SIRA: SNR-Aware Intra-Frame Rate Adaptation

An intra-frame rate control algorithm (Intra-RCA), called SNR-aware Intra-frame Rate Adaption (SIRA), is proposed to enhance the system performance of WiFi in fast time-varying environments. Widely used inter-frame rate control algorithms (Inter-RCA), which select the physical layer (PHY) rate of each frame based on the time averaged frame loss rate and the signal strength statistics, perform poorly for a long aggregate MAC protocol data unit (A-MPDU) due to the channel variation in mobile environments. Unlike the previous approaches, SIRA adapts the PHY rate on intra-frame basis, i.e., the PHY rate is updated in the middle of a frame according to user mobility. The performance of the proposed scheme is also evaluated by a trace-driven link level simulator employing the collected channel traces from real measurements. The simulation results show that SIRA outperforms the standalone Inter-RCA in all tested traces.