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Download EE194: Wireless Networks Group #2: Joseph Cerra and Stuart
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EE194: Wireless Networks Group #2: Joseph Cerra and Stuart Peloquin Dynamic Transmission Power Control in Wireless Ad-Hoc Networks INTRO • Discussed – Many forms of power conservation in wireless networks – Dynamic transmission power control as the preferred method for this research – JiST / SWANS as a simulation environment INTRO • Current work includes: – Learning the JiST API and SWANS network structure – Becoming familiar with the Java programming language (Stu) – Building a working front end to visualize simulation (Joe) – Implementing needed hooks and data structures INTRO • Future work includes: – Complete design specifications – Simulate various networks – Collect simulation results – Compare, contrast and report simulation results JiST / SWANS • Java in Simulation Time / Scalable Wireless Ad hoc Network Simulator – Well planned simulation environment – Very customizable – Follows OSI model – Open source: hooks can be added anywhere for statistic gathering JIST/SWANS • JiST API – JiST is comprised completely of Java code – Code written for JiST is also valid Java – Contains proxiable entities that are placeholders for different interface types • Transport Interface can be proxied by TCP or UDP etc… • This is done at simulation time by a bytecode rewriter JiST/SWANS • SWANS is a layer built on JiST – Implements many widely used protocols – All layers are customizable/rewriteable • Layers can also be dropped or added • Simulations can take place between the interface of any layers SWANS • Components – Physical – field, radio – Link – mac – Network – network address, network ip – Routing – Transport – Application – Common – message description Physical • Field defines the world parameters – Geometry: Area where nodes can be placed and move to – Placement: Where each node is placed – Mobility: Assign a mobility model to each node • Static, Random Waypoint, Teleport etc… – Fading, Path loss: Signal propagation loss • Radio Interface – Radio Noise Model • Field passes message to the radio • Radio Interface determines how to analyze received signal. Is it a message or noise or both. Link / Network • MAC Interface • How MAC protocol reacts to messages received by either Physical layer or Network Layer • Network Interface • • • • Determines node addressing Communicates to MAC layer Communicates with Routing Protocol IPv4 implementation Routing / Transport • Routing protocols currently implemented • Zone Routing Protocol • Dynamic Source Routing Protocol • Ad-hoc On-demand Distance Vector Routing Protocol – Receives calls from network layer to determine the next hop • Transport protocols • TCP – Uses TCP Sockets • UDP Application • Extremely useful application layer implementation – Can use any current java application • Java sockets are rewritten by the bytecode rewriter to use SWANS implementation of sockets – Each node can run any application including • Web server, database, peer to peer application • Random message generator • Node setup and statistics are handled by the driver Graphical User Interface • 8 Java Classes Created / Modified – 4 Created • MyCanvas, MyButton, MyNode, MyMenu – 4 Modified • Heartbeat, RadioInfo, Field, AppHeartbeat • Heartbeat – Field createSim(int nodes, field length) • mobility, fading, pathloss, radio, field – void createNode(i, field, placement, radioInfoShared, mapper, pl_in, pl_out) • radio noise, mac layer, network layer, application layer Created Classes Modified Classes •MyCanvas •Field –Pointer provided to heartbeat –Used exclusively for drawing nodes •MyNode –Stores Location, ID and Powerlevel •MyButton, MyMenu –moveRadio –API.Proxy() •RadioInfo –setPower(double) •AppHeartbeat –set/getPower –Computes neighbour statistics –Decodes messages for transmit power Shown Simulation • • • • • Wake up Broadcast yourself Listen to find all neighbors Compute # of neighbors for the last 5 awake cycles Base power on number of neighbors Current Work • • RSSI and Transmit strength not directly implemented in SWANS This functionality is added through extending the message, radio interface and MAC interface Current: Transmit strength • • • Transmit strength is added to the message payload from the MAC layer Radio Interface reads this and passes the message along at that signal strength MAC layer of next hop reads and strips this information before passing the message along Current: RSSI • Two implementations adopted for RSSI – Message passing – Scratch Pad • • Both are implemented in current devices Message Passing: (method of choice) – Radio adds signal strength information to each packet • Scratch Pad: – All layers have access to a pseudo layer that contains useful information – Includes a table of the signal strength of recent messages Current: RSSI - Models Node 1 Node 2 Application Application Transport RSSI RSSI information passed as part of the message Route Table MAC Radio Field Transport Route MAC mobility Radio mobility Future: RSSI / MAC • • Implement Message passing of RSSI strength Implement neighbour table in MAC layer – Include required power levels • ReqP = Tst – Rst + Pth • • • • ReqP: Required power Tst: Transmitted strength Rst: Received strength Pth: Threshold power level – If ReqPt < ReqPt-1 Then object is getting closer, use small Pth – If ReqPt > ReqPt-1 Then object is getting further away, use large Pth Future: Simulate - Static • Hook a complete network together using JiST/SWANS • Network will be composed of a collection of identical nodes – Each node has same transmit power – Simulations will be run on a variety of transmission powers • Determine a useful application to run at each node – Need it to announce itself and take advantage of multiple new nodes – Traffic pattern should be semi-uniform • Get power consumption statistics • CPU active/idle/sleep time • Radio sleep/idle/receive/send time at what power level Future: Simulate - Dynamic • Modify static network with new MAC layer – Uses RSSI and Transmitted strength levels to determine correct send parameters • Get similar power consumption statistics • Expect CPU time to be greater • Expect transmit strengths to be less Future: Routing • Determine modifications to use new information in MAC layer in the routing protocol • Goal is to use current routing protocol Link metrics for current routing protocol updated based on required transmit strength • Project Future • • • • • • GUI Standalone Set up interfaces: Which routing? Which transport? Which mobility? Conform to OSI model Include all simulation options in GUI rather than in runtime script Make GUI and Simulation more robust – Add functionality, more interfaces, and more networking components • Include network lifetime, CPU and Radio power consumption Questions?
