Research And Implementation On Optimizing WLAN Packet Transportation

The802.11n standard supports data rates up to300Mbps (theoretically600Mbps atthe maximum), but the actual throughput is no more than200Mbps. In this paper, twoimportant factors that affect the WLAN throughput, efficiency of the medium accesscontrol layer and packet rate control, have been analyzed, and corresponding measuresare put forward for improvement.First, this paper analyzes the essential reason of the lower efficiency of the MAClayer, illustrates the impact of frame aggregation mechanism on network performance,as well as issue that may arise in the case of high channel bit error rate. Dynamic frameaggregation algorithm based on the link information is proposed to solve this problem.The algorithm assesses the quality of the channel, based on the link information, anddynamically adjusts the key parameters during aggregation, and can increase thethroughput of the network, especially when the channel is really bad.Secondly, the rate control mechanism on the WLAN has been studied, includingtypical rate control algorithms. And MRRA rate control algorithm is designed for802.11n network, considering the deficiency of those typical ones when picking the bestrate. MRRA uses Mutil-Rate Retry mechanism, takes various factors in the actualnetwork into account and performs better than other algorithms.Finally, this paper completes the design and implementation of the wireless drivermodule in the wireless access point (AP) software system, and successfully applys thenew frame aggregation algorithm and MRRA rate control algorithm to the system. TheAP is tested by professional tester, including the proposed aggregation algorithm andMRRA rate control algorithm, to verify the correctness of the theoretical work.This paper is under the background of the school education wireless networkproject. The research has been applied to the project and effectively improves theperformance of the network.