Research On Heterogeneous Networks Radio Resource Management For Lte-Advanced System

In order to meet the system requirements of the fourth generation mobile communication put forward by Radio communication Sector of International Telecommunication Union (ITU-R),3GPP began the standardization research work on the LTE-Advanced (LTE-A) system on the basis of LTE system. LTE-A system adopts heterogeneous networks (HetNet) and carrier aggregation (CA) technology to improve the performance of edge area and hotspots and make it more flexible to use the discrete spectrum. The methods above guarantee the demand of spectrum efficiency and transmission bandwidth for4G. However, CA has brought new problems in the scheduling between carriers, and the mobility management for the access frequency points. Besides, in HetNet with more complex structures, such as the dense small cells deployment scenarios within Rel-12, how to keep the load balance effectively and to avoid the interference between cells is a challenge and also has the practical significance.The content of this thesis is derived from the project the author taking part in during the postgraduate studying, which is a horizontal cooperation project between Beijing University of Posts and Tele-communications and an international well-known enterprise. In this project, the author participate in several patents invention work and study the relevant content of radio resource management, based on closely tracking the standardization status of LTE-A work group RAN2, RAN3. The main content of this paper includes the following two aspects: 1. Research on component carrier access and handover management strategies under CA. In this part I propose four kinds of different access strategy of primary component carrier, which transmits control signaling under the carrier aggregation, by delving into measurement object of carrier frequency from Rel-8/Rel-10, and trigger conditions and process on handover or changes of serving cells. Also depending on the difference of RRC signaling overhead, I propose three different management approaches for received primary/secondary component carrier (PCC). Simulates have been done to estimate above four kinds of PCC access strategy and three kinds of frequency handover management approach, which compare the total number of handover, handover failure rate, RRC reconfiguration frequency and other performance indicators under different conditions.2. Proposing load balancing scheme based on quality of service and interference conditions under small cell scenarios. Two possible reasons why resource status reporting is not exactly the information required for load balancing has proposed, which showed a load balancing ping-pong effect that is prone to occur in the scenarios of cells densely distributed. Load balancing scheme with guarantee Quality of Service (QoS) while taking into account the interference under HetNet small cells dense deployment scenarios is further proposed. I verified the advantage of balancing approach proposed in this paper from the aspects of throughput of small cells in clusters, overall user throughput, interference suffered by the user in clusters compared with the traditional method of mobility load balancing by simulation.