Optimum Selective Decoding Schemes in MAC Protocol for MIMO Ad-Hoc Networks

IEEE 802.11 MAC designs encounter two problems: (1) interferences from neighboring nodes or from hidden nodes and (2) collision from simultaneous transmissions within the same contention floors. This paper presents the optimum selective decoding schemes in MAC protocol (OSDS-MAC) for MIMO Ad-hoc network. It is able to mitigate interferences by using a developed minimum mean-squared error (MMSE) technique. This interference mitigation combined to ML decoding schemes for the Alamouti coding achieves to receive and differentiate the data streams from other co-channel users. As a result, it allows a pair of simultaneous transmissions to the same or different receivers which increase the network utilization. Moreover, the presented three decoding schemes are optimally selected corresponding to the three structures determined by the number of RTSs and the type of CTS packets. Both theoretical channel capacity and simulation results show that the proposed OSDS-MAC system outperforms the MIMA-MAC system for the cases of (1) single data stream and (2) two independent data streams which are simultaneously transmitted from the two transmitters.