ASIP implementation of CDI feedback and low complexity precoding for MU-MIMO system

In this paper, we propose a low complexity MU(multi-user)-MIMO precoding method and show ASIP (application specific instruction-set processor) implementation results of both CSI (channel state information) feedback and our precoding method. To realize DL(downlink)-MU-MIMO transmission, the MU-MIMO precoding and CSI feedback are required in AP (access point) and STA (station) respectively for canceling IUI (interuser interference). However, conventional IBD (iterative block diagonalization) precoding has a high computational complexity problem. Therefore, we propose an LC(low complexity)-IBD precoding method whose complexity is reduced by using null vectors from CSI decompression process. The implementation results show that our precoder can reduce computational complexity and latency.