC08]. The total processing delay at one AP for sending fifty 20-bytes packets is below the one second threshold. 5.4.3 The WMAN Simulation Results Analysis 1810 1,200,000 1805 1,000,000 1800 800,000 1795 600,000 1790 400,000 1785 200,000 1780 Time (us) Packets WMAN (IEEE 802.16d) w/ 10 GWs Simulation 0 0 5 10 15 20 25 30 35 NS-3 Sim Seconds Packets Tx Packets Rx Avg Tx Delay (us) Total Processing Delay (us) Figure 5.16 - The simulation results of WMAN point-to-multipoint topology with one BS and ten GWs in the network. GW sent 180 packets in every one second to the BS. Figure 5.5 shows the simulation results in every one second for the WMAN point-tomultipoint topology. There are one BS and ten GWs in the network. GW sent 180 packets in every one second to the BS. There are 1,800 UDP packets sent to the BS in every second. The number of received packets are not exactly equal the number of sent packets in every second. The difference between them is between -5 and 5 packets. If a packet 71 does not arrive in the same second, it will arrive in the next second. The average delay of a packet that is about 5.5 milliseconds, can validate this hypothesis. We also see that, the total transmission delay converges to 930 milliseconds. 2,000 1,800 1,600 1,400 1,200 1,000 800 600 400 200 0 1,000,000 990,000 980,000 970,000 960,000 950,000 940,000 930,000 920,000 0 1 2 3 4 5 6 7 8 9 Time (us) Packets WMAN (IEEE 802.16d) w/ variable GWs Simulation 10 GWs Packets Tx Avg. Packets Rx Total Processing Delay (us) Figure 5.17 - The simulation results for the WMAN topology. The number of GWs is assigned from the one to ten in the experiments to evaluate the changing of total processing delay at the GWs. In the Figure 5.6 , the number of the UDP packets sent and received in every one second for the simulation duration versus the number of GWs for different simulation experiments. The total processing delay is also plotted on the chart. We can see that, the network has successfully transmitted the UDP packets in every one second from the senders (or GWs) to the receiver (or BS). Moreover, we can see that the total processing delay is between 930 and 960 milliseconds. It does not increase with the number of the GWs. This is due to the 72 WiMAX network or 802.16d standard has a fixed frame time (5ms) that is independent to the number of the subscribers. Impact On The Network Performance By Aggregating Meter Data Figure 5.7 shows the simulation results for the WMAN point-to-multipoint topology from many experiments. There was one BS and ten GWs in the network. GW sent 180 packets to the BS in every second. The number of meter data packets put in a transmitted UDP packet was assigned from the one to seventeen packets to evaluate the changing of total processing delay at the BSs in the experiments. Figure 5.7 shows the improvement of network performance when the number of meter data packets are aggregated in a transmitted UDP packet or the length of loaded data in one WiMAX frame. The number of meter data packet was increased until the network going to the overloaded state. As we can see on the chart, when the number of meter packets is less than 16, the network successfully transmitted all of the UDP packets. This is due to the sending UDP packet that contains a designated number of meter data packets, is not fragmented in the transmission. Moreover, the traffic application was programmed to send out in every second the number of UDP packets that can be delivered completely by the network in one second. However, the network is overloaded when the number of embedded meter data packets is equal or greater than 16. This is due to the UDP packets were fragmented in the transmission. That caused number of received packets in one second less than the number of sent packets. As a result, the average transmission delay of a packet was increased. 73 35,000 990,000 30,000 985,000 25,000 980,000 20,000 975,000 15,000 970,000 10,000 965,000 5,000 960,000 0 955,000 0 2 4 6 8 10 12 14 16 Time (us) Packets WMAN (IEEE 802.16d) w/ 10 GWs, various sub-packet lengths simulation 18 Number of meter data packets Packets Tx Packets Rx Total Sub Packet Tx Total Sub Packet Rx Total Processing Delay (us) Figure 5.18 - Impact on the network performance by aggregating meter data. 5.4.4 The WAN Simulation Results Analysis 74 WAN (Star Topology) w/ 3 BSs Simulation 5,401 600,000 5,400 500,000 5,400 400,000 5,399 300,000 5,398 200,000 5,398 100,000 5,397 5,397 0 0 5 10 15 20 25 NS-3 Sim Seconds Packets Tx Packets Rx Avg Tx Delay (us) Total Tx Delay (us) Figure 5.19 - The simulation