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Wireless Ad Hoc and Sensor Networks

Wireless Ad Hoc and Sensor Networks

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138 <strong>Wireless</strong> <strong>Ad</strong> <strong>Hoc</strong> <strong>and</strong> <strong>Sensor</strong> <strong>Networks</strong>TABLE 3.8Transmission TimeTrafficTQ (sec)New-RenoTCP (sec)Data1 31.58 30.05Data2 31.85 30.05VBR 30.07 30.05CBR1 30.04 31.95CBR2 30.05 30.04CBR3 30.04 30.043.6.5 Discussion of ResultsIn terms of PLR, transmission delay, <strong>and</strong> system power, TQ scheme outperformsthe New-Reno TCP scheme when congestion occurred, in allour test cases. TQ scheme has less PLR, less transmission delay, <strong>and</strong> highersystem power over New-Reno TCP. The specific performance improvementis shown in Table 3.9.3.7 Summary <strong>and</strong> ConclusionsThis chapter detailed a multilayer NN-based adaptive traffic-rate controllerfor ATM networks. The ATM switch/buffer dynamics along with thetraffic flow is modeled as a nonlinear dynamical system <strong>and</strong> an NNcontroller is designed to prevent congestion. This learning-basedapproach does not require accurate information about the network systemdynamics or traffic rate, it estimates the traffic rate at the switch <strong>and</strong> usesthis estimate to arrive at the controller. No initial offline learning phaseis required for the NN. By providing the NN with offline training usingthe backpropagation algorithm, the QoS improved slightly. However, inTABLE 3.9Performance Improvement for TQ over New-Reno TCPCase PLR (%)TransmissionDelay (%)SystemPower (%)Single source 11 2 2Multiple source 80 32 45Extended topology 100 1 0.4Fairness test 100 0.8 0.4

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