Optimal Routing for Decode-Forward in Cooperative Wireless Networks

Abstract

We investigate routing in cooperative multiple-terminal wireless networks in which the nodes can collaborate with each other in data transmission. First, we motivate cooperation by showing that decode-forward, an information-theoretic cooperative coding strategy, achieves rates significantly higher than those achievable by the conventional multi-hop routing, a point-to-point non-cooperative coding strategy. We then construct an algorithm to find optimal (rate-maximizing) routes for decode-forward. We show that the algorithm is able to find shortest optimal routes and is optimal in fading channels. However, the algorithm runs in factorial time in the worst case. So, we propose a near-optimal heuristic algorithm that runs in polynomial time. The heuristic algorithm always outputs optimal routes when the nodes transmit independent codewords, and outputs optimal routes with high probability when the nodes transmit arbitrarily correlated codewords. Lastly, we implement decode-forward using low-density parity-check codes to compare the bit error rate performance of different routes.