Optimizing the Use of Relays for Link Establishment in Wireless Networks

Multihop packet relaying has been shown to extend the achievable communication space in sparsely connected ad hoc networks, in sensor networks, and over long distance links. This paper investigates the properties of relay-enabled networks as a function of the number of relays and whether packets are sent one at a time or whether multiple packets are simultaneously sent along the relay chain. When packets are sent one at a time, an optimal number of relays is found that maximizes the throughput and minimizes delay. The optimal number is in terms of a standard hop, which enables the number of relays,maximum throughput, and minimum delay to be determined for any communication within the environment. When multiple packets are sent at a time, a maximum throughput is found that is independent of distance and noise. The performance depends on the separation in hops between simultaneous transmissions in the relay chain. The optimal separation is found in the limit of many relays to be 5 hops across many different radio environments. These results allow us to define feasible delay-throughput-distance performance regions and provide inputs to better multi-hop wireless network design.