QoS control scheme that uses back pressure traffic control for wireless LANs

The spread of the Internet has given rise to strong demands for real-time services such as voice and streaming video. Since these services require guarantees that may include transmission rate, delay, and delay variance, the network, including the wireless access networks, must offer quality of service (QoS) guarantees. However, no radio access system fully supports QoS controls. In this paper, we propose a new QoS control scheme that uses back pressure traffic control and alters the Inter Frame Space (IFS) length of stations (STAs) according to the traffic circumstances of the wireless local area network (WLAN). It measures traffic of each user and controls the amount of data transmitted in order to guarantee the throughput of each user. This paper shows that the problem of “priority inversion” occurs and that the QoS is degraded when conventional schemes are employed in the medium access control (MAC) layer. The effectiveness of the proposed scheme is validated by comparison against conventional schemes. The results reveal that the proposed scheme can guarantee QoS in terms of throughput even if there is lot of best effort traffic and improve transmission delay performance.