Research On Key Techniques Of Radio Resource Allocation In Relay-enhanced Cellular Networks

The discussion of the frequency spectral efficiency of LTE systems is devided into two aspects:the frequency spectral efficiency of cell edge user and the frequency spectral efficiency of intra-cell user. Because of inter-cell interference,the spectral efficiency of cell edge user is severely reduced. 3GPP studied and proposed Coordinated Multi-Point Operation(COMP) for LTE systems, this important technology is able to solve she problem of inter-cell interference, it select several base stations cooperatively transmit data. This shesis focuses on the research of COMP as follow:Firstly, the thesis introduces basic concepts and system architecture of COMP, including:COMP scenarios, COMP sets, COMP categories. The thesis also introduces several existing channel state information feedback scheme.Secondly, the thesis studies the downlink COMP precoding technique under Limited-Capacity Backhaul. The contents of this chapter is about codebook generation and codebook selection of COMP precoding. The thesis compares three kinds of codebook generation algorisms and two kinds of codebook selection algorisms. According to 3GPP protocol, this chapter built a TDD-LTE physical layer simulation link. Analyze and evaluate the performace of several algorithms mentioned above.Thirdly, the thesis studies COMP precoding technique base on signal detection of SRS. After the detection of SRS, we can obtain uplink channel information, Channel reciprocity is used to transform uplink channel information to downlink channel information. But due to RF link, channel reciprocity exist error. This chapter discusses the calibration of channel reciprocity. After channel reciprocity is adjusted, It can use several precoding algorisms to cooperatively transmit data, such as Zero forcing, BD-SVD, SLNR precoding algorism. This chapter simulation and compare the Ber performance of those algorithm.Lastly, the thesis study the implement of BD-SVD algorithm under CB-COMP categories. This chapter propose an optimization algorithm to implement BD-SVD by using Householder transform and Jacobi transform. On this basis,the thesis designs the BD-SVD hardware module using Xilinx KC705. Compare to other paper, this design have less calculation procedure and led to less resource consumption. The test of functional simulation and hardware test can verify the reasonableness of this design. Timing analysis results the maximum operating frequency of this BD-SVD circuit can reach 110.9Mhz, it can calculate the throughput of the entire module is 12.3M precoding/s, fully meet the needs of the cooperatively transmit between two base stations.