HFAQM: A hybrid fair active queue management mechanism to improve fairness and stability for wireless local area network

Active Queue Management (AQM) is a proactive scheme that controls network congestion by avoiding it before it happens. When implementing AQM in wireless networks, several contemporary issues must be considered, such as interference,
collisions, multipath-fading, propagation distance and shadowing effects, which affect the transmission rate of the links. These issues in WLAN networks with the existence
of different types of flow have a direct effect on fairness. The main idea behind the wireless network is using the flexibility of radio waves to transfer data from point to point that is giving WLAN the flexibility and mobility: wireless nodes can connect,
disconnect or even move from one access point to another rapidly. However, this affects the stability of the WLAN network. This research aims to reduce unfairness and instability by proposing a Hybrid-Fair AQM (HFAQM) scheme. HFAQM
comprises two mechanisms: Congestion Indicator Mechanism (CIM), and Control Function Mechanism (CFM). CIM was designed to improve fairness in WLANs by hybridizing queue delay with arrival rate as parameters to calculate the congestion level. Whereas, CFM was developed to improve network stability by using an adaptive control function with the ability to drop and mark packets to overcome the rapidly
changing characteristics of WLAN network. A series of experimental studies were conducted to validate the proposed mechanisms and four variants of AQM schemes, RED, REM, AVQ and CoDel, were chosen to evaluate the performance of HFAQM through simulation. The findings show that HFAQM’s main achievement is 99% fairness and improved stability by 10% from the closest scheme, with better throughput, queue length, queue loss, and outgoing link utilization as secondary
achievements. The proposed scheme provides significantly better fairness and stability in WLAN environment, with the existence of different types of flow.