Abstract
This paper investigates codebook-based precoding for spatial modulation (SM) systems to improve the performance, reduce the feedback overhead and dispense with Channel State Information at the Transmitter (CSIT). Phase-only codebook with systematic structure, that is independent of the CSIT, is proposed. This codebook could meet published performance of SM codebook precoding with same or lower feedback overhead and simpler implementation. When supplemented with the proposed gain-only codebook, the performance improves further at the cost of small additional feedback overhead.