results in every one second for the WAN star topology with DC and three BSs in the network. BS sent 1,800 packets in every one second to the DC. Figure 5.20 shows the simulation results in every one second for the WAN star topology. There are one DC and three BSs in the network. The connection between the DC and BS is point-to-point. BS sent 1,800 packets in every one second to the DC. There are total of 5,400 packets sent to the DC in every second. The number of sent and received UDP packets are equal in every second. We also see that, the total transmission delay converges to 520 milliseconds. Time (us) Packets 5,399 75 WAN (Star Topology) w/ various BSs simulation 200,000 600,000 180,000 500,000 160,000 400,000 120,000 100,000 300,000 80,000 200,000 60,000 40,000 100,000 20,000 0 0 0 1 2 3 4 5 6 7 8 BSs Packets Tx Packets Rx Total Meter Packet Tx Total Meter Packet Rx Total Processing Delay (us) Figure 5.21 - The simulation results for the WAN star topology from many experiments. Figure 5.22 shows the simulation results for the WAN star topology from many experiments. The number of BSs was assigned from the one to seven to evaluate the changing of total processing delay at the BSs in the experiments. The number of the UDP packets sent and received in every one second for the simulation duration versus the number of BSs for different simulation experiments. The total processing delay is also plotted on the chart. We can see that, the network has successfully transmitted the UDP packets in every one second from the senders (or BSs) to the receiver (or the data center). Time (us) Packets 140,000 76 Moreover, we can see that the total processing delay is independent from the number of the BSs. This is due to the BSs were connected to the data center in the point-to-point connections. The network can transmit over 180,000 meter data packets that sent from seven BSs, and the total processing time at each BS is less than 600 milliseconds. However, the average delay is affected by the distribution of the BSs around the data center. WAN (Star Topology) w/ various cable lengths simulation 30,000 700,000 25,000 600,000 Packets 400,000 15,000 300,000 10,000 200,000 5,000 100,000 0 0 0 20 40 60 80 100 120 Cable Length Packets Tx Packets Rx Total Meter Packet Tx Total Meter Packet Rx Total Processing Delay (us) Figure 5.23 - The simulation results for the WAN star topology with one DC and one BS. The length of the optical fiber cable was assigned from the one to 100 kilometers. Figure 5.24 shows the simulation results for the WAN star topology from many experiments. There was one DC and one BS in the network. BS sent 1,800 packets to the Time (us) 500,000 20,000 77 DC in every second. The length of the optical fiber cable that connects the DC and BS was assigned from the one to 100 kilometers to evaluate the changing of total processing delay at the BS in the experiments. We can see that the total processing time was linearly increased with the length of the optical fiber cables that connect the BSs and the data center. Chapter 6 Lessons Learned 6.1 The Development of SG-WIP Planning Tool SG-WIP web application is a Google Maps mashup. The developing process is followed the steps Requirement Spec, Design Spec, Coding and Testing, Deployment. One of the most challenges of the Web application development process is the debugging task. The debugging web pages have to be opened in a Web browser that supports the debugging tool, such as the Developer Tools in the Microsoft Internet Explorer. However, the debugging tool of the Web browser can only debug the scripts that run on the client machine, i.e. JavaScript. The Google Maps mashup SG-WIP uses PHP language at the Web server and JavaScript at the client browser. When a web page is running at the client browser, the server scripts of that web page have been executed on the web server before it is sent to the browser. So the debugging tool at the web browser can not be used for the server scripts. Because we can not interactively debug the server scripts from the browser tools, we need to log the running information of the server scripts for the program tracing. We also converted the PHP server pages into the 79 executable programs and ran them on the server to test and debug the server scripts much easier. Another difficulty is the collecting of the housing unit geographical locations for the residential density analysis, and the street light poles geographical locations for the planning of the wireless antennae. We have the helps of CSU to get needed infrastructure information for planning the AMI communication network in the simulation process. Although the infrastructure information collection was a sophisticate process because there were constrains on the data release policy from CSU, the topology planning tool has the real world geographical location of the housing units and the streetlight poles to display and process. Thus, the simulation network model is designed closer to the real world. 