Enhanced Coordinated Spatial Reuse: Bidirectional Multiple AP Coordination for IEEE 802.11be

The popularity of WiFi keeps increasing because of its capability to deliver a cost-efficient broadband Internet connection. However, a new problem emerges when many basic service sets (BSSs) are deployed in the same area, which increases inter-access point (AP) contention and co-channel interference. Inter-AP contention will decrease the overall throughput in the area and cause long application delay. The rise of bandwidth-hungry and low-latency applications like virtual and augmented reality, online gaming, and video streaming makes it urgent to solve this problem. The IEEE 802.11be Working Group (TGbe) proposes a new feature, coordinated spatial reuse (CSR). This feature allows concurrent transmissions of multiple APs through coordination between APs, reducing inter-AP contention and co-channel interference. However, existing proposed CSR algorithms use one-way coordination where the AP that initiates the CSR transmits at its maximum power and other APs optimize their transmit (TX) power accordingly, resulting in poor throughput for other APs. To solve this problem, we propose a new bidirectional CSR algorithm, Enhanced Coordinated Spatial Reuse (ECSR), which collaboratively determines the TX power for all APs by setting an appropriate interference tolerance limit. To the best of our knowledge, this is the first work that proposes bidirectional multiple AP coordination for CSR. We evaluate our proposed algorithm in dense enterprise scenarios. Simulation results show that our proposed design achieves three times higher throughput than the traditional carrier sense multiple access (CSMA) technique and four times more than the existing one-way CSR. Our experimental results also show that none of the stations participating in ECSR transmissions have low throughput.