Power and Rate Optimisation for Multi-Hop Networks and DF with Incremental Redundancy

Within this paper we address the energy minimisation problem for a multi-hop relay networks where incremental redundancy (or mutual-information accumulation) is used as relaying strategy. The problem is to find optimal power levels and transmit rates, or equivalently optimal power and time slot lengths. First, we explain how the structure can be exploited to solve the problem with numerical optimisation methods. However, this approach is inefficient for larger networks as the number of optimisation parameter increases faster that the number of nodes in the network. Based on the results obtained by the numerical methods, we propose a very efficient resource allocation algorithm whose complexity increases only linearly with the number of nodes. Furthermore, the scheme can be implemented in a distributed way, since only partial channel state information is required for resource allocation at each node.