Wireless Ad Hoc and Sensor Networks

Optimized Energy and Delay-Based Routing 409111098Delay vs network sizeoedsroedrDelay (s)765432140 50 60 70 80 90Number of nodes100 110FIGURE 8.42Average end-to-end delay with network size.on just the available energy and the delay. It can be noticed that whenthere are 70 nodes in the network, the energy consumed using OEDR andOEDSR protocols increases because of the nature of the topology. However,the increase in energy using OEDSR is less compared to OEDRbecause a different and more efficient route was selected.The average E2E delay is also lower for OEDSR when compared toOEDR as observed in Figure 8.42. This is because there are fewer nodesthat are selected as RNs in the OEDSR protocol, and this decreases processingand queuing time. In the case of OEDR, it is assumed that everynode knows the route to the BS, based on the MPR sets. Because of this,a longer route was selected to route information as OEDR is not an ondemandrouting protocol. The E2E delay includes the wake-up time fora node apart from the transmission time. Therefore, with more RNs, wakeuptime goes up, increasing the E2E delay.It can be observed from Figure 8.43 that the number of collisions in thenetwork is lower for the OEDSR when compared with the OEDR. OEDRuses more RNs to transmit data from the CHs to the BS. Moreover, whenselecting the multipoint-relay (MPR) nodes, the nodes send information totheir one-hop and two-hop neighbors, and this increases the number ofsignals being sent in the network. Because of this, the traffic in the networkgoes up, thereby increasing the number of collisions in the network.