AFEC - Adaptive Forward Error Correction for 802.11a Wireless LAN

Abstract

Degradation in channel condition due to fading and multipath effects can corrupt transmitted frames in wireless networks. To improve performance, one viable approach is to use forward error correction (FEC) schemes such as Reed-Solomon or similar codes. We analyze the performance of several Reed-Solomon codes applied to 802.11a wireless local area network (WLAN). The codes differ in their error correcting capability. Quantitative analysis shows that in an adverse environment, it is beneficial to use a more powerful error correcting code. But in a more benign environment, a reduced-strength code can be benefucial. Based on the results, an adaptive FEC (AFEC) is proposed. It adaptively selects error correcting scheme appropriate for the current environment. Through cross-layer information interchange, the method can be implemented easily and leads to better performance in WLAN. Issues related to the incorporation of the scheme into the 802.11a frame structure are also addressed.