摘要： 在IEEE 802.11n协议中引入帧聚合机制能够提高无线局域网MAC层的效率，但会增加速率自适应算法对信道变化的反应时间，降低网络吞吐量。针对该问题，提出一种改进的速率自适应算法JodaRA。引入权重思想统计聚合帧的发送情况，设计基于子帧丢失加权和的速率选择方案。采取混合型速率选择策略，利用发送端的RSSI与接收端的传感器信息进行链路状态感知，根据链路状态选取合适的速率选择方案并动态设定聚合帧的最大长度，以提高算法的实时性与准确性。仿真结果表明，在不同的节点移动状态下，与RRAA、MinstrelHT和SampleLite 3种算法相比，JodaRA算法的平均UDP吞吐量分别提高90%、57%和22%。

关键词: IEEE 802.11n协议, 无线局域网, 链路状态, 速率自适应算法, 网络吞吐量

Abstract: The introduction of frame aggregation mechanism in the IEEE 802.11n protocol improves the efficiency of the MAC layer in Wireless Local Area Network(WLAN).However,the response time of the rate adaptation algorithm to the channel changes increases and the throughput of the network reduces accordingly.To solve this problem,we propose an improved rate adaptation algorithm JodaRA.We first introduce the weight idea to calculate the transmission of aggregated frame,and design a rate selection scheme based on the weight sum of lost subframes.Then,by adopting the hybrid rate selection strategy,JodaRA utilize the RSSI at the sender and sensor information at the receiver to sense the link state.Finally,according to the link state,JodaRA select the suitable rate selection scheme and dynamically set the maximum length of the aggregated frame to improve its accuracy and real-time performance.Simulation results show that compared with those of RRAA,MinstrelHT and SampleLite algorithms,the average UDP throughput of JodaRA algorithm increases by 90%,57% and 22% respectively in different node mobility states.

Key words: IEEE 802.11n protocol, Wireless Local Area Network(WLAN), link state, rate adaptation algorithm, network throughput

中图分类号: 

• TP391