【作者】 刘博；

【导师】 冯春燕；

【作者基本信息】 北京邮电大学 ， 通信与信息系统， 2008， 硕士

【摘要】 BWM(宽带无线多媒体,Broadband Wireless Multimedia)网络结合移动电视网络和宽带无线接入网络的特征构建联合网络,旨在寻求运行高效、成本低廉的技术途径,从空中接口、无线接入网络、核心网络、业务平台和终端等不同侧面全方位地达成“三网融合”。BWM系统的MAC(媒体接入控制,Medium Access Control)层在管理分配上层资源及提高通信传输效率中起着至关重要的作用。在BWM系统MAC层中,采用多播广播这种点到多点的信息传输方式,比点对点通信节省了频带资源以及发射功率,是未来通信发展的主要趋势。本文通过对国内外现有研究中BWM系统MAC层多播广播基本原理及关键技术的研究和分析,分别在BWM系统MAC层多播机制、多播数据调度、广播机制中设计了全新的关键技术解决方案。在多播机制中设计了新型的多播连接动态分配算法,选举产生多播基站群,使群内所有基站在同一频道上使用相同的连接标识,并且一个连接同时动态承载多个频道,以减少连接数量;在多播数据调度中,提出了创新的公平性调度算法及时间频率综合调度算法,分别达到无限逼近绝对公平性和减小冷门节目和热门节目等待时间的差异的目的;在广播机制中,设计了新型的按需广播计时及计数算法,采用多个定时器轮询及计数器轮询的方式,寻找广播基站的空闲时隙为数据通信服务,并对其性能进行了理论分析;并且针对以上算法在Windows系统下采用opnet仿真软件及matlab平台进行了仿真实验,对实验数据进行分析后,发现多播连接动态分配算法可以在一定程度上节省连接资源,两个多播数据调度算法均可达到目标,按需广播计时及计数算法可以提高资源的利用率。更多还原

【Abstract】 BWM Networks constructs the networks based on the characters of Mobile Video Networks and the Broadband Wireless Access Networks, in order to find the technical way of operating efficiently and costing lowly, realizing the "combination of three networks" from all the directions and sides which contains air interface, wireless access networks, core networks, service flat and terminals. The MAC layer of BWM system plays an important role in managing and allocating up-layer resources and enhancing the transmitting efficiency. In MAC layer of the BWM networks, using multicast and broadcast which belongs to the transmitting mode of point to multipoints can save more frequency band resources and more transmitting power than the point to point communication, and is the main trend of future communication development. Based upon the research and analyze of the basic theory and key technology of multicast and broadcast in the MAC layer of BWM in the existing domestic and abroad research, this paper designed innovative resolving schemes of key technology in the multicast scheme, multicast data scheduling and broadcast scheme of the MAC layer of BWM. In the multicast scheme, we design the novel Algorithm of Dynamic Allocation of the Multicast Connection, voting to generate the multicast base-station group, making all the base-stations use the same connection identity on the same channel and one connection undertake several channels at one time dynamically, looking forward to reduce the number of the connections; In the multicast data scheduling, we propose the created Optimized Equity scheduling algorithm and scheduling algorithm of Frequency and time First, aiming separately to approach the absolute equity infinitely and to reduce the difference between cold and hot programs in the waiting time. In the broadcast scheme, we design the novel Timing and Counting algorithm in the broadcast on demand, alternate checking several timers and counters to find the idle slots of the broadcast to provide service for communication of data, enhancing the utilizing efficiency of the resources. We carried out the simulation on the opnet and matlab in windows for these algorithms, after analyzing the result of the experiment, we found that algorithm of Dynamic Allocation of the Multicast Connection can save the resources of connections on a certain degree, both of the two multicast data scheduling algorithms can reach its goal, and the Timing and Counting algorithm in the broadcast on demand can enhance the utilizing efficiency of the resources.更多还原