【作者】 程履帮；

【导师】 陶小峰；

【作者基本信息】 北京邮电大学 ， 信号与信息处理， 2011， 博士

【摘要】 LTE作为B3G的主要技术制式,目前在国际上已开始商用。TD-LTE是TD-SCDMA的演进技术,在频率资源受限的的情况下,也可以灵活地组网。因此,TD-LTE技术广受关注。资源调度和小区间干扰协调是LTE系统的主要技术难点,影响系统的容量和性能。RRM(Radio Resource Management,无线资源管理)的研究对象是移动通信系统的空中接口资源,目的是希望在无线资源有限的情况下,在保证一定的规划覆盖和QoS (Quality of Service,服务质量)的需求下,尽可能为更多的用户提供服务。如果没有良好的RRM技术,再先进的无线传输技术也无法发挥它的优势,甚至可能导致系统无法正常运转。而对于TDD系统,因为上下行位于同一频段,且对同步需求更高,因此对RRM的性能需求更高。本文的第一、二章简述了TD-LTE系统的背景及OFDM (Orthogonal Frequency Division Multiplexing,正交频分复用)系统关键技术特征,指出了RRM算法研究的目标以及本课题研究的方向。第三章对LTE业务信道以及控制信道的调度与资源分配进行研究。对于业务信道,本文提出了一种改进的RAD (Required Activity Detection,要求行为监测)算法,可以有效的支持混合业务的QoS要求,以BE(Best Effort,尽力)与VoIP业务为例进行了仿真分析。对于控制信道的调度与资源分配,本文考虑了PCFICH (Physical control format indicator channel,物理控制格式指示信道)与PHICH (Physical hybrid-ARQ indicator channel,物理混合重传需求指示信道)对PDCCH (Physical downlink control channel,物理下行控制信道)功率分配的影响,推导出了PDCCH等效数据导频比,并给出了PDCCH功率调整与CCE (Control Channel Element,控制信道单元)资源冲突检测的方法。通过仿真分析,所提出的方法能有效的提高控制信道的容量。本文还对层三相关的RRM问题进行了研究,具体包括ICIC (Inter-Cell interference cooperation,小区间干扰协调)和LBC (Load Balance Control,负载均衡控制)。通过对TD-LTE系统小区间干扰问题的研究,提出了半静态ICIC算法,该算法能够较好地根据用户数变化调整资源分配方案,获得良好的系统性能；而对用户划分标准的研究,则对系统性能的优化,给出了实现的设计方法。基于3GPP规范已确定的标准,提出了一种将静态资源划分与动态ICIC信息交互相结合的SFR (Soft Frequency Reuse,软频率复用)-DICIC算法,对于除小区负载较轻的情况外,该算法均能提供较好的性能。随着业务多样化以及用户数的增加,负载均衡对系统性能提升的影响越来越突出,本文针对TD-LTE系统内负载均衡问题展开了研究。设计了完整的负载均衡算法,仿真结果表明,合理的参数配置对LBC算法性能的提升至关重要,同时由于负载均衡过程需要X2接口信令的支持,过多的信令传输必然造成系统资源浪费。由本文提供的仿真结果可知,在负载较低时,启动LBC算法与不启动LBC算法的系统性能接近,而负载逐渐增加后,启动本论文提出的LBC算法,系统有显著的提升。最后,论文做了总结以及指出了继续深入研究的方向。更多还原

【Abstract】 As one of the primary standard of B3G (Beyond3G), LTE has been commercialized all over the world. As the evolution technology of TD-SCDMA, TD-LTE has got much more attention due to its flexible networking even the frequency resource is limited. In TD-LTE system, resource scheduling and inter-cell interference are the key technologies, which affluence the performance of system capacity. The studying object of RRM is air interface of wireless communication system, with its aiming to provide better coverage capacity and QoS under the limited wireless resources. Without RRM, even the advanced wireless transmission technology can not bring a good result, and may even cause the system crash down. For TDD (Time Division Duplexing) system, due to the frequency resource for uplink and downlink lies in the same frequency band and the system requires a higher level synchronization, RRM is much more important in RAN (Radio Access Network) system.Chapter1and2give a general description to TD-LTE system and some key technologies used in OFDM (Orthogonal Frequency Division Multiplexing) system, and also point out the objective of this thesis in RRM research.Scheduling and resources allocation schems for LTE traffic and control channel are introduced in chapter3. For traffic channel, an improved RAD (Required Activity Detection) method proved by simulation with BE (Best Effort) and VoIP service is proposed, which turns out could effectively support the QoS requirement for combination traffic. For the strategy of control channel scheduling and resource allocation, the effect of PCFICH and PHICH to PDCCH are taken into consideration and an equivalent data to reference signal power ration is inducted. The thesis also provides a new scheme which could adjust PDCCH power and CCE resourced collision detection. Simulation results show that the provided method can effectively improve the capacity of the control channel.Futhermore, we also analyze layer3and its related RRM problems, including ICIC (Inter-Cell interference cooperation) and LBC (Load Balance Control). Motivated by the analysis of interference problem in TD-LTE eNodes, a semi-static ICIC algorithm is proposed. This algorithm could effectively adjust resource assignment strategies according to the change status of users, so as to acquire better system performance. Studying on the principles to classify users helps to optimize the system performance. Based on3GPP specifications standards, a SFR-DICIC sceme is proposed, which combines static resource partition with ICIC information, provide better performance except for the lighter traffic case.Due to the diversity of service and increase of user, LB (Load Balance) plays a crucial role to improve the system performance. This thesis studies the LB problem in TD-LTE system. A complete LB algorithm is designed in our work. The simulation results indicate that reasonable parameter configuration is important to the LBC (LB Control) algorithm performance enhancement. The processing of LB needs the support of signaling between X2interfaces, but excessive signaling will waste the system resources. The simulation results indicate when the load is low, the system performance will not have distinct difference regardless if the LBC algorithm is activated or not. When the load becomes high, LBC can obviously improve the capability of system.Finally, a conclusion is given and direction for deeper research is pointed out.更多还原