IEEE 802.16m中的HARQ技术研究

【作者】 张辉；

【导师】 周亮；

【作者基本信息】 电子科技大学 ， 通信与信息系统（专业学位）， 2012， 硕士

【摘要】 2005年,IEEE推出了具有移动化、宽带化和IP化的特点的IEEE802.16e标准,但是传输速率不断提高的需求使得IEEE802.16e的局限性不断表露出来,因此具有两倍频谱效率的、兼容IEEE802.16e的IEEE802.16m应运而生。HARQ技术是实现移动通信系统高吞吐率和高可靠性的关键技术之一,也成为IEEE802.16e与IEEE802.16m的标准技术内容。本文的主要工作和成就简述如下。(1)在简要介绍HARQ技术的基本原理基础上,详细描述了IEEE802.16m协议中定义的HARQ技术规范。(2)研究了IEEE802.16m协议中的信道编码技术,并对其采用的CTC码的性能做了仿真,分析表明迭代次数的增大使得CTC码的性能不断提高,但所获得的增益越来越小。(3)重点研究基于CTC码的符合IEEE802.16m协议规范的HARQ算法与性能评估,涉及内容有：CRC编码／校验、CTC编／译码、速率控制、HARQ重传控制、调制／解调、星座重排、AWGN信道、HARQ合并等处理模块。(4)重点研究了IR和Chase两种码合并算法,并对采用这两种算法的HARQ系统做了仿真,分析表明在调制阶数和编码码率较低时,IR合并相比Chase合并性能增益有限,但随着编码码率和调制阶数的增大,IR合并相较于Chase合并的性能优势越来越明显。(5)介绍了一种减少HARQ传输时延的方法,并对这种方法做了仿真分析,证明该方案可有效降低时延。(6)研究了AMC与HARQ相结合技术,并搭建了该技术的仿真平台,采用6种MCS,分别为QPSK(1/2,3/4)、16QAM(1/2,3/4)、64QAM(2/3,3/4),分析表明AMC-HARQ技术性相比AMC技术,在自适应准确性高时所取得的性能增益不大,而在自适应误差较大时,优势更为明显。更多还原

【Abstract】 In2005, IEEE introduced the IEEE802.16e standard with the characteristics of mobile, broadband and IP. As the request of users for the mobile transmission rate constantly rises, the IEEE802.16e standard show its limitations. Therefore, as the enhanced version of the IEEE802.16e, IEEE802.16m, which provides two times spectrum efficiency of IEEE802.16e, arises at the historic moment.HARQ is the key technology of wireless mobile communication and plays a very important role in realizing the mobile communication system with high throughput rate and high reliability. Therefore, HARQ is introduced to the standards IEEE802.16e and IEEE802.16m.The main work and achievements of this paper are briefly described as follows.First, the basic principles of HARQ and the HARQ technology used in IEEE802.16m standard are introduced in this dissertation.Second, we study the channel coding used in IEEE802.16m. The results of simulations show that with the increase of number of iterations, the performance of CTC improves, but the gain becomes smaller.Third, this dissertation designs a simulation platform of the HARQ system based on CTC code used in IEEE802.16m standard, involving CRC,CTC,HARQ retransmission,modulation and demodulation,constellation rearrange, AWGN channel and HARQ combination.Furthemore, we study the IR combination and Chases combination used in HARQ system.Through the simulating,we find that when we adopt a lower modulation order and a lower coding rate, the gain of IR combination compared with Chase combination is limited, but with the coding rate and modulation order increasing, the gain of IR combination compared to Chase combination increases gradually. This dissertation also introduces a method to reduce the delay of HARQ transmission which is proved to be effective.In the end, we study the AMC and HARQ combination technology.We adopt six kinds of MCS, including QPSK (1/2,3/4),16QAM (1/2,3/4) and64QAM (2/3,3/4).Compared with AMC technology, the gain of AMC-HARQ is limited when the adaptive accuracy is high, but it is considerable when the adaptive error is serious.更多还原