Wireless mesh network performance: MIMO two-way relay vs. CSMA/CA based protocols

Infrastructure wireless mesh network has been attracted much of attention due to a wide range of its application such as public wireless access, sensor network, etc. The application of well-known CSMA/CA based MAC protocols to mesh network, however, reveals high latency and low resource utilization due to problems of hidden terminal, exposed terminal, information asymmetry etc. Several alternative protocols including directional MAC, multichannel MAC only provide marginal improvement. In recent publication, a cross-layer design employing multiple antenna techniques called MIMO two-way relay is proposed for one dimensional mesh network. Owing to interference cancellation and bidirectional stream multiplexing ability of MIMO in combination with an efficient channel access scheme of TDMA/TDD, MIMO two-way relay provides significantly high end-to-end capacity. In this paper, we propose MIMO two-way relay as an alternative PHY/MAC protocol of CSMA/CA. A network simulator employing MIMO two-way relay is developed and more details on packet relaying mechanism of the algorithm are presented. Simulation results show that MIMO two-way relay achieves an extremely large improvement in network throughput, and packet delay reduction in comparison with CSMA/CA mesh networks.