Wireless Ad Hoc and Sensor Networks

128 Wireless Ad Hoc and Sensor Networksretransmission. In comparison, New-Reno TCP takes about 210 msecover its open-loop case. This is about 3.5 times longer than the proposedTQ scheme.The corresponding results for TCP New-Reno are shown in Figure 3.23ato Figure 3.23d. The congestion window in New Reno-TCP scheme isshown in Figure 3.23a, which exhibits a sawtooth-like behavior. We alsotested with some other single traffic sources and the results are similar tothose shown in earlier text. The compared results between TQ and New-Reno TCP are shown in the Table 3.4.Example 3.6.2: Multiple SourcesHere S1 to S3 were MPEG data obtained from a Web site (MPEG tracefiles). These data sets are from the movies “Star Wars IV,” “Jurassic ParkI,” and sport event “Soccer” (Figure 3.24). The CBR sources S4 to S6 haddata rates of 2, 1, and 0.5 Mbps, respectively. Source rates are adjustedusing the feedback uk ( ) for each source. The bottleneck buffer size is taken807060cwnd (packets)504030201000 10 20 30 40Time:(s)50 60 70 80(a) Congestion window.FIGURE 3.23Performance in TCP scheme with single source: (a) congestion window, (b) cumulativepacket loss, (c) buffer utilization, and (d) PLR.