Design and Evaluation of a Cross-Layer Framework for Improving 802.11 Networks

This paper reports on the design and evaluation of a class of cross-layer design (CLD) framework for improving the performance of 802.11-based wireless local area networks (WLANs). While various CLD approaches have been proposed for improving the performance of WLANs in recent years, the problem of efficient channel utilization, higher throughput, lower packet delay, and fairness has not been fully solved yet. To overcome the performance problems of 802.11, we propose a CLD framework which is based on a cross-layer medium access control (MAC) protocol called the channel-aware buffer unit multiple access (C-BUMA). In the framework, the radio propagation (i.e. physical layer) is combined with the MAC sub-layer to develop a robust cross-layer communication. By sharing channel information with the MAC protocol, the approach reduced unnecessary packet transmissions, and hence reduced bandwidth wastage and significantly improved the system performance. The proposed CLD method is evaluated by extensive simulation experiments. A comparison with 802.11 standards is provided. Results obtained show that the network achieves up to 13.5% higher throughput, 56% lower packet delay, 40% better fairness, and 38% lower packet dropping with the proposed CLD. We also found that the proposed CLD outperforms Pham’s CLD with respect to network throughput and packet dropping. The analysis and empirical results reported in this paper provide some insights into the design and evaluation of a CLD framework for improving data rate of 802.11 networks which may help researchers in this field to overcome the remaining design issues and challenges.