Centralized control of carrier sense threshold and channel bandwidth in high-density WLANs

Wireless LAN (WLAN) devices are now everywhere and their rapid spread has created dense deployment environments. Since WLAN transmission is based on carrier sense multiple access with collision avoidance (CSMA/CA), network capacity is degraded by the restrictions created by CSMA/CA on transmission opportunity in such high-density WLAN environments. The increased channel bandwidth available in recent WLANs also accelerates the degradation in transmission opportunity. This paper proposes a centralized control scheme of carrier sense threshold and channel bandwidth to improve spectrum efficiency in high-density WLAN environments. The proposed control determines the clear channel assessment (CCA) threshold and channel bandwidth by using the received signal strength indicator (RSSI) and wireless channel information of the access points (APs). A computer simulation shows that the proposed control raises the average throughput per station by 15 times compared to the conventional isolated APs.