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Mobile and Ad hoc Networks Background of Ad hoc Wireless Networks Wireless Communication Technology and Research Ad hoc Routing and Mobile IP and Mobility Wireless Sensor and Mesh Networks Student Presentations Introductory Lecture http://web.uettaxila.edu.pk/CMS/SP2012/teAWNms/ Objectives Where is Wireless Communication today? Where has it come from in the last decade? What is its future potential? Introduction to Mobile Ad hoc, Sensor and Mesh networks What are key research areas in wireless communication? How do the features in Ad hoc wireless networks different from traditional wireless systems (WiFi: 802.11a/b/g/n, 3G, mobile WIMAX: 802.16e)? Mobility issues Security and other issues Research topics Text Books AD HOC NETWORKS Technologies And Protocols by Prasant Mohapatra and Srikanth Krishnamurthy The handbook of AD HOC WIRELESS NETWORKS by Mohammad Ilyas Text Books Ad Hoc Mobile Wireless Networks Protocols and Systems by C.K. Toh Mobile Ad hoc Networking by Stefano Basagni, Marco Conti, Silvia Giordano and Ivan Stojmenovic Overview of the Course Introduction Foundations of Wireless Communications - Wireless Channel Foundations of Wireless Communications – Modulation Review of Networking Wireless Physical and MAC layer Wireless Area Networks (WPAN, WLAN, WWAN) and MAC Layer Wireless MAC protocols Wireless Routing Wireless TCP Mobile IP Quality of service Wireless Sensor Networks Mobile Ad hoc Networks Vehicular Ad hoc Networks Mesh Networks Wireless Network Security Standardization Research Papers Physical and MAC layer Routing in Wireless Opportunistic routing and network coding Network Layer and Routing Routing Metrics Geographic Routing Routing and Scalability Routing Algorithms Algorithmic foundations for scalability Energy issues Sensor Networks Wireless Routing Security Trust and Reputation systems Incentives, mechanisms, etc. Physical and link level issues Presentations Objectives of course Learn about challenges in wireless networking What forces us to reconsider many traditional designs? Understand state-of-the-art in wireless/ubiquitous systems Get a broad view of the ongoing research in the wireless domain Have a good understanding of their capabilities and limitations 6 Course Materials Course Web page http://web.uettaxila.edu.pk/CMS/SP2012/teAWNms Visit regularly Announcements Lecture Notes and Assignments Research papers Pdf/ps version of the papers will be on the Web page ~30 papers, Combination of classic and recent work. 7 Reading Papers Is this a vision/position/direction paper, or just a measurement/implementation? How the paper is compared to others? Can I mentally categorize this paper somewhere in the taxonomy? “Differs from X as follows; has the following in common with Y” What is the most important contribution? 8 Reading Papers (2) Does this advance the state of the art? Did you learn anything new? Does it provide evidence which supports/contradicts hypotheses? Is there experimental validation? Any technical flaws? Will the paper generate discussion in the class? How readable is the paper? Is the paper relevant to a broader community? 9 Covered Topics (will try!) Overview The challenges, technologies, and trends Wireless Fundamentals Source and channel coding Frequency spectrums Wireless LAN MAC protocols Wireless Internet – Mobile IP 10 Covered Topics (2) Routing for Wireless Ad Hoc Routing TCP in wireless enviroment Power Management wireless Sensor Networks Quality of Services (QoS) Hybrid Wireless Networks – Architectures– Pricing, Power Control, Load Balancing Special Topics 11 Why wireless networks? Mobility: to support mobile applications Costs: reductions in infrastructure and operating costs: no cabling or cable replacement Special situations: No cabling is possible or it is very expensive. Reduce downtime: Moisture or hazards may cut connections. 12 Why wireless networks? (cont.) Rapidly growing market attests to public need for mobility and uninterrupted access Consumers are used to the flexibility and will demand instantaneous, uninterrupted, fast access regardless of the application. Consumers and businesses are willing to pay for it 13 The Two Hottest Trends in Telecommunications Networks Millions 700 600 500 400 Mobile Telephone Users Internet Users 300 200 100 0 1993 1994 1995 1996 1997 1998 1999 2000 2001 Years Source: Ericsson Radio Systems, Inc. Growth of Home wireless 16 Wireless is THE Key Driver for the Future Internet Historic shift from PC’s to mobile computing and embedded devices… >2B cell phones vs. 500M Internet-connected PC’s in 2005 >400M cell phones with Internet