Achieving Optimal Throughput in Cooperative Wireless Multihop Networks With Rate Adaptation and Continuous Power Control

This work is an offline study to characterize the performance of cooperative relaying in interference-limited multihop networks, where nodes are equipped with multi-rate and continuous power control capabilities. We formulate a cross-layer flow-based framework to obtain the achievable throughput rates by jointly optimizing the parameters for multi-path routing, scheduling, rates, transmit powers, and selection of cooperative nodes. This framework is generic in that it is not restricted to any particular cooperative combining technique or type of network architecture. To take continuous power control into account, we introduce a non-trivial power allocation subproblem while keeping the main cross-layer framework as a linear program. We solve the problem optimally to obtain the max-min throughput for the case when cooperation is based on the distributed Alamouti code and networks have a mesh-like topology. We derive a number of practical engineering insights based on our numerical optimal results obtained for small-to-medium-sized random networks. In particular, we establish that the use of cooperative relaying in a small-to-medium-sized random mesh network often does not yield significant performance gains in throughput and connectivity even when multi-rate and continuous power control capabilities are available at the nodes.