Research On Multi-User Coordinated Multi-Point Transmission In LTE-A

Since the advanced physical layer technology of LTE is still applied in LTE-A, SC-FDMA and OFDMA are used as uplink and downlink multiple access methods. Different Users in one cell can be separated by orthogonal subcarriers so that intra-cell interference can be diminished. But inter-cell interference which is caused by all cells using the same frequency band still exists, and it becomes the key factor that affects system performance. In order to mitigate inter-cell interference and meet the performance standards of4G,3GPP proposed the Coordinated Multi-Point Transmission/Reception technology. Through coordinated scheduling or joint transmission among multiple cells, it can effectively mitigate inter-cell interference, improve edge users’throughput and even cell average throughput, expand high data rate coverage and provide better QoS for edge users.This paper mainly studies the Multi-User CoMP in CoMP Joint Processing technology. The author’s work mainly includes the following aspects. The first is the research of some CoMP key technologies. Through reading a lot of relevant3GPP standards, proposals and theses, the author summarizes the basic principles of CoMP, feasible network architectures, transmission modes, clustering schemes and feedback mechanisms. Some key issues and solutions in these fields are discussed. The second is the research of some MU-CoMP key technologies includes cluster selection, precoding design, downlink user matching methods and resource scheduling algorithms. This paper mainly proposed a semi-static rotated cluster selection strategy for MU-CoMP. All cell edge users can get more equitable opportunities to benefit from CoMP and all frequency resources are available for MU-CoMP. This paper also introduces a score-based resource scheduling algorithm in MU-CoMP. Each user scores for every resource blocks in the system based on the effect of using them, and the resource blocks are allocated according to the scores that different users can get. This method can get better scheduling performance. The third is MU-CoMP performance simulation and evaluation. MU-CoMP function modules are designed and implemented on a LTE system simulation platform for ideal channel estimation MU-CoMP simulation.3-cells MU-CoMP in static cluster and the proposed semi-static cluster under different user matching methods and scheduling algorithms are evaluated. The simulation results show that the proposed schemes can get better performance.