Wireless Ad Hoc and Sensor Networks

Optimized Energy and Delay-Based Routing 3791210Average contention timesOEDROLSRAODVContention time (milli-seconds)8642020 30 40 50 60 70Mobility (km/hr)80 90 100FIGURE 8.12Contention time and mobility.The average packet delay is illustrated in Figure 8.13, which indicatesthat the E2E delays using the OEDR protocol are always smaller than thedelays incurred using the OLSR and AODV protocols, owing to the factthat delay information is taken into account in OEDR when calculatingthe routes. Moreover, the average packet delays tend to increase with anincrease in the number of nodes because of higher interferences andchannel contentions resulting from the density of the nodes and theirtraffic.According to Figure 8.14 the throughput/delay values of the OEDRprotocol are higher than those of OLSR and AODV protocols, because ofsignificant reduction in the average delays achieved by the OEDR protocol.As the density of the nodes and the traffic increases, the throughput/delay ratio decreases as shown in the figure, because of an increase indelays caused by the retransmissions.Energy delay product as a cost function and contention times are shownin Figure 8.15 and Figure 8.16, respectively. The contention times for theOEDR protocol are almost equal to those of the OLSR protocol and thedifferences are negligible (in milliseconds). This indicates that the OEDRprotocol does not result in additional increase in the contention times.The energy and delay product values are smaller for the OEDR protocol