Wireless Ad Hoc and Sensor Networks

Optimized Energy and Delay-Based Routing 391CH A4856CH B56CH A4856CH B5CH C7ABC1237(d)465 BS98FIGURE 8.20 (d)(d) In this case, CH B sends its information about node 5 and node 6 to CH C. CH C checksif it is in range with these nodes. Because CH C is not in range with both the nodes, it createsits own optimal path to the BS. Now CH B chooses the best relay node between node 5 andnode 6 based on the link_cost_factor. Here, node 6 is chosen as the optimal relay node forCH A and B. Therefore, two separate optimal routes using the link_cost_factor are createdfrom the CHs, if no common relay node is identified.node. By doing this step, only nodes that are closer to the BS arefiltered out as candidate RNs, thereby avoiding longer routes.3. A list containing candidate RNs is sent to the next CH (or relaynode). The CH, in turn, checks whether it is in range with any ofthe nodes in the list or not. The CH sends a HELLO packet toeach of the nodes in the list, and if it receives a response packetfrom any of the nodes, then those nodes are considered to be inrange with the CH.CH1HELLOHELLOCH1RESPONSERESPONSECH1CH1CH2CH2HELLOCH2CH2RELAYINVITECH1 sends HELLOpackets to all nodesin rangePotential relay nodes andback RESPONSE packetsCH with list of potential nodes ID, energy available, delay and distance to BSNode that receive HELLO message from CHCH1 sends HELLOpacket with updatedinformation to CH2CH2 checks if itis in range withpotential relay nodesFIGURE 8.21Steps to route information to the BS.