6.2 The Development of Smart Grid Simulation Model This thesis employed the modern wireless network technologies such as WiMAX and Wi-Fi. Network simulation tools help the network researchers evaluating their solutions, designing new network devices or communication protocols. We have used two network simulation software NS-3 and NCTUns [NS3, NCTU01] in researching and developing the WiMAX/Wi-Fi communication infrastructure for AMI. NCTUns has a great GUI that allows visually building the network topologies, simulating, and animating the network simulation. We used the NCTUns to quickly construct the simulation scenarios in the thesis proposal development phase. NS-3 was used to construct the complicated parameterized wireless network model in this thesis. There are hundreds thousand of the wireless nodes (smart meters) simulated using the NS-3 simulator. One of the greatest features of NS-3 is providing the programmable 80 network modules such as WiMAX, Wi-Fi, CSMA under the Object Oriented Programming (OOP) style in C++ language. However, NS-3 is still in developing phase. There are not much help documents published. I have found a bug in the WiMAX module that limits the number of the Subscriber Stations to under twenty nodes in any simulation scenario. More information about this bug is following the URL: http://www.nsnam.org/bugzilla/show_bug.cgi?id=1025 NS-3 is free and open source project. It has been quickly accepted and supported by the network research community. 6.3 The Simulation Process in NS-3 6.3.1 The Initialization Phase of Wireless Networks NS-3 wireless network models such as WiMAX, and Wi-Fi perform the Initialization phase at the starting of simulation duration. The time length of the initialization phase is dependent on the network type, for example, the WiMAX topology with one BS and ten SSs needs six seconds. The simulation experiment designs should take this fact into account when making decision about the start time of the network traffic applications. 6.3.2 The Bugs in NS-3 Module Code NS-3 is still in the development phase. Whether you like it or not, the bugs existing in the source code, and they will affect to your simulation experiments. As I mentioned about the bug in the WiMAX module, I has sent the bug report to the authors of the WiMAX module and immediately received their responses. 81 However, the open source software like NS-3 has been rapidly developing and receiving the supports from the network research and development community. When there is a bug reported, there are hundreds of the researchers around the world who can help solving it immediately. As a result, the open source software NS-3 simulator will be more and more reliable and helpful. Chapter 7 Simulation Limitations and Future Work The proposed network model is implemented as a parameterized simulator in NS-3. There are many featured variables that were used as the input of the simulator, such as number of network device nodes, distance between nodes, data rates, etc. However, there are some limitations that were not modeled in the simulator, for example, the height of the nodes, geographical locations. 7.1 Display Simulation Results on the SG-WIP Planning Tool In this thesis, the designed simulation experiences are based on the analysis of the household density in the service areas. Because the real world network topologies are complicated, in the simulation, we used only one featured simulation scenario designed for a specific kind of the network topology i.e. WAN, WMAN, WNAN, and WLAN. 83 We can use our SG-WIP planning tool to edit the network topologies, simulation the trial topologies, and display the simulation results on the GUI display. Then, we can compare the different planned topologies to select the better one. The SG-WIP planning tool can be extended to export the network topologies and planning results including the placement of antennae as a file. The NS-3 network model can be modified to accept an arbitrary network topology as an input. Then, the real world topologies can be simulated with the NS-3 network model and produce simulation results for further analysis. 