Using space and network diversity combining to solve masked node collision in wireless adhoc network

In wireless ad hoc network, the traditional carrier sensing multiple access/collision avoidance (CSMA/CA) protocol cannot solve the masked node problem, which affect the network performance greatly. Our proposed collision separation technique overcomes the shortcoming of the IEEE 802.11 request-to-send-clear-to-send (RTS-CTS) handshake by combining the space diversity provided by the antenna array and network diversity provided by the media access control (MAC) layer. In this work, the colliding packets caused by masked nodes are not discarded but stored and combined with the selected retransmission packets to separate the data from different nodes. The steady states of the nodes in the network are analyzed via a Markov chain model. The network goodput and delay performance are also investigated. Compared to network assisted diversity multiple access (NDMA), our proposed method, i.e., space and network diversity combination, SNDC for short, can provide higher throughput and lower delay performance.