Performance evaluation of congestion aware transmission opportunity scheduling scheme for 802.11 wireless LANs

Abstract

In the last two decades, Wireless Local Area Networks (WLANs) based on 802.11 have become crucial in offering Internet services with high data transmission rates. Under crowded scenarios like airports, shopping centers, and stadiums, WLANs can be easily congested due to their random access nature and limited operational capability. This may result in a reduced user multimedia experience. With a proper Transmission Opportunity (TXOP) allocation and scheduling scheme, the user service quality could be improved under such scenarios. In this paper, a Congestion-Aware Transmission Opportunity (CA-TXOP) scheme is proposed, allocating transmission resources by considering network level congestion and information like buffer status, channel quality, and data rates. The CA-TXOP scheme prioritizes congested and noncongested user stations and improves the overall network performance. Simulation results show that the CA-TXOP scheme attained 45%, 35%, and 20% enhancement compared with Fixed, Bi-level, and FRA-TXOP scheduling schemes. Such scheme applies to future congested scenarios like smart buildings and organizations that require satisfying video quality to all the user stations.

Keywords

• 802.11
• WLAN
• Internet
• TXOP
• CA-TXOP
• Congestion