7.2 Alternative Method Application Simulation for Network Traffic The alternative method for application traffic simulation is the sending packet at a random time. The packets are randomly sent from the smart meters to the data center through the communication infrastructure. When the packets are transmitted in the communication infrastructure, they will be logged in the trace files on the intermediate network nodes along the routing path. One of the advantages of this traffic simulation method is the randomly sending time of the packets, which makes the simulation closer to the real world. However, in the complicated simulation scenarios, such as in this thesis, the alternative method needs more computing resources such as CPU time for random number generation, memory space, storage space for trace files. 7.3 Improve the Antenna Placement Algorithm 84 The antenna placement algorithm in the SG-WIP application should take into account the network availability property when it searches for the antenna position. For network availability improvement, the antenna will cover not only the corresponding network area, but also its neighborhood networks. If the antenna of a network is down, the working antenna in one of the neighborhood network areas will become the corresponding one. 7.4 Store the Real-time Meter Data in the Database Management System (DBMS) DBMS is needed to store the real-time meter data for efficient data access and management. The real-time metering collection process may pass a large amount of meter data to the DBMS in less than one second. It opens an opportunity for a research of the DBMS for the real-time meter data. The possible solution can employ the real-time DBMS technologies, and the distributed computing technologies. 7.5 Evaluate the Performance of the Network Model with the AMI real-time Demand Response Applications Demand response is one of the important goals of the AMI deployment. In contrast to the metering collection, the demand response supporting applications will request the meter data from the data center for the consumer’s demand analysis. Then the demand response applications can help the consumers optimize their energy usage. Although this subject is out of the scope of this thesis, it can contribute to the AMI researcher community another interesting performance evaluation of the WMN WiMAX/Wi-Fi infrastructure. Chapter 8 Conclusion AMI is being implemented by many utilities around the world. AMI contributes the benefits not only to the utilities but also to the consumers. AMI real-time meter data collection can give the utilities and consumers the ability to access the real-time meter data. Consumers are benefits from the sharing real-time meter data because they can monitor and actively adjust their demand of electric, gas, and water to save money. Utilities are benefits from the real-time meter data because they can use the real-time meter data to improve the quality of load profile charts, and load prediction. So the utilities can save the fuel usage of power plants and reduce the price of electricity. Many utilities have implemented the AMI wireless infrastructures for collecting meter data automatically. However, most of the deployed wireless infrastructure did not support or have not supported yet the real-time meter data collection. The intervals for meter data collection are typically higher than one minute. The current meter data collecting period is often in the range between fifteen and forty five minutes. 86 One of the main contributions of this thesis is the development a methodology for measuring the performance of the hybrid WiMAX/Wi-Fi communication infrastructure for the real-time metering data collection. The second contribution is the development of a software tool SG-WIP for planning and designing the AMI wireless infrastructure using the real utility light poles and meters GIS data from the city of Colorado Springs, Colorado. The third contribution is the development of a simulator SG-SIM to evaluate the performance of the hybrid WiMAX/Wi-Fi AMI network. We proposed a parameterized WiMAX/Wi-Fi network model and implemented it in the NS-3 platform. Experiments were conducted using the network simulation process, including the WLAN (Wi-Fi) simulation, the WNAN (Wi-Fi Mesh) simulation, the WMAN (WiMAX) simulation, and the WAN (optical fiber point-to-point connection) simulation. The simulation results show that the proposed WiMAX/Wi-Fi WMN infrastructure can transport the meter data from 160,000 smart meters in the CSU service areas to the data center in one second. From the simulation result analysis, we can conclude that the high scalability property of WiMAX/Wi-Fi WMN helps flexibly extend the coverage area of the AMI wireless infrastructure without degrading the network performance. This thesis provides the utilities an AMI wireless communication infrastructure solution that employs the WiMAX/Wi-Fi WMN architecture for real-time metering data collection. The proposed WiMAX/Wi-Fi infrastructure allows the utilities deploying an AMI wireless communication infrastructure not only at low cost of installation and maintenance but also with high performance, scalability, and security. 