Performance Enhancement of Wireless Local Area Networks

As wireless local area networks (WLANs) provide mobility and convenience to users, the efficiency of today´s WLANs are still far from satisfactory. Communications may be cut off when mobile stations travel between cells. Wireless data connections have high bit error rates, low bandwidth and long delays. Therefore, it is very important to improve their loss performance. In this paper, our main contribution is to analyze and evaluate several methods to improve the throughput performance of WLANs. We describe OPNET implementations for fine-tuning the physical layer and IEEE 802.11 layer related parameters. Through simulation we demonstrate that WLAN performance can be improved by tuning parameters such as slot time, short-inter-frame spacing, minimum contention window (CW_min), fragmentation threshold and request to send (RTS) thresholds. Customizing these parameters oppose to using the values specified in the standards will reduce collisions and delays, and increase throughput and channel utilization under various load conditions