Wireless Ad Hoc and Sensor Networks

250 Wireless Ad Hoc and Sensor Networks6.6 Simulation ParametersThe AODV routing protocol with 2-Mbps radio channel rate was used.The random topology is used to evaluate the schemes. The maximumpower used for the 802.11 and proposed DPC is equal to 0.2818 W. Theproposed DPC should maintain a target SIR of 10, which is 2.5 timeshigher than the minimum SIR for error-free reception that is equal to 4(~6 db), as in Singh and Raghavendra (1998). The target SIR is increasedto overcome a possible change in channel condition between the timewhen the power was calculated and the time when this power is used.For the proposed DPC, the design parameters are selected as Kv = 0.01,and = 0.01. The power safety factor in the case of retransmissions is setto 1.5 for the proposed DPC scheme.The random topology consists of a 1000 × 1000 m square area with 100nodes placed at random. Node mobility is also randomly generated witha maximum speed of 3 m/sec and with 2-sec pauses between the moves.The simulations are executed for 50 sec. CBR traffic is used for 50 flows,starting randomly during the first 2 sec. Each data flow generates steadytraffic using 512-B-long packets. The results were averaged over simulationtrials using different fading effects, node placement, and movement.The simulations were executed by varying the per flow rates. The radiochannel with 2-Mbps bandwidth was used.In the random topology scenario, each flow can use different numberof hops (miniflows) between the source and the destination pairs. Thiscan lead to different end-to-end throughput depending on number ofhops used in a particular scenario (determined by node placement).Hence, the miniflow transmissions were used instead of end-to-endtransmissions.The total data transmitted for all miniflows is presented in Figure 6.6.Compared to the 802.11, the proposed DPC transmits more data regardlessof traffic flow rate, because the higher utilization is achieved for theproposed protocol, as explained in Section 6.3. Similarly, the proposedprotocol outperforms the 802.11 protocols in terms of energy efficiency,as shown in Figure 6.7, indicating lower energy consumption than 802.11.Regardless of the traffic load, the proposed protocol allows transmissionof more data per joule when compared to 802.11. Higher energy efficiencyof the proposed protocol is a result of transmission power control scheme,which selects a more suitable power value needed for correct decodingof the frames. Additionally, the proposed protocol consumes energy moreefficiently in case of congestion, because it performs better in terms ofthroughput when compared to the 802.11.