【作者】 周康；

【导师】 盛敏； 刘瑾；

【作者基本信息】 西安电子科技大学 ， 工程硕士（专业学位）， 2017， 硕士

【摘要】 随着移动通信技术的发展与互联网信息时代的到来,移动通信业务已经从单纯的语音业务发展成为结合互联网的多媒体业务类型,如何能高效地利用带宽资源成为了无线通信系统设计中必须重视的问题,而高性能通信系统的实现在很大程度上依赖于资源调度算法的高效性。考虑到当前无线通信技术的迅猛发展以及新型多媒体业务对通信系统的严峻要求,本文对LTE系统下行资源调度算法进行了研究与实现。目前的资源调度算法,在涉及到子带CQI(Channel Quality Indicator)上报时,通常使用EESM(Exponential Effective SIR Mapping)的CQI等效方法,并且调度算法按照先分配完RB(Resource Block),然后对CQI等效的串行过程进行。本文首先对CQI等效技术进行研究,针对于EESM算法复杂度高以及等效后的CQI可能与实际环境不匹配的缺点,在原有线性HM(Harmonic Mean)算法的基础上,针对无线环境变化快的特点对等效后的CQI进行改进,提出了一种改进型的HM方法,使得等效后的CQI与实际环境更匹配。在此基础上,提出了一种CQI等效和资源分配联合考虑的下行资源调度算法,在资源分配的同时考虑CQI等效带来的损失,通过合理的分配资源块,提高无线资源的利用率,同时考虑了用户的公平性,最终通过借鉴启发式算法蚁群算法的思想进行实现。具体研究内容与研究成果如下:1.对HM算法进行了理论上的性能分析,并针对于CQI估计误差、无线环境变化快的问题对原有线性的HM算法进行基于用户反馈ACK的改进,然后结合实验室实际的LTE平台设计编写了LTE下行系统的CQI等效程序,对HM算法的有效性以及改进后HM算法的性能进行了验证;2.建立了LTE下行资源分配中公平性、吞吐量性能指标的数学模型,通过公式之间的制约构建了资源分配过程中考虑公平性的同时最大化系统吞吐量的最优化问题,在此基础上提出了下行资源调度过程中资源分配和CQI等效并行考虑的思想,并对资源调度的流程进行了实现;3.将本文提出的资源分配与CQI等效联合考虑的调度算法与现有最大吞吐量算法和轮询算法进行了系统吞吐量、用户公平性、频谱利用率等多个指标的对比和仿真,并基于实验室实际的LTE平台,将改进型的HM算法应用于本文所提的联合调度算法中,对本文算法的公平性与吞吐量指标进行了验证。更多还原

【Abstract】 With the development of the mobile communication technology and the advent of the mobile Internet era,the mobile communication business has been developed from the simply voice of business to multimedia service types combined with the internet,how to use the bandwidth resource efficiently must be paid more attention for the designers of the wireless communication system and the communication system’s efficiency largely depends on the resource scheduling and allocation algorithm.Considering that wireless technology has a rapid growing and the new multimedia services has a severe demand on the communication system,this paper studies and implements the downlink resource scheduling algorithm of LTE system.In terms of sub-band CQI distribution,we usually use the EESM method to map the CQI and the current scheduling algorithm usually distributes RB first and then maps the CQI in serial process.This paper first conducts the research about the CQI mapping,and for the shortcomings of high complexity and the mapped CQI may not match the actual environment for EESM,this paper implements an improved linear method of HM which is based on the original linear HM algorithm,this method will adjust the mapped CQI to match the actual environment according to the characteristics of wireless environment.On this basis,a downlink resource schedule algorithm which combines the RB distribution with the CQI equivalent is proposed.When the base station distributes RB for the user,the loss of the CQI equivalent will be considered at the same time,through the rational allocation of resources,the resource utilization is improved,moreover,this scheduling algorithm considers the fairness of the users as well.Finally,we realize the idea by using heuristic algorithm of ant colony algorithm.Specific research contents and results are as follows:1.Analysis the HM algorithm performance in theory,and in view of the CQI estimation error and the rapid change of the wireless environment,we fine-tune the CQI after it is equivalent based on the ACK from the user,then design and implement the CQI mapping algorithm based on the actual LTE platform of our laboratory,though user equipment access,the effectiveness of the HM algorithm and the performance of the improved HM algorithm are verified;2.The dissertation establishes the mathematical model of user fairness and throughput index in LTE downlink resource allocation,and we build an optimization problem to maximize the throughput and consider the fairness as well by the restrict between formula,then on this basis,we propose the idea of combining allocation with CQI mapping in the process of the downlink resource scheduling;3.Compare the proposed algorithm with the existing algorithm for maximum throughput and round robin algorithm in system throughput,user fairness,and the spectrum utilization index in theory,and finally,we apply the improved HM CQI mapping method to the proposed scheduling algorithm and verified the superiority of the proposed algorithm in fairness and throughput index based on LTE platform in our laboratory.更多还原