Joint Power and Bandwidth Allocation in Multihop Wireless Networks

This paper considers power and bandwidth allocation to maximize the end-to-end rate in a multihop wireless network. Assuming an orthogonal frequency division multiplexing (OFDM) system, we formulate an optimization problem for joint power and subcarrier allocation in a network with one destination and multiple sources and relays. We then focus on low-complexity algorithms for the special case of a multihop network with only one source. In particular, we develop an algorithm for a two-hop network based upon the observation that the optimal frequency allocation in a two-hop network has a two-band structure under certain conditions. For a network with more than two hops, we propose a greedy approach to subcarrier allocation. Simulation results suggest that the performance of the proposed algorithms closely follow the optimum performance. Moreover, our results suggest that more hops do not always improve the end-to-end spectral efficiency for frequency-selective fading channels.