IEEE 802.11 downlink traffic shaping scheme for multi-user service enhancement

In IEEE 802.11 wireless LAN (WLAN), due to the combination of a first-in-first-out (FIFO) transmission queue and the retransmission policy in the serving access point (AP), a single station that is moving away from the AP, e.g., thus handing off to a neighbouring AP, can have a significant negative impact on the services other users receive in the same basic service set (BSS). In this paper, we present a traffic shaping algorithm to control this undesirable effect. Experimental results show that our algorithm manages to maintain stable throughput levels in networking applications that otherwise would have experienced high throughput degradation. This algorithm constitutes an innovative implementation of a traffic shaper that can be easily adopted by the current state-of-the-art IEEE 802.11 AP products to enhance the performance of WLANs, since the algorithm can be implemented in the device driver and no specific modification of hardware is needed.