Selection metrics for cooperative multihop relaying

Cooperative relaying enables nodes to actively cooperate to deliver packets to their destination. The bestselect protocol (BSP) implements a type of cooperative relaying that generalizes single path routing with sets of nodes (relay-sets) replacing the concept of a single node relay. Thus, while in traditional single path routing, packets hop from node to node, in BSP, packets hop from relay-set to relay-set. Through the exchange of channel gain information between relay-sets, the best node within a relay-set is selected to transmit the data packet on behalf of the entire relay-set. The node selected depends on the metric used. Any metric that can be posed in a dynamic programming framework can be used. In this paper, performance gains from a number of selection metrics are investigated. Specific selection metrics include maximizing the minimum channel gain along the path, minimizing end-to-end delay, minimizing the total power, and minimizing the total energy. It will be shown that BSP can achieve significant gains in all of these metrics.