Rate Adaptation Technique for Coexisting Heterogeneous IEEE 802.11 Wireless LANs

摘要

Different physical (PHY) layers of IEEE 802.11 provide the option of multiple data rates [such as 802.11 (a/b/g) all provide multi-rate capabilities]. A good rate adaptation mechanism is required to determine the optimal transmission rate appropriate for the current wireless channel condition. But a rate adaptation mechanism is still unspecified in the 802.11 standards. In this paper, we design a rata adaptation scheme for coexisting heterogeneous IEEE 802.11 WLANs which comprise three different modules. Firstly, based on the distance from the AP, a node chooses the achievable set of rates applicable to it. Secondly, we differentiate a packet loss by measuring the probability that a packet is lost due to channel error. Finally, our rate adaptation mechanism selects the best rate based on the measured normalized rate efficiency. We have performed extensive simulations and the result shows that the proposed mechanism outperforms other well-known existing rate adaptation schemes by achieving higher network throughput.