车载自组网中的信道接入机制研究

发布时间：2018-06-18 18:53

本文选题：服务信道接入 + 信道协作　；参考：《河南工业大学》2014年硕士论文

【摘要】：车载自组织网络是无线Ad hoc网络在车载环境下的重要应用。车载网络主要运用多信道操作模式来提供开放的安全服务和安全有效的驾驶体验，由此可见多信道接入在车载网络中占据非常重要的角色。吞吐量和时延是两个重要的指标。无线信道媒体接入控制（MediumAccess Control，MAC）机制是车载自组织网络的关键技术之一，也是车载自组织网络支持服务质量（Quality of Service，QoS）的关键。专用短程通信（DedicatedShort Range Communications，DSRC）使用的接入协议IEEE802.11p通过增强型分布式接入控制（Enhanced Distribution Coordinate Access，EDCA）及优先级划分来提供QoS保证。本文首先分析了车载自组织网络的现状及发展概况，介绍车载网络中的MAC协议标准，信道接入机制作为其关键技术之一，起着不可替代的作用。针对IEEE802.11p和1609.4中存在的问题，，分析了其接入原理，并对其性能做了简单的仿真分析。在IEEE802.11p MAC的基础上，根据车载自组网的特点和车辆相向行驶的特点，针对服务信道接入存在的缺陷，提出了一种基于信道通信间负载均衡和车辆间信道协作的自适应多信道接入机制MCAS，首先给出了系统模型，做了马尔可夫模型分析，从理论上分析MCAS的各项性能，并通过MATLAB仿真进行吞吐量、分组时延、丢包率等性能分析。结果表明，新算法的时延、丢包率和吞吐量都优于WAVE和VeMAC。该机制能够很好地利用控制信道与服务信道和服务信道之间的协作关系，更有效地利用信道，能够使之更好地适应车载网络环境。进而，又尝试使用混合的方法，即将CSMA和本文中的MCAS两种机制结合，来更好的运用于VANET中。将帧长划分为传输期和预留期两个阶段，传输期使用TDMA机制，预留期使用CSMA机制竞争信道。仿真结果表明，MCAS机制能在较大程度上改善网络性能，能够解决目前车载网中MAC协议所存在信道竞争和分配、传输时延、信道利用率、吞吐量等问题，使其可以很好的满足实际网络的应用。本文提出的方案在车载网络中有很重要的作用，对MAC协议的研究也有很大的帮助。
[Abstract]:Ad hoc network is an important application of wireless Ad hoc network in vehicle environment. Vehicle network mainly uses multi-channel operation mode to provide open security service and safe and effective driving experience, so multi-channel access plays a very important role in vehicle network. Throughput and delay are two important indicators. Wireless channel media access control (MAC) mechanism is one of the key technologies in vehicular ad hoc networks, and is also the key to support quality of Service (QoS) in vehicular ad hoc networks. IEEE 802.11p, an access protocol used by dedicated short-range short range Communications (DSRC), provides QoS assurance through enhanced Distribution coordinated access EDCAs and priority partitioning. This paper first analyzes the current situation and development of vehicle-borne ad hoc networks, introduces the MAC protocol standards in vehicular networks, and the channel access mechanism, as one of its key technologies, plays an irreplaceable role. Aiming at the problems existing in IEEE 802.11p and 1609.4, this paper analyzes the access principle of IEEE 802.11p, and makes a simple simulation analysis of its performance. On the basis of IEEE 802.11p MAC, according to the characteristics of vehicle-mounted ad hoc network and the characteristics of vehicle driving in opposite direction, aiming at the defects of service channel access, An adaptive multi-channel access mechanism (MCAS) based on inter-channel load balancing and inter-vehicle channel cooperation is proposed. Firstly, the system model is presented, and the Markov model is analyzed, and the performance of MCAS is analyzed theoretically. The throughput, packet delay and packet loss rate are analyzed by MATLAB simulation. The results show that the delay, packet loss rate and throughput of the new algorithm are better than those of wave and VeMAC. The mechanism can make good use of the cooperative relationship between the control channel, the service channel and the service channel, and make the channel more effective, so that it can adapt to the vehicle network environment better. Furthermore, we try to combine CSMA with MCAS in this paper to better use in VANET. The frame length is divided into two stages: transmission period and reservation period. TDMA mechanism is used in transmission period and CSMA mechanism is used to compete channel in reservation period. The simulation results show that the MCAS mechanism can improve the network performance to a large extent, and can solve the problems of channel competition and allocation, transmission delay, channel utilization, throughput and so on. So that it can be very good to meet the application of the actual network. The scheme proposed in this paper plays an important role in vehicle network, and it is also helpful to the study of MAC protocol.
【学位授予单位】：河南工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U495;U463.67;TN929.5

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