Research On Precoding And Scheduling For CoMP Downlink In LTE-A

LTE-Advanced (LTE-A) is the LTE (Long Term Evolution) Evolution version. CoMP, as one of the key technologies in LTE-A system becomes the research hotspot gradually in recent years. CoMP which makes use of coordinated transmission among multi-cells, effectively solves the problem of multi-cell edge interference, improves the throughput of cell edge, and thereby expands coverage of high-speed transmission. In the downlink of CoMP transmission system, precoding and user scheduling are the keys to obtain multiplexing gain and diversity gain. Precoding can suppress interference among users and reduce the complexity of the user's receiving treatment. User scheduling can choose some good user channel conditions to improve the system capacity.The paper introduces theoretical basis of CoMP technology, classification and standardization process briefly. It mainly studies precoding algorithms of CoMP transmission system, including three precoding methods (ZFBF, MMSE and BD), proposes improved precoding algorithms and carries on theoretical analysis and performance simulation comparison. Then it also studies user scheduling of CoMP transmission system, including single-user and multi-user scheduling algorithm. For single-user scheduling, it uses traditional PF scheduling algorithm to compare performance of CoMP with traditional MIMO system, but for multi-user scheduling, it studies optimization and sub-optimization algorithm, and proposes new scheduling algorithm based on independent cell in CoMP to reduce the complexity of the CoMP trannsmisson system.