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[IEEE16] IEEE Standard 802 Part 16: Air Interface for Broadband Wireless Access Systems, 2009. [IEEE11s] IEEE, “Draft amendment: ESS mesh networking”, IEEE P802.11s Draft 1.00, November 2006. 88 [Moh01] Prasant Mohapatra, Lecture “Wireless Mesh Networks”, Department of Computer Science University of California, Davis. [AWW05] I. F. Akyildiz, X. Wang, and W. Wang, "Wireless Mesh Networks: A Survey," Computer Networks Journal (Elsevier), vol. 47, no. 4, pp. 445-487, Mar. 2005. [Kri01] Srini Krishnamurthy, “Smart AMI Network Solutions Enable the Smart Grid”, ElectricEnergyOnline.com, <http://www.electricenergyonline.com/?page=show_article&mag=55&article=395> [Met01] MetroFi, <http://en.wikipedia.org/wiki/MetroFi> [Sky01] SkyPilot, <http://skypilot.trilliantinc.com> [Eka01] EkaNet, <http://www.ekasystems.com/ekanet.htm> [AWW05] I. F. Akyilidz, X. Wang, and W. Wang, “Wireless Mesh Networks: A Survey” in Elsevier Computer Networks Journal, vol. 47, March 2005, pp. 445–487. [JS03] J. 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Raychaudhuri, "Performance and Scalability of SelfOrganizing Hierarchical Ad-Hoc Wireless Networks," Proceedings of the IEEE Wireless Communications and Networking Conference (WCNC'04), Atlanta, GA. March 2004, pp. 132-137. 90 [HWC08] J. H. Huang, L. C. Wang, C. J. Chang, “Wireless Mesh Network: Architecture and Protocols”, chapter title “Architectures and Deployment Strategies for Wireless Mesh Networks”, Springer 2008. [OSI] “OSI Model”, <http://en.wikipedia.org/wiki/OSI_model> [Wimax] WiMAX community, <http://www.wimax.com> [NS3] The Network Simulator Ns-3, <http://www.isi.edu/nsnam/ns/> [NCTU01] NCTUns 6.0 Network Simulator and Emulator, <http://nsl.csie.nctu.edu.tw/nctuns.html> [NCTU02] “The Protocol Developer Manual for the NCTUns 6.0”, Network and System Laboratory, Department of Computer Science, National Chiao Tung University, Taiwan 2010. [HSWL07] S.M. Huang, Y.C. Sung, S.Y. Wang, and Y.B. Lin, “NCTUns Simulation Tool for WiMAX Modeling,” Third Annual International Wireless Internet Conference, October 22 – 24, 2007, Austin, Texas, USA. (EI and ISI indexed, sponsored by ICST, ACM, and EURASIP) [SH06] N.B. Salem and J.P. Hubaux, "Securing Wireless Mesh Networks," Wireless Comm., vol. 13, no. 2, 2006, pp. 50–55. [PSC06] Michael Purvis, Jeffrey Sambells, and Cameron Turner, “Beginning Google Maps Applications with PHP and Ajax”, Apress, 2006. [Goog01] Google Maps JavaScript V3, <http://code.google.com/apis/maps/documentation/javascript/> Appendix A SG-WIP User Manual A.1 Installation A.1.1 System Requirements Apache Web Server PHP module MySQL Server A.1.2 The Database The database is named “sgwip”. There is a user account name “sgwip” created for accessing the database from the Web application “SG-WIP”. The “sgwip” account need proper access permission to allow the Web application “SG-WIP” access the tables in the database. A.1.3 The SG-WIP Application The URL of the SG-WIP for downloading is at http://cs.uccs.edu/~gsc/pub/master/phuynh/src/sgwip.zip The Web application SG-WIP is installed on the Apache Web server. For example the application was install on the local web server as the following Linux Fedora file system: /usr/share/sgwip 92 Figure A.7 - The SG-WIP application was installed on the Apache web server 93 A.2 The GUI Operations A.2.1 Opening the Home Page In the Web browser, open the following URL: http://scad.eas.uccs.edu/sgwip/wan.html Figure A.8 - The home page of SG-WIP 94 A.2.2 Generating the WAN Topology Click the menu item “New” Wait for the GUI being generated and displayed on the Google maps (this process may take many seconds to finish the job) Figure A.9 - The WAN topology has twelve WiMAX base stations Click the menu item “WAN” 95 Note: To return back to the WAN topology in the current path of the topology exploration A.2.3 Generating the MAN Topology Click on the corresponding rectangle from the WAN topology GUI. A rectangle is a Google