无线网络中M2M通信大容量接入研究

发布时间：2018-06-11 10:22

本文选题：M2M + 随机接入　；参考：《西安电子科技大学》2014年硕士论文

【摘要】：近年来物联网和消费电子的发展普及使得M2M通信作为一项新兴的技术应运而生,M2M通信能够为海量M2M设备提供全自动的信息传输和无处不在的网络连接,为了实现这一目的,就需要将M2M通信整合进当前的蜂窝无线通信系统。当前的蜂窝无线通信系统是专门针对H2H通信设计和优化的,而M2M与H2H通信在特性上有很大不同,包括业务方向,数据量大小,连接和接入时延,传输周期,移动性,信息优先级,设备数目,寿命和能量效率等。这些不同使得M2M通信向蜂窝无线通信系统中的整合面临很大的困难,如何优化空中接口已经成为了大范围部署M2M网络的首要问题,其中最重要也是最棘手的问题就是海量M2M设备的大容量接入问题。本文主要针对海量M2M设备在无线通信系统中的随机接入问题进行了研究,包括以下两个方面：1.提出了针对LTE系统中M2M通信大容量随机接入的优化算法。首先,根据LTE随机接入流程,建立假设模型,对LTE系统中的随机接入进行理论分析,推导出这些重要性能参数的数学表达式。再通过计算机仿真验证理论分析的正确性,并分析现有的LTE随机接入协议的性能。最后根据理论分析的结果,提出了大容量随机接入优化算法。算法为每一种M2M应用配置随机接入参数并分配随机接入时隙,在保证各个应用的接入成功概率和接入时延满足其服务质量要求的基础上,优化频谱效率和能量效率。计算机仿真结果体现了算法的有效性。2.基于IEEE 802.11协议,对无线局域网内的M2M通信大容量接入进行了研究。首先介绍了IEEE802.11中的几种媒介接入协议,包括DCF, EDCA,以及专门针对M2M通信提出的无线媒介接入标准IEEE 802.11ah。随后我们对这三种无线局域网接入协议从吞吐率,接入成功概率,碰撞概率,平均重传次数,能量消耗和时延方面进行了仿真比较,发现IEEE 802.11ah的确比DCF和EDCA协议更适合大量设备接入的情况,但它所提供的性能依然不能够满足每个接入点服务6000个设备的要求。因此我们对IEEE 802.11ah协议进行优化,通过减少RAW时隙的数目,增加RAW时隙的长度,来减少信道浪费,提升吞吐率。仿真结果显示在设备数目较多的情况下这种信道分配方式可以获得更优的性能。最后基于对仿真结果的观察分析,还给出了几种可行的提高IEEE 802. llah媒介接入性能的方案。
[Abstract]:In recent years, with the development of the Internet of things and consumer electronics, M2m communication has emerged as a new technology. M2m communication can provide automatic information transmission and ubiquitous network connection for mass M2m devices. It is necessary to integrate M 2m communication into the current cellular wireless communication system. The current cellular wireless communication system is specially designed and optimized for H2H communication, and M2M and H2H communication have very different characteristics, including service direction, data size, connection and access delay, transmission cycle, mobility. Information priority, number of devices, lifetime and energy efficiency, etc. These differences make it very difficult to integrate M2m communication into cellular wireless communication system. How to optimize the air interface has become the most important problem in the large-scale deployment of M2m network. One of the most important and most difficult problem is the mass M 2m equipment access problem. In this paper, the random access problem of mass M2M devices in wireless communication systems is studied, including the following two aspects: 1. This paper presents an optimization algorithm for mass random access to M 2m communication in LTE systems. Firstly, according to the LTE random access flow, a hypothetical model is established, and the theoretical analysis of random access in LTE system is carried out, and the mathematical expressions of these important performance parameters are derived. The correctness of the theoretical analysis is verified by computer simulation, and the performance of the existing LTE random access protocol is analyzed. Finally, according to the results of theoretical analysis, a large capacity random access optimization algorithm is proposed. The algorithm allocates random access parameters and random access slots for each M2m application, and optimizes the spectrum efficiency and energy efficiency on the basis of ensuring that the successful access probability and access delay of each application meet the requirements of quality of service (QoS). Computer simulation results show the effectiveness of the algorithm. 2. 2. Based on IEEE 802.11 protocol, the mass access of M 2m communication in WLAN is studied. Firstly, several media access protocols in IEEE 802.11 are introduced, including DCF, EDCA, and IEEE 802.11ah, a wireless media access standard for M2m communication. Then we compare the three protocols in terms of throughput, probability of success, probability of collision, average number of retransmissions, energy consumption and time delay. It is found that IEEE-based 802.11ah is better than DCF and EDCA protocols for a large number of devices, but its performance is still not able to meet the requirements of 6000 devices per access point. Therefore, we optimize the 802.11ah protocol to reduce channel waste and increase throughput by reducing the number of raw slots and increasing the length of raw slots. Simulation results show that this channel allocation method can achieve better performance when the number of devices is large. Finally, based on the observation and analysis of the simulation results, several feasible schemes to improve the performance of IEEE802. Llah media access are presented.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.5

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