capability, rising rapidly Sensor deployment just starting, but some estimates ~5-10B units by 2015 ~750M servers/PC’s, >1B laptops, PDA’s, cell phones, sensors ~500M server/PC’s, ~100M laptops/PDA’s Wireless Edge Network INTERNET INTERNET Wireless Edge Network 2005 2010 17 Market Size Wireless as the common case vs. the exception Laptop (54%) vs. desktop sales (46%) >2B cell phones vs. 500M Internetconnected PCs Estimates of ~5-10B wireless sensors by 2015 Staggering Market Statistics • 9 million hotspot users in 2003 (30 million in 2004) • Approx 4.5 million WiFi access points sold in 3Q04 • Sales have tripled by 2009 • Many more non-802.11 devices Rapid deployment of new technology Highly dynamic environment Must accommodate new/unexpected technologies 18 Why is it so popular? Flexible Low cost Easy to deploy Support mobility 19 Applications ? Ubiquitous, Pervasive computing or nomadic access. Ad hoc networking: Where it is difficult or impossible to set infrastructure. LAN extensions: Robots or industrial equipment communicate each others. Sensor network where elements are two many and they can not be wired!. Sensor Networks: for monitoring, controlling, e 20 Infostations Mobile hosts traveling through fixed network Good for periodic download or upload of bulky data Wireless islands (interconnected by wired network) Gas stations Here and there on the freeway Possibly an invisible infrastructure with mobile-aware applications In reality, you may need to know to go to it Original paper assumes this: information kiosks Coverage is spotty Cost is lower than complete coverage 21 Ad hoc networks Collection of wireless mobile nodes dynamically forming a temporary network without the use of any existing network infrastructure or centralized administration. Hop-by-hop routing due to limited range of each node Nodes may enter and leave the network Usage scenarios: Military Disaster Relief Temporary groups of participants (conferences) 22 Sensor networks Deployment of small, usually wireless sensor nodes. Collect data, stream to central site Maybe have actuators Hugely resource constrained Internet protocols have implicit assumptions about node capabilities Power cost to transmit each bit is very high relative to node battery lifetime Loss / etc., like other wireless Ad-hoc: Deployment is often somewhat random 23 Ad hoc networks, continued Very mobile – whole network may travel Applications vary according to purpose of network No pre-existing infrastructure. Do-it-yourself infrastructure Coverage may be very uneven 24 Networked Embedded Computers Connected to network send and/or receive May be embedded only for network access networked appliances Network sensors historical sites & other locations 25 Embedded Peer Composite devices (HW+SW) security system Distributed composites vs. hardwired devices Network client-defined composites reuse of constituents ease of change extendibility & scalability 26 Networked Embedded Computers Issues Late binding Network Naming Discovery IPC User-interface deployment Multi-appliance control Access control Existing social protocols not supported by existing mechanisms All co-located users can use appliance Restriction to contents per user 27 Location-Aware Computing Motivation location-based action nearby local printer, doctor nearby remote phone directions/maps location-based information real virtual person’s location history/sales/events walkthrough story of city augmented touring machine 28 Pose-Aware Computing Operations based on locations and orientations of users and devices Motivation Augmented reality 29 Wearable Pose-Aware Computers Computers on body track body relative movements monitor person train person 30 Beyond Desktops/Servers Embedded Mobile Location Interactive Sensor Flight Simulator Wearable Active badge 32 Summary Need to be connected from everywhere and anytime. Need to be connected on movement Need to good quality service on those situation. Interworking with the existing networks 33 Classification of Wireless Networks Mobility: fixed wireless or mobile Analog or digital Ad hoc (decentralized) or centralized (fixed base stations) Services: voice (isochronous) or data (asynchronous) Ownership: public or private 34 Classification of Wireless Networks Area: wide (WAN), metropolitan (MAN), local (LAN), or personal (PAN) area networks Switched (circuit- or packet-switched) or broadcast Low bit-rate (voice grade) or high bit-rate (video, multimedia) Terrestrial or satellite 35 What is special on wireless? Channel characteristics Half-Duplex Location dependency Very noisy channel, fading effects, etc., Resource limitation Bandwidth Frequency Battery, power. Wireless problems are usually optimization problems. 