Wireless Ad Hoc and Sensor Networks

190 Wireless Ad Hoc and Sensor NetworksThe system is simulated using the method of Bambos et al. (2000),optimal DPC, SSCD (Jagannathan et al. 2002), and constrained secondorderpower control (CSOPC) (Jantti and Kim 2000). Outage probabilityand total power are taken as metrics to evaluate the performance of theschemes. Plots of outage probability and total power consumed are generatedfor a given number of users in the network. A plot of outageprobability with number of users is also generated to show the performanceof the scheme when number of users in the cellular network varies.Figure 5.2 shows the randomly placed location of users in the cellularnetwork, which is divided into seven hexagonal cells. Figure 5.3 showsthe plot of outage probability with time. From this simulation, it is clearthat the outage probability in the system using SSCD or optimal DPCscheme is lower when compared to CSOPC and Bambos scheme, i.e., ourapproach can accommodate a greater number of users, rendering highsystem capacity. Figure 5.4 illustrates the plot of total power consumedby all the users in the network with respect to time. The result shows thatSSCD and optimal DPC allow the users to attain their target SIRs withlower transmitter powers when compared to other schemes, while maintaininga lower outage probability. Simulation experiments are performed64Base StationMobile Station2km0−2−4−6−5 −4 −3 −2 −1 0 1 2 3 4km5FIGURE 5.2Cellular network with seven cells.