Wireless Ad Hoc and Sensor Networks

Optimized Energy and Delay-Based Routing 371p 3p 4p 2 35p 513 n p 1 n 2 2 546p 6s4 5 5n 3n 55 n 46p 7p 85FIGURE 8.6Least-cost spanning tree using the OEDR protocol.protocol for node p 8 . On the other hand, Figure 8.6 shows the least-costspanning tree for node p 8 using the OEDR protocol.To compare the route efficiency of the two protocols, observe the pathfrom the source p 8 to the destination p 3 for both the OLSR and OEDRprotocols. The path using the OLSR protocol is given by p 8 −> n 4 −>s −> n 2 −> p 3 and the cost of the path is: Cost p = ,8, p 6+ 6+ 6+ 4=223according to equation (8.2). On the contrary, the path using the OEDR protocolis p 8 −> n 5 −> s −> n 1 −> p 3 and the cost of the path is: Cost p =8,p 35 + 4 + 4 + 3=16,which is much smaller than the cost using the OLSRprotocol. This clearly shows that the proposed OEDR protocol results ina least cost or optimal cost path from the source to the destination.8.3.5 The OEDR Protocol SummaryThe basic functioning of the OEDR protocol is briefly described in thefollowing steps:1. Neighbor sensing: Each node in the network transmits HELLOpackets to its neighbors. When HELLO packets are received, eachnode updates the information of delay and energy of the linksfrom their neighbors in the neighbor table, along with the energylevel (available energy) of the neighbors.2. Multipoint relay selection: For each node in the network, its neighbortable is used to select the MPR nodes from the one-hop neighborsto reach all the two-hop neighbors with minimum costs,using the MPR selection algorithm given in Section 8.3.3. Topology information declaration: All the nodes in the network thatare selected as MPR nodes transmit TC messages, with energy-delay