A congestion-aware multipath routing with cross layer design for wireless mesh networks

Many existing routing protocols for wireless mesh networks (WMNs) are based on minimal hop counts and cannot fit WMNs because they did not take into account congestions in networks. Although other multipath routing protocols use node- or link-disjoint routes, they are still based on minimal hop counts and may even cause extra congestion into networks. This is because a node-disjoint path may contain link-joined segments, which could be congested as many flows use them to forward packets. This paper proposes two congestion-aware routing metrics to enable routing protocols to consider congestion issues by exploring information available at the data link layer. One metric is called buffer occupancy ratio which considers the congestion status of nodes. The other metric is called successful frame sending rate which considers the congestion status of links. These two metrics are used to design a multipath routing protocol to find multiple less congested routes to improve network throughput. The simulation study has shown that the proposed routing scheme achieves significant throughput improvement with much more reliable packet delivery.