【作者】 刘海涛；

【导师】 翁惠玉； 姬舒平；

【作者基本信息】 上海交通大学 ， 计算机技术（专业学位）， 2016， 硕士

【摘要】 伴随智能城市发展规划对WLAN无线网络发展要求的逐步深化,在WLAN热点小区更好的享受和体验更高的上网速度服务,是本文重点探究的实践方向。如何有效改善和提升单小区WLAN系统吞吐量整体性能及多用户独立性能提升,提高无线信道利用率,成为各运营商布网规划追求的目标,也对各厂商的WLAN产品的整体性能提升提出了更高的要求。排除干扰、带宽等相关制约因素对系统性能的影响,当前现网的WLAN用户间在进行同类型数据业务时仍存在信道抢占不均衡性的相关问题,在相同环境下用户体验参差不齐。在WLAN测试项目实践过程中,当多用户同时在线业务状态下,仍不能很好的满足用户的需求和体验。为了排查影响多用户系统性能的更深层次的原因,对802.11n协议中有关影响吞吐量的相关业务优先级的WMM参数进行了学习和研究。仿真研究了AP和STA WMM参数对多用户碰撞概率以及信道抢占比例的问题,确立了可能影响多用户吞吐量性能的AP和STA的WMM关键参数的关联关系,并通过在实验室环境下搭建和模拟WLAN多用户使用的典型场景,对AP和STA的WMM参数进行拆解匹配和分组遍历验证测试,最终确定了AP和STA维持相对低碰撞概率和信道相对均衡条件下的最佳WMM参数匹配的规律。与仿真分析进行对比,进而提出了基于周期性测量激活用户数(针对有业务需求的用户)的WMM参数随用户数动态变化的改进及优化方案。该方案主要体现在自适应动态调节特性和提前规避吞吐量损失的特性。在用户数量变化时,及时调整WMM参数,降低了碰撞概率,提前规避流量损失,而不是统计了损失再来调整挽救。方案在新的外场性能测试中得到了进一步的验证,为最终达到提升WLAN小区的整体吞吐量性能以及各共享STA的良好感知度奠定了基础。在整个实践过程中,新算法验证成功并发挥了积极作用,能够显著改善多用户同时业务时因碰撞导致的吞吐量损失问题,有一定的推广应用价值,并为持续WMM参数的逐步深化和改进工作奠定了良好的基础。更多还原

【Abstract】 With the development of intelligent city planning for the development of WLAN wireless network requirements,in the WLAN hotspot community to enjoy and experience better Internet service speed,is the focus of this paper to explore the direction of practice.How to effectively improve and enhance the overall performance of single cell system throughput and user independent performance in the Wlan network,in order to improve the utilization rate of wireless channel,network operators become the pursuit of the goal,and make the manufacturers put forward higher requirements on the overall performance of the WLAN product promotion.Eliminating such as interference inside and outside the systems and the bandwidth limitation to affect the system performance,the current network between WLAN users are still not balanced to use the channel preemption in the same environment,and the user’sdata-service experience is uneven.Meanwhile in the WLAN test project in the course of practice,the multi-users’ throughput performance test could not meet the user’s needs and experience,unable to compete with competitors in the same test environment.In order to quickly find the deeper reasons affecting the system performance,we intensived study and learned about the influence of throughput in 802.11 n protocol agreement about WMM parameters of different types of AC priority.Through simulation analysis and optimization of WMM parameters,the WMM parameters of AP and STA are disassembled and matched and the association assignment is used for traversal verification in groups in the laboratory tests.Eventually,we find the best matching rule of WMM parametersby matching rules of AP and STA each other to send and receive signals.Compared with the simulation analysis,we put forward the optimization scheme,which is to dynamically adjust the parameter of WMM by period measurement of the avtive user numbers online business status before throughput loss occurs.This scheme is mainly reflected in the characteristics of adaptive dynamic regulation and the avoidance of throughput loss.Changes in the number of users in a timely manner to adjust the WMM parameters to reduce the collision probability,to avoid the loss of traffic in advance,rather than the statistical adjustment of the loss to save.The proposed scheme is well verified in the new field performance test,and laid the cornerstone of the foundation in order to improve the overall throughput performance of WLAN cell and the good perception of shared STA.In the whole practice process,the new algorithm is proved to be successful and effective,it can significantly improve the throughput loss caused by collision between AP and STAs at the same time and has certain popularization and application value,and lays a good foundation for the continuous deepening and improvement of WMM parameters.更多还原