LTE系统干扰管理研究

发布时间：2018-01-16 11:30

本文关键词：LTE系统干扰管理研究　出处：《北京交通大学》2014年博士论文　论文类型：学位论文

【摘要】：随着无线通信技术的高速发展,用户希望通信网络在保持移动性与覆盖性的同时,实现低速场景下的高速数据接入业务。长期演进(Long Term Evolution, LTE)系统支持多种带宽,可以满足不同业务的速率要求；重视用户数据业务体验,相比传统网络可以提供更高的峰值速率和用户吞吐量；增加小区边界传输速率,保障用户在任何时间任何地点的数据业务有效接入。LTE网络的这些技术特性,契合了用户对于数据业务的需求,具有良好的应用前景。在提供高质量数据传输业务的同时,LTE网络也对频谱效率提出了更高的要求,但是频率资源复用而产生的网络干扰会成为限制系统性能的重要因素。干扰管理可以在保证频谱效率的同时,通过系统级频率规划和链路级信号处理技术,提高网络与用户的通信质量,使其成为近几年的研究热点。本文以LTE系统为背景,重点研究了干扰协调技术、干扰消除技术,并对LTE网络的干扰来源、干扰特点以及干扰指标进行了分析和优化。论文的主要研究内容与创新点如下： (1)针对中心用户性能未受到额外关注的问题,提出了一种新的部分频率复用结构,进一步降低了产生同频干扰的概率。该结构在保证小区边缘用户资源正交的前提下,将小区中心用户的资源分为专用频段与共用频段两部分,并为专用频段设置更高的优先级。相比传统分配算法,该结构在注重边缘用户性能的同时,也重视中心用户的体验。中心用户在使用专用频段时,享有更高的发射功率,提高了有用信号占比；同时,边缘用户的干扰来源减少,降低了受到同频干扰影响的几率。在确定资源分配策略后,分别对中心用户和边缘用户的信道容量、系统吞吐量、中断概率以及干扰矫正因子四个参数进行定量分析。 (2)针对中心用户与边缘用户资源占用比例不均衡的问题,在部分频率复用结构基础上,提出了一种自适应资源调整算法。通过对已分配资源的动态调整,使得中心用户与边缘用户的资源比例更适合实际通信环境,或在突发状况发生时实现不同的资源分配侧重。资源的调整比例根据用户受到的干扰情况而设定,系统可以利用权重因子调节动态资源的最大比例或决定是否采用动态策略。在两种部分频率复用结构中分析了提出的算法,并对比了两种结构中算法实现的差异性。仿真结果从吞吐量、用户信道状况、误码率等角度对算法性能进行了评估。 (3)针对系统对于干扰消除技术计算复杂度的顾虑,提出了一种上行链路接收端执行的干扰消除算法。接收机通过重构和移除干扰信号,使更新后的原始接收信号只包括有用信号与噪声。算法在对计算复杂度和成本不敏感的基站一侧执行,不会给用户终端带来额外的开销。同时,在信道状态未知的情况下,算法利用训练序列的传输结果和插值方法完成数据信号的信道估计,更具实际应用价值。仿真结果验证了提出的干扰消除算法在不同载波分配方式下的有效性,并分析了不同通信场景中的算法特性。 (4)在分析LTE网络干扰来源的基础上,对干扰指标中的信干噪比参数进行了深入研究。从用户角度出发,建立了权衡吞吐量利用率和用户花费的效用函数,设立兼顾性能体验和网络开销两方面影响的优化目标,引导用户在两者间理性权衡自身需求。通过建立效用函数的微分博弈模型,利用微分博弈算法求解时间连续型效用函数的最优解,得到用户权衡通信质量与开销后的信干噪比决策。利用仿真讨论了算法在不同干扰场景中的性能表现,阐释了造成算法性能差异的原因。
[Abstract]:With the rapid development of wireless communication technology, users want to keep communication network in mobility and coverage at the same time, the realization of high speed data access speed scenarios. The long-term evolution (Long Term Evolution, LTE) system to support a variety of bandwidth, can meet the different rate of business requirements; pay attention to the user experience of data services, compared with the traditional network can provide the peak rate and throughput is higher; increase the transmission rate of the cell boundary, the characteristics of technology to protect the user at any time and place the data business effective access.LTE network, fit the user demand for data services, has the good application prospect in providing high quality data transmission business at the same time, LTE network is also proposed higher requirements for spectrum efficiency, but the network interference caused by frequency reuse will become an important factor restricting the performance of the system . interference management can guarantee the spectral efficiency at the same time, the system level and link level frequency planning and signal processing technology, improve the quality of communication network and the user, make it become a research hotspot in recent years. Based on the background of LTE system, focus on the interference coordination technology, interference cancellation, and interference source of LTE network, interference characteristics and interference parameters were analyzed and optimized. The main research contents and innovations are as follows:
(1) the center has not received extra attention to user performance problems, and proposed a new partial frequency reuse structure, further reducing the probability to produce the same frequency interference. The structure in the premise of ensuring the user resources under the orthogonal edge area, the cell center users resources is divided into two parts with special frequency band sharing frequency band. And set a higher priority for the special frequency band. Compared with the traditional algorithm, the structure on the edge user performance at the same time, the center also attaches great importance to the user experience center. Users in the use of special bands, enjoy a higher rate of transmission power, improve the proportion of useful signals; at the same time, reduce the interference of edge users. Reduces the chances of being the same frequency interference effect. In determining the resource allocation strategy, the channel capacity of center users and edge users respectively, system throughput, outage probability and interference correction factor four The parameters are analyzed quantitatively.
(2) for center users and user resources edge occupies the proportion of balance problem. Based on the structure of partial frequency reuse, we propose an adaptive resource adjustment algorithm. Through the dynamic adjustment of the allocated resources, the center users and edge users the proportion of resources is more suitable for the actual communication environment, or the allocation of resources to achieve different in the emergency situation occurs on. Adjust the proportion of resources and set according to the interference by the user, whether the system can adjust the dynamic resource utilization factor is the largest proportion of weight or decided to adopt a dynamic strategy. In the two part frequency reuse structure is analyzed in the proposed algorithm, and the comparison between algorithms of the two structures. Simulation results from user channel conditions, throughput, bit error rate angle to evaluate the performance of the proposed algorithm.
(3) the system for interference elimination in computational complexity concerns, proposes an uplink interference receiver implementation of the algorithm. The receiver through the reconstruction and remove the interference signal, so that the original received signal after the update includes only the useful signal and noise. The algorithm is not sensitive to the complexity and cost of the implementation of the base station side that will not bring additional overhead to the user terminal. At the same time, in the case of unknown channel state, channel transmission results algorithm using training sequence and interpolation method to complete the data signal estimation, more practical value. The simulation results verify the effectiveness of the proposed interference cancellation algorithm in different carrier allocation mode, and analysis the algorithm characteristics of different communication scenarios.
(4) based on the analysis of LTE network interference source, interference index in SNR is studied. Parameters from the user perspective, establishes the utility function balance throughput utilization and cost of the user, the establishment of both optimization goal influence performance of the two aspects of experience and network overhead, to guide the user in the rationality of balancing their needs. Through the establishment of differential game model of the utility function, the optimal time by solving differential game algorithm of continuous utility function solutions, users get the balance between communication quality and cost after SINR decision. Using simulation algorithm is discussed in the performance of different interference scenarios, causes performance difference algorithm the explanation.

【学位授予单位】：北京交通大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TN929.5

【参考文献】