A PMI Feedback Scheme for Downlink Multi-User MIMO Based on Dual-Codebook of LTE-Advanced

In order to achieve a better tradeoff between overhead and performance, this paper proposes a separately selected dual-codebook (SSDC) based best companion cluster (BCC) approach. In this scheme, each UE selects its best and worst longterm precoding matrix indicators (PMI1), and feeds them back as the cluster indicators (CIs) for UE pairing. The final precoder W is determined by two precoders indicated by the best PMI1 and the short-term feedback PMI2. Besides, channel quality indicators (CQIs) are calculated for UE scheduling. To compare with SSDC-based BCC, we also discuss and propose a jointly selected dual-codebook (JSDC) based BCC scheme. Simulation results show that SSDC-based BCC has a comparable throughput performance with JSDC-based BCC but with a substantially reduced complexity and feedback overhead for 8Tx.