Limited feedback multiuser MISO systems with differential codebooks in correlated channels

In this paper, we present a differential codebook design by modifying the Grassmannian codebook for a single-cell multiuser (MU) multiple-input single-output (MISO) system operating under spatially and temporally correlated channels. The differential codebook design involves scaling and rotation methods that help a codebook to track the slow varying channel. We propose an adaptive scaling technique that improves the performance of the system in correlated channels without any additional feedback information. Monte Carlo simulations show that the proposed differential codebook reduces quantization errors and improves sum-rate performance as compared to other differential codebooks designed for spatially and temporally correlated MISO channels.