A Novel Distributed Pseudo-TDMA Channel Access Protocol for Multi-Transmit-Receive Wireless Mesh Networks
A key approach to improve the capacity of Wireless Mesh Networks (WMNs) is to equip routers with multiple transmissions or receptions (MTR) capability. Thus, the resulting MTR WMN has significantly higher network capacity because routers can activate multiple links simultaneously. This, however, requires a MTR link scheduler that maximizes network capacity or equivalently, one that is capable of deriving a short schedule. Henceforth, we propose Period Controlled Pseudo Time Division Multiple Access (PCP-TDMA), a link scheduler that allows nodes to cooperatively reduce an initial link schedule or superframe over time in a distributed manner. Routers are able to adapt the superframe size iteratively using only local information to accommodate any topological changes. This means PCP-TDMA is particularly suited for use in large-scale MTR WMNs. We have evaluated PCP-TDMA in various network topologies, and compared it against ALGO-2, a centralized algorithm that uses global topological information to derive a schedule and thus serves as a benchmark. We also compare PCP-TDMA against two distributed approaches: JazzyMAC and ROMA. The results show that PCP-TDMA achieves similar performance with the centralized algorithm in all scenarios, and outperforms the distributed approaches significantly. Specifically, in a fully connected network, the resulting superframe length of PCP-TDMA is less than 1/3 and 1/2 of JazzyMAC and ROMA, respectively.