To Handling Link Asymmetry for Wireless Mesh Access Networks Using a Cross-Layer Approach

In wireless mesh access networks working in an ad hoc model, link asymmetry exists because of the heterogeneous transmission range of mesh clients and mesh routers. In such networks, several challenges, including the unidirectional link problem, heterogeneous hidden problem, and heterogeneous exposed problem, can dramatically degrade network performance. In this paper, we develop a cross-layer approach for mesh access networks to simultaneously address these challenges and improve network performance. The main ideas of our approach are to eliminate the unidirectional link at the network layer and design novel handshake and channel reservation mechanisms at the medium access control (MAC) layer using topological information collected in the network layer and to eliminate the collision rate at the TCP layer. Via a combination of theoretical analysis and extensive evaluation, we can achieve the better performance with lower cost in comparison with existing approaches.