36 What is special on wireless? Mobility in the network elements Very diverse applications/devices. Connectivity and coverage (internetworking) is a problem. Maintaining quality of service over very unreliable links Security (privacy, authentication,...) is very serious here. Broadcast media. Cost efficiency 37 Big issues! Integration with existing data networks sounds very difficult. It is not always possible to apply wired networks design methods/principles here. 38 Internet Design Goals 1. Connect existing networks initially ARPANET and ARPA packet radio network 2. Survivability - ensure communication service even in the presence of 3. 4. 5. 6. 7. network and router failures Support multiple types of services Must accommodate a variety of networks Allow distributed management Allow host attachment with a low level of effort Allow resource accountability 39 Problems Host mobility is not considered in the design. There is a hierarchal design. How Ad hoc wireless networks can be handled A layered design. Layer should be independent of each other. It is not work at all in wireless TCP Battery shortages; Etc,. 40 Disconnection / store & forward Many Internet protocols assume frequent connectivity What if your node is only on the Internet for 5 minutes every 6 hours? How do you browse the web? Receive SMTP-based email? 41 High availbility requirements No QoS assumed from below Reasonable but non-zero loss rates What’s minimum recovery time? 1 RTT But conservative assumptions end-to-end TCP RTO Interconnect independent networks Federation makes things harder: My network is good. Is yours? Is the one in the middle working? Scale Routing convergence times, etc. 42 Trends Multimedia over IP networks Next Generation Internet with features for “soft” QoS RSVP, Class-based Queuing, Link Scheduling Voice over IP networks Packet Voice and Video RTP and ALF Intelligence shifts to the network edges Better, more agile software-based voice and video codecs Programmable intelligence inside the network Proxy servers intermixed with switching infrastructure Java code: “write once, run anywhere” Implications for cellular network infrastructure of the 21st century? 43 Issues Scalability Must scale to support hundreds of thousands of simultaneous users in a region. Functionality Computer-phone integration Real-time, multipoint/multicast, location-aware services, security Home networking, “active” spaces, sensors/actuators 44 Issues(2) Leverage evolving IP traffic models Provisioning the network for the extrapolated traffic and services Proactive Infrastructure Computing resources spread among switching infrastructure Computationally intensive services: e.g., voice-to-text Service and server discovery 45 Wireless Differences 1 Physical layer: signals travel in open space Subject to interference From other sources and self (multipath) Creates interference for other wireless devices Noisy lots of losses Channel conditions can be very dynamic 46 Wireless Differences 2 Need to share airwaves rather than wire Don’t know what hosts are involved Hosts may not be using same link technology Interaction of multiple transmitters at receiver Collisions, capture, interference Use of spectrum: limited resource. Cannot “create” more capacity easily More pressure to use spectrum efficiently 47 Wireless Differences 3 Mobility Must update routing protocols to handle frequent changes Requires hand off as mobile host moves in/out range Changes in the channel conditions. Coarse time scale: distance/interference/obstacles change Fine time scale: Doppler effect Other characteristics of wireless Slow 48 Growing Application Diversity Collision Avoidance: Car Networks Mesh Networks Wired Internet Access Point Sensor Relay Node Ad-Hoc/Sensor Networks Wireless Home Multimedia 49 Challenge: Diversity Wireless Edge Network INTERNET INTERNET Wireless Edge Network 2005 2010 New architectures must accommodate rapidly evolving technology Must accommodate different optimization goals Power, coverage, capacity, price 50 Spectrum Scarcity Interference and unpredictable behavior Need better management/diagnosis tools Lack of isolation between deployments Cross-domain and cross-technology Why is my 802.11 not working? 51 Other Challenges Performance: Nothing is really working well Security: It is a broadcast medium Cross layer interception TCP performance 52 Assignment #1 Introduce Yourself: Name: Adeel Akram Department: Telecom Engineering Department Email Address: [email protected] Cell/Contact Number: 0323-5030712/051-9047566 Define terms highlighted in Yellow colour Q&A ?