Figure 2From: Performance analysis of distributed cluster-based MAC protocol for multiuser MIMO wireless networksCB-CSMA/CA access mechanism in an infrastructure network with a multiple-antenna AP as the receiver. In (a) an example of a successful transmission is shown, where STA1 and STA2 in have a shorter backoff than that of STAs in and they transmit first. In (b) both clusters begin to transmit at the same time and hence collision occurs.Back to article page