RARRA Receiver Assisted Robust Rate Adaptation

Abstract

The IEEE 802.11 wireless local area network (WLAN) standard, especially 802.11a remains the most popular way to exchange data over wireless links. The major requirement is to adapt to highly dynamic channel conditions with minimum over- head and ensure robustness and speed of transmission. To this end we propose a novel Rate Adaption Scheme RARRA (Receiver Assisted Robust Rate Adapta- tion). Our key contributions include exploiting the more precise channel estima- tion of SNR-based Rate Adaptation coupled with estimating the channel condition at the receiver and nally sending this estimated information to the transmitter with minimum overhead. In other words we avoid RTS/CTS overhead to send the channel condition to the transmitter and use acknowledgment rates to serve` this purpose. Secondly, we di erentiate the cause of frame loss as either due to channel error or collision using RTS/CTS but in an adaptive fashion to minimize overhead but at the same time ensure that rate is not falsely changed due to frame loss caused by collision. RARRA exploits the best of SNR based approaches and provides channel condition at the receiver to the transmitter with minimum over- head thereby ensuring optimal rate switching decision aided by Adaptive RTS that provides robustness.