Multi-BSS Multi-User Full Duplex MAC Protocol based on AP Cooperation for the Next Generation WLAN

With the dense deployment of basic service set (BSS) in the next generation Wireless Local Access Network (WLAN). The overlapping coverage of multiple BSSs leads to intensified contention conflicts, low efficiency of buffer state reports (BSR) collection and a sharp decline in system throughput. To solve this problem, this paper proposes an access point (AP) cooperation based multi-BSS multi-user full duplex multiple access protocol (CMMFD). Firstly, access control (AC) divides the STAs in the cooperative network area into overlapping STA and non-overlapping STA. A bi-level channel resource allocation algorithm is designed. The first level is channel resource allocation in the collection stage of BSR and inter-node interference information (BI), and the second level is channel resource allocation in full duplex data transmission. Secondly, a protocol framework for parallel BI information collection of cooperative APs is designed. AC schedules cooperative APs to send trigger frame at the same time, and triggers STAs in each BSS to report BI information on the assigned channel resource with p-probability access mode. Finally, AP forwards the collected BI information to AC, and AC assigns the STAs in the multi-BSS to perform multi-user full-duplex transmission on the resource unit (RU). Theoretical analysis gives the closed form expressions of the mean number of STAs successfully collected by AC in the cooperation area and saturated network throughput. Simulation results show that compared with MU-FuPlex and EnFD-OMAX protocol, CMMFD protocol improves the network throughput by 29.6% and 31.2% respectively.