Routing Strategies in Broadband Multihop Cooperative Networks

Two fundamental properties of wireless networks, the variable link quality and the broadcast nature of the transmission, have often been ignored in the design of routing protocols. In this paper, we address the routing issue in broadband systems from a link-layer point of view. We focus on a clustered multihop wireless network. A link quality metric is first proposed to measure broadband links; then, three routing strategies, which were proposed in our previous study for flat fading scenarios, are re-designed to achieve cooperative and frequency diversity gain. The outage analysis and simulation results of the proposed three routing strategies show that all three protocols can achieve L(d_c + 1)-order diversity, where L is the number of relays in each relay cluster and d_c is the error correcting capability of the linear block code. The outage of optimal routing remains constant with an increase in the number of hops, M. While, the outage of ad-hoc routing increase linearly. N-hop routing, where a joint optimization is performed every N hops, can achieve a good complexity-performance tradeoff.