Space and network diversity combination for masked node collision resolution in wireless ad hoc network

In wireless ad hoc networks, the traditional Carrier Sensing Multiple Access/Collision Avoidance protocol cannot solve the masked node problem, which affects the network performance greatly. Our proposed collision separation technique overcomes the shortcoming of the IEEE 802.11 Request-To-Send-Clear-to- Send handshake by combining the space diversity provided by the antenna array and network diversity provided by the Medium Access Control 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 throughput and delay performance are also investigated. Compared to network assisted diversity multiple access, our proposed method can provide significantly higher throughput and lower delay.