本文關(guān)鍵詞：車載自組織網(wǎng)絡(luò)信息分發(fā)機(jī)制的研究　出處：《電子科技大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： VANET 基于地理位置的路由 多信道 MAC

【摘要】：隨著車輛數(shù)目的不斷增加,街道日益擁擠,行車安全不能得到有效保證,環(huán)境和能源供不應(yīng)求等問(wèn)題亟需解決。這些尖銳的問(wèn)題給國(guó)家?guī)?lái)不少經(jīng)濟(jì)損失。VANET的概念在不斷嘗試和探索的過(guò)程中誕生。它針對(duì)的是以車輛為節(jié)點(diǎn)的通信網(wǎng)絡(luò),與傳統(tǒng)的Ad Hoc網(wǎng)絡(luò)有很多不一樣的特征。VANET中車輛運(yùn)動(dòng)速度較快,網(wǎng)絡(luò)連接關(guān)系因時(shí)因地實(shí)時(shí)變化,節(jié)點(diǎn)密度分布不一,而且無(wú)線通信很容易受到高樓大廈等障礙物的阻擋。傳統(tǒng)的路由和MAC協(xié)議不再適用于VANET,而它們直接影響報(bào)文投遞率、時(shí)延、網(wǎng)絡(luò)吞吐量等通信指標(biāo)。因此,對(duì)路由和多信道MAC協(xié)議深入的研究勢(shì)在必行。本論文在第二章中概述了VANET路由當(dāng)前的研究進(jìn)展,分析了不同類型路由的優(yōu)缺點(diǎn)。本文提出GPCR-D的路由,與傳統(tǒng)的基于位置的路由不同的是:它考慮了VANET的節(jié)點(diǎn)密度。GPCR-D能夠動(dòng)態(tài)判定節(jié)點(diǎn)密度,并且實(shí)時(shí)建立和維護(hù)節(jié)點(diǎn)密度大的局部區(qū)域。在節(jié)點(diǎn)密度大的局部區(qū)域內(nèi),車輛移動(dòng)速度較慢,拓?fù)浣Y(jié)構(gòu)相對(duì)穩(wěn)定,采用最短路算法進(jìn)行路由;處于局部區(qū)域以外的節(jié)點(diǎn)仍然采用貪婪思想轉(zhuǎn)發(fā)。同時(shí),本論文改進(jìn)了GPCR中的“空洞問(wèn)題”和恢復(fù)策略,右手定所選出的下一跳路由很有可能朝著遠(yuǎn)離目的節(jié)點(diǎn)的方向轉(zhuǎn)發(fā),改進(jìn)后的恢復(fù)策略結(jié)合了車輛的位置與角度。在需要Qos保證的VANET環(huán)境下,單一信道競(jìng)爭(zhēng)的MAC協(xié)議面臨非常嚴(yán)重的挑戰(zhàn),它已經(jīng)不能滿足網(wǎng)絡(luò)容量和傳輸速率更高的需求。多信道的MAC協(xié)議應(yīng)用而生。本論文提出考慮了節(jié)點(diǎn)密度和服務(wù)流量的多信道MAC協(xié)議,在保證通信性能的前提下,盡可能少的減少切換次數(shù)。節(jié)點(diǎn)密度較大,并且服務(wù)信息流量較大的節(jié)點(diǎn)劃分為α模式;當(dāng)節(jié)點(diǎn)密度較大,但服務(wù)信息流量較小時(shí)劃分為β模式;其余情況的節(jié)點(diǎn)劃分為γ模式。根據(jù)不同模式的特點(diǎn),采用不同的報(bào)文發(fā)送模式,并且給出三種模式之間的判定和切換方法。對(duì)于α模式,給出動(dòng)態(tài)調(diào)整周期數(shù)的PID算法和自適應(yīng)算法。在保證安全信息的可靠傳輸條件下,對(duì)SCH信道進(jìn)行合理分配,保證安全信息的發(fā)送,盡可能地滿足用戶的服務(wù)需求,提高數(shù)據(jù)帶寬。最后,本論文在OMNET++平臺(tái)上,以SUMO為交通模擬器。選用Veins這款開(kāi)源的車輛間通信模擬仿真框架,仿真了GPCR-D和多信道MAC協(xié)議。實(shí)驗(yàn)結(jié)果表明,數(shù)據(jù)包投遞率和傳輸時(shí)延都得到了改善,具有較好的通信性能。
[Abstract]:With the increasing number of vehicles and increasingly crowded streets, traffic safety can not be effectively guaranteed. The problems of environment and energy shortage need to be solved urgently. These sharp problems have brought a lot of economic loss to the country. The concept of VANET has been born in the process of constantly trying and exploring. It is aimed at the vehicle as the node. The communications network. Compared with the traditional Ad Hoc network, there are many different characteristics. The speed of vehicle moving in VANET is relatively fast, the connection relation of the network changes in real time, and the density distribution of nodes is different. And wireless communication is easily blocked by obstacles such as high-rise buildings. Traditional routing and MAC protocols are no longer applicable to VANET.However, they directly affect the message delivery rate and delay. Therefore, it is imperative to study the routing and multi-channel MAC protocols. In the second chapter, this paper summarizes the current research progress of VANET routing. The advantages and disadvantages of different types of routing are analyzed. The routing of GPCR-D is proposed in this paper. Different from the traditional location-based routing, it considers the node density of VANET. GPCR-D can dynamically determine the node density. In the local area with high node density, the speed of vehicle moving is slow and the topology is relatively stable, so the shortest path algorithm is used to route. The nodes outside the local area still use greedy thought to forward. Meanwhile, this paper improves the "cavity problem" and the recovery strategy in GPCR. The next hop routing selected by right-handed decision is likely to be forwarded away from the destination node. The improved recovery strategy combines the position and angle of the vehicle. In the VANET environment which needs Qos guarantee. The MAC protocol of single-channel competition is facing a very serious challenge. It can not meet the demand of higher network capacity and transmission rate. Multi-channel MAC protocol is applied. This paper proposes a multi-channel MAC protocol which takes into account the node density and service traffic. On the premise of ensuring the communication performance, the number of handoffs is reduced as little as possible. The nodes with high node density and large service information flow are divided into 偽 mode. When the node density is high, but the service information flow is divided into 尾 mode. The nodes in the other cases are divided into 緯 modes. According to the characteristics of different modes, different message sending modes are adopted, and the methods of judging and switching between the three modes are given. The PID algorithm and adaptive algorithm for dynamically adjusting the number of periods are given. Under the condition of ensuring the reliable transmission of the security information, the SCH channel is allocated reasonably to ensure the transmission of the security information. As far as possible to meet the service needs of users, improve the data bandwidth. Finally, this paper on the OMNET platform. With SUMO as the traffic simulator, Veins, an open source simulation framework for inter-vehicle communication, is used to simulate GPCR-D and multi-channel MAC protocol. The experimental results show that. The packet delivery rate and transmission delay are improved and have better communication performance.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：U495;U463.67;TN929.5

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相關(guān)期刊論文 前1條

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本文編號(hào)：1420773