Maps overlay object that represents for a network topology. Wait for the network topology GUI being generated and displayed on the Google Maps (this process may take many seconds to finish the job) Click the menu item “MAN” Figure A.10 - The WMAN topology has WiMAX BS, and WiMAX/Wi-Fi Gateways. Note: To return back to the MAN topology in the current path of the topology exploration 96 A.2.4 Generate the NAN Topology Click on the corresponding rectangle from the MAN topology GUI. A rectangle is a Google Maps overlay object that represents for a network topology. Wait for the network topology GUI being generated and displayed on the Google maps (this process may take many seconds to finish the job) Figure A.11 The WNAN topology has WiMAX/Wi-Fi gateway, and Mesh routers/Access Points. Click the menu item “NAN” Note: To return back to the NAN topology in the current path of the topology exploration 97 A.2.5 Generating the LAN Topology Click on the corresponding rectangle from the NAN topology GUI. A rectangle is a Google Maps overlay object that represents for a network topology. Wait for the network topology GUI being generated and displayed on the Google maps (this process may take many seconds to finish the job) Figure A.12 - The WLAN topology includes Wi-Fi Access Point, and Smart meters. Click the menu item “LAN” 98 Note: To return back to the LAN topology in the current path of the topology exploration A.2.6 Changing the Antennae Location of Network Devices The antennae of the wireless network devices such as WiMAX base station, WiMAX/Wi-Fi gateway, or AP/Mesh Router can be re-located to a better place within the topology. Click the menu item “On-Change-Antenna-Loc” Click the changed Antenna Navigate to the destination network topology where there is a hanging object such as street light poles, or the housing/building unit. Click the target hanging object to select a new location for the antenna. Appendix B SG-SIM Simulator Running Examples B.1 The LAN Simulation Examples [phuynh@scad ns-3.9]$ ./waf --run "examples/sg-sim/sm-ap-sim --nbSM=1 --statisticstart=4" Waf: Entering directory `/root/ns-allinone-3.9/ns-3.9/build' Waf: Leaving directory `/root/ns-allinone-3.9/ns-3.9/build' 'build' finished successfully (1.273s) 1 0 0 0ns 2 0 0 0ns 3 1 1 6082144ns 4 1 1 1540048ns 5 1 1 1540048ns 6 1 1 1540048ns 7 1 1 1540048ns 8 1 1 1540048ns 9 1 1 1540048ns 10 1 1 1540048ns Avg. Tx packets/second:1 Avg. Rx packets/second:1 Avg. Tx delay (milliseconds):1 [phuynh@scad ns-3.9]$ ./waf --run "examples/sg-sim/sm-ap-sim --nbSM=10 --statisticstart=4" Waf: Entering directory `/root/ns-allinone-3.9/ns-3.9/build' Waf: Leaving directory `/root/ns-allinone-3.9/ns-3.9/build' 'build' finished successfully (1.272s) 1 0 0 0ns 2 0 0 0ns 3 10 10 66400682ns 4 10 10 19814024ns 100 5 10 10 19277024ns 6 10 10 19915025ns 7 10 10 20013025ns 8 10 10 19392024ns 9 10 10 20553025ns 10 10 10 20255025ns Avg. Tx packets/second:10 Avg. Rx packets/second:10 Avg. Tx delay (milliseconds):19 [phuynh@scad ns-3.9]$ ./waf --run "examples/sg-sim/sm-ap-sim --nbSM=100 --statisticstart=4" Waf: Entering directory `/root/ns-allinone-3.9/ns-3.9/build' [ 519/1090] cxx: examples/sg-sim/sm-ap-sim.cc -> build/debug/examples/sg-sim/sm-apsim_3.o [1090/1090] cxx_link: build/debug/examples/sg-sim/sm-ap-sim_3.o build/debug/examples/sg-sim/sg-onoff-application_3.o -> build/debug/examples/sgsim/sm-ap-sim Waf: Leaving directory `/root/ns-allinone-3.9/ns-3.9/build' 'build' finished successfully (4.568s) 1 0 0 0ns 2 0 0 0ns 3 100 100 688476554ns 4 100 100 197641136ns 5 100 100 195392137ns 6 100 100 199219136ns 7 100 100 197660136ns 8 100 100 197337137ns 9 100 100 201163137ns 10 100 100 201171136ns Avg. Tx packets/second:100 Avg. Rx packets/second:100 Avg. Tx delay (milliseconds):198 101 B.2 The NAN Simulation Examples [phuynh@scad ns-3.9]$ ./waf --run "examples/sg-sim/ap-gw-sim --data-rate=16kbps -time=30 --access-points=1 --x-size=1 --y-size=1 --interfaces=4 --step=300 --statisticstart=12" Waf: Entering directory `/root/ns-allinone-3.9/ns-3.9/build' Waf: Leaving directory `/root/ns-allinone-3.9/ns-3.9/build' 'build' finished successfully (1.247s) 1 99 99 0ns 2 100 100 0ns 3 100 100 0ns 4 100 100 0ns 5 100 100 0ns 6 100 100 0ns 7 100 100 0ns 8 100 100 0ns 9 100 100 0ns 10 100 100 0ns 11 100 100 0ns 12 100 100 0ns 13 100 100 0ns 14 100 100 0ns 15 100 100 0ns 16 100 100 0ns 17 100 100 0ns 18 100 100 0ns 19 100 100 0ns 20 100 100 0ns 21 100 100 0ns 22 100 100 0ns 23 100 100 0ns 24 100 100 0ns 25 100 100 0ns 26 100 100 0ns 27 100 100 0ns 28 100 100 0ns 29 100 100 0ns 30 100 100 0ns Avg. Tx