Study on codeword selection for per-cell codebook with limited feedback in CoMP systems

Per-cell codebook based precoding is an effective transmission method in coordinated multi-point (CoMP) systems with the limited feedback constraint. There are two codeword selection methods for per-cell codebook, one is joint codeword selection (JCS) and another is independent codeword selection (ICS). In this paper, the system throughput obtained by the JCS and the ICS is analyzed firstly, which shows that JCS has a better trade-off between system throughput and feedback overhead. Then a codebook compression scheme for the JCS is proposed, which decreases the selection complexity of JCS by reducing the size of the codebook. Simulation results show that the proposed scheme can decrease the selection complexity greatly with tiny loss on performance and no additional feedback overhead.