Multihop Wireless Networks: Opportunistic Routing

5.5 Performance Evaluation

In this section, we show the results of joint radio-channel assignment, routing, and scheduling for optimizing an end-to-end throughput solved by our methodology for two simple scenarios, and simulation results for more general networks. All the simulations are implemented in Matlab.

5.5.1 Two Scenarios with Different Link Qualities

We consider two four-node network scenarios in Figure 5.7 with different link qualities. Suppose each node has one radio that can be operated on two orthogonal channels. The PRR is indicated on each link. For simplicity, we assume the PRR is identical under different channels in each network. We assume each node is in the interference range of each other. So there is only one transmitter can be active on the same channel at any instant in the network. By applying the methodology in Sections 5.3 and 5.4, we solve the joint radio-channel assignment, routing, scheduling problem for maximizing the throughput from n1 to n4. We summarize the results for Figure 5.7(a) and Figure 5.7(b) in Table 5.3. The optimal throughputs from n1 to n4 for these two scenarios are 0.58 and 0.5, respectively. An interesting observation from Table 5.3 is that the opportunistic routing is not used when n1 is transmitting packets. Since in Figure 5.7(b), the channel conditions from the source to the relays are better than that from the relays to the destination, the maximum throughput is constrained by the bottleneck links from the relays to the destination. ...