packets/second:100 Avg. Rx packets/second:100 Avg. Tx delay (milliseconds):0 102 [phuynh@scad ns-3.9]$ ./waf --run "examples/sg-sim/ap-gw-sim --data-rate=16kbps -time=30 --access-points=4 --x-size=2 --y-size=2 --interfaces=4 --step=300 --statisticstart=12" Waf: Entering directory `/root/ns-allinone-3.9/ns-3.9/build' Waf: Leaving directory `/root/ns-allinone-3.9/ns-3.9/build' 'build' finished successfully (1.252s) 1 396 380 103982400ns 2 400 400 874410ns 3 400 400 856410ns 4 400 400 866410ns 5 400 400 902410ns 6 400 400 211025206ns 7 400 400 41414ns 8 400 400 41414ns 9 400 400 41414ns 10 400 400 41414ns 11 400 400 894996ns 12 400 400 41414ns 13 400 400 41414ns 14 400 400 41414ns 15 400 400 41414ns 16 400 400 1273064ns 17 400 400 41414ns 18 400 400 41414ns 19 400 400 41414ns 20 400 400 41414ns 21 400 400 1223822ns 22 400 400 41414ns 23 400 400 41414ns 24 400 400 41414ns 25 400 400 41414ns 26 400 400 1135480ns 27 400 400 41414ns 28 400 400 41414ns 29 400 400 41414ns 30 400 400 41414ns Avg. Tx packets/second:400 Avg. Rx packets/second:400 Avg. Tx delay (milliseconds):0 [phuynh@scad ns-3.9]$ ./waf --run "examples/sg-sim/ap-gw-sim --data-rate=16kbps -time=30 --access-points=6 --x-size=2 --y-size=3 --interfaces=4 --step=300 --statisticstart=12" Waf: Entering directory `/root/ns-allinone-3.9/ns-3.9/build' 103 Waf: Leaving directory `/root/ns-allinone-3.9/ns-3.9/build' 'build' finished successfully (1.272s) 1 594 570 106987685ns 2 600 600 1632058ns 3 600 600 1441058ns 4 600 600 1642057ns 5 600 600 1837642ns 6 600 372 205857651ns 7 600 828 1639371823ns 8 600 600 1255824ns 9 600 600 1337824ns 10 600 600 1255824ns 11 600 600 3000281ns 12 600 600 1382824ns 13 600 600 2284941ns 14 600 600 321064ns 15 600 600 321064ns 16 600 600 2713123ns 17 600 600 1274290ns 18 600 600 993955ns 19 600 600 319412ns 20 600 600 319412ns 21 600 600 989117ns 22 600 600 924711ns 23 600 600 2113878ns 24 600 600 319412ns 25 600 600 319412ns 26 600 600 2505356ns 27 600 600 808770ns 28 600 600 2939821ns 29 600 600 318997ns 30 600 600 318997ns Avg. Tx packets/second:600 Avg. Rx packets/second:600 Avg. Tx delay (milliseconds):1 [phuynh@scad ns-3.9]$ ./waf --run "examples/sg-sim/ap-gw-sim --data-rate=16kbps -time=30 --access-points=9 --x-size=3 --y-size=3 --interfaces=4 --step=300 --statisticstart=12" Waf: Entering directory `/root/ns-allinone-3.9/ns-3.9/build' Waf: Leaving directory `/root/ns-allinone-3.9/ns-3.9/build' 'build' finished successfully (1.272s) 1 891 738 119623509ns 2 900 901 1001745189ns 104 3 900 900 2325664ns 4 900 900 2484352ns 5 900 853 4331459ns 6 900 420 207812067ns 7 900 652 1639814429ns 8 900 588 206033357ns 9 900 918 210843707ns 10 900 900 1398469ns 11 900 900 2194660ns 12 900 900 3773257ns 13 900 900 3320283ns 14 900 900 2380716ns 15 900 900 832062ns 16 900 900 4425319ns 17 900 900 2087537ns 18 900 900 3081115ns 19 900 900 2029719ns 20 900 900 1498443ns 21 900 900 3893531ns 22 900 900 2187714ns 23 900 900 2989236ns 24 900 900 955469ns 25 900 900 1240705ns 26 900 900 2895261ns 27 900 900 2384426ns 28 900 900 4603544ns 29 900 900 821468ns 30 900 900 853298ns Avg. Tx packets/second:900 Avg. Rx packets/second:900 Avg. Tx delay (milliseconds):2 105 B.3 The MAN Simulation Examples [phuynh@scad ns-3.9]$ ./waf --run "examples/sg-sim/gw-bs-sim --nbSS=1 --duration=30 --statistic-start=10" Waf: Entering directory `/root/ns-allinone-3.9/ns-3.9/build' Waf: Leaving directory `/root/ns-allinone-3.9/ns-3.9/build' 'build' finished successfully (1.291s) 1 0 0 0ns 2 0 0 0ns 3 0 0 0ns 4 0 0 0ns 5 0 0 0ns 6 0 0 0ns 7 900 892 12140304ns 8 900 901 11695508ns 9 900 901 11917504ns 10 900 902 12139374ns 11 900 900 12139064ns 12 900 901 12138628ns 13 900 901 11916180ns 14 900 891 11915853ns 15 900 910 12137866ns 16 900 892 12137472ns 17 900 902 11915024ns 18 900 900 12136936ns 19 900 901 11914387ns 20 900 901 11913951ns 21 900 902 12136048ns 22 900 900 12135696ns 23 900 900 12135260ns 24 900 901 12135034ns 25 900 892 11912460ns 26 900 901 11912276ns 27 900 901 12134104ns 28 900 902 12133794ns 29 900 900 11689065ns 30 900 901 11911061ns Avg. Tx packets/second:900 Avg. Rx packets/second:900 Avg. Tx delay (milliseconds):12 [phuynh@scad ns-3.9]$ ./waf --run "examples/sg-sim/gw-bs-sim --nbSS=5 --duration=30 --statistic-start=10" Waf: Entering directory `/root/ns-allinone-3.9/ns-3.9/build' 106 Waf: Leaving directory `/root/ns-allinone-3.9/ns-3.9/build' 'build' finished successfully (1.261s) 1 0 0 0ns 2 0 0 0ns 3 0 0 0ns 4 0 0 0ns 5 0 0 0ns 6 0 0 0ns 7 4496 4463 12279339ns 8 4500 4505 12278987ns 9 4500 4505 12278635ns 10 4500 4507 12193302ns 11 4500 4502 12278141ns 12 4500 4505 