【摘要】：無線網(wǎng)格網(wǎng)(Wireless Mesh Networks,WMN)是由一組帶有無線收發(fā)設(shè)備的通信節(jié)點組成,擁有動態(tài)自配置、自組織和自修復(fù)功能的分布式網(wǎng)狀網(wǎng)絡(luò)。應(yīng)急通信網(wǎng)絡(luò)作為WMN的一種典型應(yīng)用,在面對重大事故或災(zāi)難后的緊急救援中發(fā)揮著至關(guān)重要的作用。然而,現(xiàn)有關(guān)于WMN MAC協(xié)議研究及實現(xiàn)主要集中在基于IEEE 802.11s的競爭接入?yún)f(xié)議,該方案存在著資源利用率低、時延大、跳數(shù)小等諸多問題。為解決上述問題,本文研究了基于調(diào)度的信道接入機(jī)制,設(shè)計與實現(xiàn)了集中式和分布式兩種基于分配的WMN MAC協(xié)議。首先,針對跳數(shù)較少的小規(guī)模WMN設(shè)計了集中式的MAC協(xié)議。為提高信道資源的利用效率,本協(xié)議中采用了緊湊的時隙結(jié)構(gòu)和時隙分配方案。網(wǎng)絡(luò)中處于主控地位的基站節(jié)點根據(jù)本節(jié)點及所有其它從節(jié)點的業(yè)務(wù)需求,以一個OFDM符號塊為單位動態(tài)的分配全網(wǎng)各節(jié)點的傳輸時間。文章詳細(xì)描述了所設(shè)計的集中式WMN MAC協(xié)議的幀結(jié)構(gòu)以及節(jié)點入網(wǎng)、節(jié)點離網(wǎng)、時鐘同步、帶寬請求分配和差錯控制等協(xié)議運行過程,并在硬件平臺上實現(xiàn)驗證了所設(shè)計協(xié)議的有效性。由于集中式MAC在WMN跳數(shù)增多時存在較大的控制時延,本論文針對大規(guī)模WMN設(shè)計了一種分布式的MAC協(xié)議。相對于集中式WMN MAC協(xié)議而言,分布式WMN MAC協(xié)議中所有節(jié)點的地位對等,不存在一個主控的基站節(jié)點來管理全網(wǎng)的時隙分配。針對該網(wǎng)絡(luò)拓?fù)浣Y(jié)構(gòu),本文提出了一種分布式時隙分配算法,各節(jié)點根據(jù)兩跳鄰節(jié)點關(guān)系動態(tài)地分配時隙。該算法不受網(wǎng)絡(luò)規(guī)模限制且能更快的適應(yīng)網(wǎng)絡(luò)拓?fù)浣Y(jié)構(gòu)的變化。最后,論文在OPNET仿真平臺上從網(wǎng)絡(luò)模型、節(jié)點模型和進(jìn)程模型三個層次模擬了所設(shè)計的分布式WMN MAC協(xié)議。仿真結(jié)果表明所提算法比IEEE 802.11s、固定分配的時隙分配兩種算法擁有更高的吞吐量以及更小的時延。
[Abstract]:Wireless Grid Network (Wireless Mesh Networks,WMN) is a distributed mesh network which is composed of a set of communication nodes with wireless transceiver devices and has the functions of dynamic self-configuration self-organization and self-repair. As a typical application of WMN, emergency communication network plays an important role in emergency rescue after major accidents or disasters. However, the current research and implementation of WMN MAC protocol mainly focus on the competitive access protocol based on IEEE 802.11s, which has many problems, such as low resource utilization, large delay, small hops and so on. In order to solve the above problems, this paper studies the channel access mechanism based on scheduling, and designs and implements two distribution-based WMN MAC protocols, centralized and distributed. Firstly, a centralized MAC protocol is designed for small scale WMN with fewer hops. In order to improve the efficiency of channel resource utilization, a compact slot structure and slot allocation scheme are adopted in this protocol. In the network, the base station nodes in the main control position dynamically allocate the transmission time of each node in the whole network according to the service requirements of the node and all other slave nodes, and take a OFDM symbol block as the unit. This paper describes in detail the frame structure of the centralized WMN MAC protocol and the running process of the protocols, such as node access, node off-network, clock synchronization, bandwidth request allocation and error control. The validity of the designed protocol is verified on the hardware platform. Due to the large control delay of centralized MAC when the number of WMN hops increases, this paper designs a distributed MAC protocol for large-scale WMN. Compared with centralized WMN MAC protocol, all nodes in distributed WMN MAC protocol have equal status, and there is no one master base station node to manage the time slot allocation of the whole network. For the topology of the network, a distributed slot allocation algorithm is proposed, in which each node dynamically allocates time slots according to the two-hop neighbor node relationship. The algorithm is not limited by the network size and can adapt to the network topology changes more quickly. Finally, the distributed WMN MAC protocol is simulated on the OPNET platform from three levels: network model, node model and process model. Simulation results show that the proposed algorithm has higher throughput and lower delay than IEEE 802.11s.
【學(xué)位授予單位】：國防科學(xué)技術(shù)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TN915.04

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1 范雯琦;無線Mesh應(yīng)急通信網(wǎng)絡(luò)的TDMA MAC協(xié)議研究[D];國防科學(xué)技術(shù)大學(xué);2014年

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本文編號：2203427