A joint approach to routing metrics and application-aware rate adaptation in multi-radio wireless mesh networks

摘要

In this paper, we address a joint problem of routing and application-aware rate adaptation for multi-radio Wireless Mesh Networks (WMNs). WMNs are emerging as wireless backhaul technology to connect wired and wireless networks to the internet in a cost-effective way. These networks use multi-radio capabilities of mesh routers to achieve high performance. However supporting the quality of service (QoS) of real-time multimedia applications is still an important research issue as there is need for the cross-layer optimization strategies involving application, routing, MAC and physical layers. Towards this, we analytically derive our routing metric by using 802.11 Distributed Coordination Function (DCF) basis access mechanism. Using this model, we design a novel cross-layer routing metric called Interference and Contention Aware (ICA) metric by considering delay, channel utilization, inter-flow interference and intra-flow interference to find the optimal path. We extend the work by adapting the traffic rate at the application layer of a source node by using the statistics provided by the routing metric. We implement this joint approach using Optimized Link State Routing (OLSR) in NS2. The results reveal that ICA routing metric performs better in terms of throughput and delay compared to Metric for Channel Diversity (MIND), Contention-Aware Transmission Time (CATT) and Interference Aware Routing (iAWARE). Further, cross-layer approach of routing and rate adaptation helps the applications to adapt the transmission rate based on the congestion at the network layer.