Channel Access Balancing for Multiband Wireless LAN by Using Alternative Primary Channel

In the current IEEE 802.11 wireless LAN (WLAN), each station (STA) must obtain transmission opportunity (TXOP) on its primary channel. It means that current WLAN hardly utilizes the whole spectral resources in a frequency band if congestion occurs in some WLAN channels or bands. To overcome this problem, a concept of alternative primary channel (APCH) has been proposed. The APCH is a channel on which each STA can obtain TXOP if it is idle for a while, even when the primary channel is busy. This paper proposes a channel access procedure to realize load balancing of channel access among multiple WLAN channels by using APCH. Through computer simulation based on IEEE 802.11ac WLAN and the evaluation methodology of IEEE 802.11 WLAN, it is confirmed that the proposed channel access procedure can realize the load balancing. It is also confirmed that the performance of average area throughput and transmission delay can be improved by using APCH.