Multihop Wireless Networks: Opportunistic Routing

4.4 Performance Evaluation

In this section, we use Matlab to investigate the impact of different factors on the end-to-end throughput bound of opportunistic routing, such as source–destination distances, node densities, and number of forwarding candidates. Both line and square topologies are studied for each factor. We also compare the performance of single rate opportunistic routing and multirate ones, and the performance of OR with traditional routing (TR). We call a routing scheme “traditional” when there is only one forwarding candidate selected for each packet relay at each hop.

The OR schemes we investigate include single-rate ExOR (Biswas and Morris 2005), single/multirate GOR and single/multirate LMTOR introduced in Section 4.3.1. For ExOR (Biswas and Morris 2005), each transmitter selects the neighbors with lower ETF (Expected number of Transmissions over Forward links) to the destination than itself as the forwarding candidates, and neighbors with lower ETF have higher relay priorities. For GOR, the forwarding candidates of a transmitter are those neighbors that are closer to the destination, and candidates with larger advancement to the destination have higher relay priorities. The EAR metric proposed in Section 4.2 is used to select the transmission rate for each node in the multirate scenario. For multirate LMTOR, the algorithm and metric proposed in Section 4.3.1 is used to choose transmission rate and forwarding candidates at each node. All the evaluations are under ...