12277831ns 13 4500 4505 12192456ns 14 4500 4468 12277211ns 15 4500 4495 12276859ns 16 4500 4503 12191400ns 17 4500 4509 12191090ns 18 4500 4501 12275845ns 19 4500 4504 12275661ns 20 4500 4505 12190202ns 21 4500 4510 12274873ns 22 4500 4500 12052408ns 23 4500 4503 12137719ns 24 4500 4497 12188962ns 25 4500 4466 12273801ns 26 4500 4505 12051143ns 27 4500 4505 12188032ns 28 4500 4509 11913989ns 29 4500 4500 12272561ns 30 4500 4505 12272293ns Avg. Tx packets/second:4500 Avg. Rx packets/second:4500 Avg. Tx delay (milliseconds):12 [phuynh@scad ns-3.9]$ ./waf --run "examples/sg-sim/gw-bs-sim --nbSS=10 -duration=30 --statistic-start=10" Waf: Entering directory `/root/ns-allinone-3.9/ns-3.9/build' Waf: Leaving directory `/root/ns-allinone-3.9/ns-3.9/build' 'build' finished successfully (1.268s) 1 0 0 0ns 2 0 0 0ns 3 0 0 0ns 107 4 0 0 0ns 5 0 0 0ns 6 0 0 0ns 7 8991 8935 20416344ns 8 9000 9007 20415908ns 9 9000 9002 20415724ns 10 9000 9024 20415372ns 11 9000 9004 20415062ns 12 9000 8994 20414626ns 13 9000 8991 20414484ns 14 9000 8951 20414132ns 15 9000 9010 20413864ns 16 9000 9007 20413470ns 17 9000 9013 20413244ns 18 9000 9007 20412892ns 19 9000 9007 20412582ns 20 9000 9010 20412314ns 21 9000 9009 20412004ns 22 9000 8999 20411694ns 23 9000 8982 20411342ns 24 9000 8998 20411116ns 25 9000 8965 20410680ns 26 9000 9009 20410496ns 27 9000 9011 20410186ns 28 9000 9013 20409792ns 29 9000 9004 20409566ns 30 9000 9010 20409214ns Avg. Tx packets/second:9000 Avg. Rx packets/second:9000 Avg. Tx delay (milliseconds):20 108 B.4 The WAN Simulation Examples [phuynh@scad ns-3.9]$ ./waf --run "examples/sg-sim/bs-dc-sim --nbBS=3 --duration=10 --statistic-start=3 --data-rate=1.44Mbps" Waf: Entering directory `/root/ns-allinone-3.9/ns-3.9/build' Waf: Leaving directory `/root/ns-allinone-3.9/ns-3.9/build' 'build' finished successfully (1.261s) 1 0 0 0ns 2 27000 26943 2079999ns 3 27000 27000 2079999ns 4 27000 27000 2079999ns 5 27000 27000 2079999ns 6 27000 27000 2079999ns 7 27000 27000 2079999ns 8 27000 27000 2079999ns 9 27000 27000 2079999ns 10 27000 27000 2079999ns Avg. Tx packets/second:27000 Avg. Rx packets/second:27000 Avg. Tx delay (milliseconds):2 [phuynh@scad ns-3.9]$ ./waf --run "examples/sg-sim/bs-dc-sim --nbBS=5 --duration=10 --statistic-start=3 --data-rate=1.44Mbps" Waf: Entering directory `/root/ns-allinone-3.9/ns-3.9/build' Waf: Leaving directory `/root/ns-allinone-3.9/ns-3.9/build' 'build' finished successfully (1.266s) 1 0 0 0ns 2 45000 44905 2079999ns 3 45000 45000 2079999ns 4 45000 45000 2079999ns 5 45000 45000 2079999ns 6 45000 45000 2079999ns 7 45000 45000 2079999ns 8 45000 45000 2079999ns 9 45000 45000 2079999ns 10 45000 45000 2079999ns Avg. Tx packets/second:45000 Avg. Rx packets/second:45000 Avg. Tx delay (milliseconds):2 [phuynh@scad ns-3.9]$ ./waf --run "examples/sg-sim/bs-dc-sim --nbBS=10 -duration=10 --statistic-start=3 --data-rate=1.44Mbps" Waf: Entering directory `/root/ns-allinone-3.9/ns-3.9/build' Waf: Leaving directory `/root/ns-allinone-3.9/ns-3.9/build' 109 'build' finished successfully (1.265s) 1 0 0 0ns 2 90000 89810 2079999ns 3 90000 90000 2079999ns 4 90000 90000 2079999ns 5 90000 90000 2079999ns 6 90000 90000 2079999ns 7 90000 90000 2079999ns 8 90000 90000 2079999ns 9 90000 90000 2079999ns 10 90000 90000 2079999ns Avg. Tx packets/second:90000 Avg. Rx packets/second:90000 Avg. Tx delay (milliseconds):2 [phuynh@scad ns-3.9]$ ./waf --run "examples/sg-sim/bs-dc-sim --nbBS=15 -duration=10 --statistic-start=3 --data-rate=1.44Mbps" Waf: Entering directory `/root/ns-allinone-3.9/ns-3.9/build' Waf: Leaving directory `/root/ns-allinone-3.9/ns-3.9/build' 'build' finished successfully (1.264s) 1 0 0 0ns 2 135000 134715 2079999ns 3 135000 135000 2079999ns 4 135000 135000 2079999ns 5 135000 135000 2079999ns 6 135000 135000 2079999ns 7 135000 135000 2079999ns 8 135000 135000 2079999ns 9 135000 135000 2079999ns 10 135000 135000 2079999ns Avg. Tx packets/second:135000 Avg. Rx packets/second:135000 Avg. Tx delay (milliseconds):2 [phuynh@scad ns-3.9]$ ./waf --run "examples/sg-sim/bs-dc-sim --nbBS=20 -duration=10 --statistic-start=3 --data-rate=1.44Mbps" Waf: Entering directory `/root/ns-allinone-3.9/ns-3.9/build' Waf: Leaving directory `/root/ns-allinone-3.9/ns-3.9/build' 'build' finished successfully (1.271s) 1 0 0 0ns 2 180000 179620 2079999ns 3 180000 180000 2079999ns 4 180000 180000 2079999ns 5 180000 180000 2079999ns 110 6 180000 180000 2079999ns 7 180000 180000 2079999ns 8 180000 180000 2079999ns 9 180000 180000 2079999ns 10 180000 180000 2079999ns Avg. Tx packets/second:180000 Avg. Rx packets/second:180000 Avg. Tx delay (milliseconds):2