Quality of Service Enhancement in Wireless LAN: A Systematic Literature Review

In early, IEEE introduced 802.11 standards for Wireless Local Area Networks (WLANs). Due to the rapid increase in the human demand of wireless networks worldwide. It required efficiency for the current generation, IEEE introduced the 802.11e standard for quality of service in 2005. This standard based on the EDCA mechanism for different priority traffic to provide QoS in WLANs. Nowadays EDCA is still one of the most important techniques of channel access for providing quality of service in the latest standards of IEEE for WLANs (802.11a, 802.11ax). EDCA based on four different traffic priorities (Voice, Video, Best effort, Background). The main contribution of this research is to systematically review researches on QoS enhancement of wireless LAN. This study Identifying, categorizing, and synthesizing the appropriate researches based on Kitchenham's systematic review methodology. This review identifies the methods which are used for improving the QoS of WLAN. We also focused on the issues as contention window adjustment and channel sensing which causes a lot of collision in EDCA. There are also fairness issues between low and high priority traffic which cause starvation. Preliminary results have been reported by answering 2 selected research Questions. 30 studies were selected out of the initial set of 55 research articles. Studies answering selected research questions have been included in this report.