LTE-Advanced系统中Small Cell干扰协调及其关键技术研究

发布时间：2018-07-05 02:27

本文选题：LTE-A + 小基站增强　；参考：《北京交通大学》2014年硕士论文

【摘要】：由第三代合作伙伴计划(the3rd Generation Partnership Project,3GPP)主导和推动的升级版长期演进(Long Term Evolution Advanced, LTE-A)已经成为当前广泛使用的第四代移动通信标准。LTE-A中采用了多天线增强、载波聚合、多点协作传输和中继通信等新技术,在频谱效率、系统带宽、峰值传输速率等方面较之前有了大幅度的提高。作为迄今为止发展最快的移动通信技术,LTE-A也不断面临着新的挑战。随着移动通信用户需求的不断激增,小型基站(Small Cell)成为业内大部分运营商和设备商扩展系统容量的首选解决方案。受到广泛关注的Small Cell增强技术有望在2014年6月写入3GPP Release-12技术规范中。 Small Cell的发射功率较小,可以部署在热点地区有效地提升系统容量、改善用户体验。Small Cell的应用带来了新的机遇,也引入了新的难题。Small Cell的大量部署会造成小区间交叠区域增加,由于LTE-A一般采用同频组网模式,交叠区域增加意味着小区间干扰加剧。为了应对小区间干扰,LTE中已经有了一些较为成熟的技术,如部分频率复用、软频率复用等,但这些技术对于Small Cell场景的增益十分有限而且部署难度很大。增强型小区间干扰协调(nhanced Inter-Cell Interference Coordination, eICIC)是LTE-A中引入的一种干扰协调技术,通过时域上的资源分配,配合小区范围扩展技术,可以在分流用户到Small Cell的同时改善Small Cell小区用户的信道条件,能够有效改善系统整体性能。本文还引入了一种新的载波类型(New Carrier Type, NCT),通过合理设计,能够压缩原有LTE-A系统中载波的参考信号的开销,由此可以减少能源消耗、提高资源利用率并进一步减少小区间干扰、获得系统性能的增益。不过,由于NCT压缩了公共参考信号,将导致LTE Release-8的用户无法正常工作,因此NCT不具备后向可兼容性,在标准化的进程中需要将谨慎考虑。为了准确评估技术方案的可行性和系统增益,本文采用了按照3GPP小型基站增强(Small Cell Enhancements, SCE)仿真场景搭建的LTE-A系统级仿真平台。本文将eICIC技术引入SCE场景中,并利用LTE-A系统级仿真平台分析了eICIC技术在SCE场景下的系统性能增益,给出了eICIC在SCE场景下的最优配置。本文还分析了新载波类型NCT的技术细节,通过理论推导和系统级仿真得到了NCT的开销压缩增益和干扰消除增益,验证了NCT在单纯宏基站覆盖和SCE场景下均能提供明显的系统性能增益。
[Abstract]:The long term Evolution Advanced (LTE-A), led and driven by the the3rd Generation Partnership Project 3GPP, has become the fourth-generation mobile communications standard widely used at present. LTE-A uses multi-antenna enhancement and carrier aggregation. The new technologies, such as multi-point cooperative transmission and relay communication, have greatly improved the spectral efficiency, system bandwidth, peak transmission rate and so on. LTE-A, the fastest developing mobile communication technology, is facing new challenges. With the increasing demand of mobile communication users, small Cell has become the preferred solution for most operators and equipment providers in the industry to expand system capacity. The small Cell enhancement technology, which has attracted wide attention, is expected to be written into the 3GPP Release-12 specification in June 2014. The small Cell has a low transmitting power and can be deployed in hot spots to effectively enhance the system capacity. The application of improving the user experience of Small Cell brings new opportunities, but also introduces new difficulties. The large number of deployment of small Cell will result in the increase of overlapping area between cells, because LTE-A generally adopts the same frequency networking mode. The increase of overlapping regions means that the intercellular interference is increased. In order to deal with the inter-cell interference (LTE), there are some mature technologies, such as partial frequency multiplexing, soft frequency multiplexing, etc., but these techniques have very limited gain for small Cell scenarios and are very difficult to deploy. Enhanced Inter-Cell interference Coordination (eICIC) is a kind of interference coordination technology introduced in LTE-A. At the same time, the channel condition of small cell users can be improved, and the overall performance of the system can be improved effectively. This paper also introduces a new carrier type (NCT), which can compress the cost of the carrier reference signal in the original LTE-A system by reasonable design, which can reduce the energy consumption, improve the resource utilization and further reduce the inter-cell interference. Gain the system performance. However, because the NCT compresses the public reference signal, will cause the LTE Release-8 user to not work properly, therefore the NCT does not have the backward compatibility, will need to consider carefully in the standardization process. In order to evaluate the feasibility and system gain of the technical scheme accurately, the LTE-A system level simulation platform based on the 3GPP small Cell Enhancement (SCE) simulation scenario is adopted in this paper. In this paper, the technology of eICIC is introduced into SCE scenario, and the system performance gain of eICIC in SCE scenario is analyzed by using LTE-A system-level simulation platform, and the optimal configuration of eICIC in SCE scenario is given. This paper also analyzes the technical details of the new carrier type NCT. The overhead compression gain and interference cancellation gain of NCT are obtained by theoretical derivation and system-level simulation. It is verified that NCT can provide obvious system performance gains under pure macro base station coverage and SCE scenarios.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.5

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