Wireless Ad Hoc and Sensor Networks

6.8.6 Power Selection for the Rate ..................................................2666.8.7 Backoff Mechanism ..................................................................2676.8.8 MAC Protocol Design..............................................................2686.9 Dynamic-Programming-Based Rate Adaptation .............................2686.9.1 Buffer Occupancy State Equation ..........................................2696.9.2 Cost Function ............................................................................2706.9.2.1 Queue Occupancy Cost.............................................2706.9.2.2 Transmission Cost ......................................................2706.9.2.3 Approximating Cost Function .................................2716.9.3 The Riccatti Equation...............................................................2726.9.4 Additional Conditions for Modulation Selection ...............2746.9.5 Implementation Consideration...............................................2756.10 Simulation Results ................................................................................2756.10.1 One-Hop Topology...................................................................2766.10.2 Two-Hop Topology...................................................................2766.10.3 Random Topology with 50 Nodes.........................................2796.10.4 Two-Hop Results ......................................................................2796.11 Hardware Implementation of DPC....................................................2826.11.1 Hardware Architecture ............................................................2846.11.1.1 Wireless Networking Test Platform ........................2846.11.1.2 Generation-4 Smart Sensor Node............................2856.11.1.3 ADF7020 ISM Band Transceiver..............................2866.11.1.4 Limitations...................................................................2866.11.1.5 RF Setup.......................................................................2876.11.2 Software Architecture...............................................................2876.11.2.1 Frame Format............................................................2876.11.2.2 Baseband Controller.................................................2886.11.2.3 Operation Modes......................................................2886.11.2.4 RSSI Reading .............................................................2886.11.2.5 DAPC MAC controller ............................................2896.11.3 Experimental Results ...............................................................2906.11.4 Slowly Varying Interference ...................................................2916.11.5 Abruptly Changing Channel with Slow Update ................2936.11.6 Abruptly Changing Channel with Fast Update..................2936.12 Conclusions ............................................................................................296References..........................................................................................298Problems ..........................................................................................................2997 Distributed Fair Scheduling in WirelessAd Hoc and Sensor Networks ...............................................3037.1 Fair Scheduling and Quality of Service ............................................3037.2 Weighted Fairness Criterion................................................................305