An Aggregation Aware Multi-Path Forwarding Paradigm for Wireless Mesh Networks

In multi-radio wireless mesh networks, a network device simultaneously transmits packets over different channels by using multiple radios. Such frequency diversity not only in creases throughput but makes multi-path routing approaches extremely interesting. This is because the channel diversity reduces the risk for intra- and inter-flow interference. A fundamental problem to solve is the forwarding strategy which determines which packets to be sent over what multi-path segments at any given time. Ideally, the forwarding strategy should schedule flows according to the capacity constraints imposed by the channel assignment. However, the possibility to improve MAC layer efficiency by aggregating small packets into larger ones is reduced when packets are forwarded to different next-hops. In this paper, we develop a novel packet forwarding strategy for multi-radio mesh networks that combines the benefits of multi-path routing with packet aggregation. In our cross-layer approach, we effectively trade-off aggregation opportunities with channel diversity. Simulation results show that our approach can improve network throughput and delay by up to 15 percent and 25 percent, respectively, compared with aggregation unaware forwarding strategies.