基于负载均衡的无线AP设计与实现

发布时间：2018-01-28 07:02

本文关键词： 负载均衡流量控制接入控制 LTE　出处：《湖北工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着智能交通系统的快速发展,在公交车上实现Internet访问的需求越来越大。公交车可以利用开放式的可用访问点(Access Point,简称AP)通过WLAN技术访问Internet。同时,高峰期公交车上乘客数量较多,当AP负载较重,且网络资源无法合理分配时,易导致网络效率低下,甚至瘫痪。因此,建设高性能的公交车载网络以满足乘客的多样化业务需求是发展的必然趋势。本课题以联发科公司生产的MT7620A芯片为主CPU,以Linux为操作系统,开发了一款基于负载均衡的高性能AP,该设备将应用于公交系统,并致力于解决公交密集乘客访问冲突问题,为乘客提供高质量的网络服务。主要研究内容如下:1)根据设备的功能和要求,决定采用同时支持802.11ac与802.11n标准的同步双频硬件方案;完成了相关芯片选型及主要硬件模块的设计与实现,最后对设备在5G频段的性能进行了测试,测试结果表明在5G频段中上下行吞吐量均值都90Mbps左右,传输时延上均值约在40MS左右。2)对IEEE802.11标准MAC层协议进行了分析,并对影响无线网络吞吐率的因素作了重点研究,得出无线网络的吞吐率与退避窗口、退避次数成正比,与站点数量成反比的结论。在此基础之上,总结了公交车载网络的互联网访问场景需求下MAC层存在的不足,从而提出基于流量控制和负载接入控制的AP主控式负载均衡策略。3)设计了系统软件框架,详细分析了负载信息的衡量指标、采集以及更新策略,并在此基础之上实现了流量控制模块、接入控制模块和相应的Web管理界面。其中流量控制模块进一步细分为流量统计、流量识别与分类、流量调度这三个模块进行实现。完成基于PPP的LTE功能模块。
[Abstract]:With the rapid development of intelligent transportation system, there is a growing demand for Internet access on buses. Buses can make use of open access points to access Point. At the same time, the number of passengers on the bus during the rush hour is more, when the AP load is heavy, and the network resources can not be allocated reasonably. It is easy to lead to inefficiency and even paralysis of the network. It is an inevitable trend to build a high-performance bus-borne network to meet the diverse business needs of passengers. This topic is based on the MT7620A chip produced by MediaTek Co., Ltd. (CPU). Using Linux as operating system, a high performance APP based on load balancing is developed, which will be applied to public transportation system and solve the problem of bus dense passenger access conflict. Provide high quality network service for passengers. The main research contents are as follows: 1) according to the function and requirement of the equipment. Decides to adopt the synchronous dual-frequency hardware scheme which supports both 802.11ac and 802.11n standards; The related chip selection and the design and implementation of the main hardware modules are completed. Finally, the performance of the equipment in the 5G band is tested. The test results show that the average throughput of uplink and downlink is about 90Mbps in 5G band. The average value of transmission delay is about 40ms. 2) the IEEE802.11 standard MAC layer protocol is analyzed, and the factors that affect the throughput of wireless network are studied. The paper draws the conclusion that the throughput rate of wireless network is proportional to the Backoff window, the times of Backoff is proportional to the number of sites, and the number of sites is inversely proportional. This paper summarizes the shortcomings of the MAC layer under the requirement of the Internet access scenario of the bus-borne network. Thus, the system software framework is designed based on flow control and load access control. The measurement index, collection and update strategy of load information are analyzed in detail. On this basis, the flow control module, access control module and the corresponding Web management interface are implemented. The flow control module is further subdivided into flow statistics, traffic identification and classification. The three modules of traffic scheduling are implemented, and the LTE function module based on PPP is completed.
【学位授予单位】：湖北工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN925.93;U463.67

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