Collision-Aware Design of Rate Adaptation for Multi-Rate 802.11 WLANs

One of the key challenges in designing a rate adaptation scheme for IEEE 802.11 Wireless LANs (WLANs) is to differentiate bit errors from link-layer collisions. Many recent rate adaptation schemes adopt the RTS/CTS mechanism to prevent collision losses from triggering unnecessary rate decrease. However, the RTS/CTS handshake incurs significant overhead and is rarely activated in today's infrastructure WLANs. This paper proposes a new rate adaptation scheme that mitigates the collision effect on the operation of rate adaptation. In contrast to previous approaches adopting fixed rate increasing and decreasing thresholds, the scheme varies threshold values based on the measured network status.