Adaptive Spherical-cap Differential Feedback Algorithm Based on Linear Operations of Vectors

In the MIMO systems, the differential feedback is an important strategy for temporally correlated channels. A new adaptive spherical-cap differential feedback algorithm is proposed for the Single-User Multiple Input Single Output (SU-MISO) systems. Firstly, this study effectively utilizes the channels disturbance between two consecutive time instants to design the adaptive differential feedback strategy. Secondly, based on vectors scaling and composition, a new spherical-cap differential codebook algorithm is proposed, which is different from the existing methods for constructing the non-linear model. Finally, the calculation method of spherical-cap radius is deduced by combining spatial distribution of the spherical-cap codebook with channels statistical regularity. The simulation results show that the proposed algorithm can accurately track the channel disturbance and has certain performance improvement than the existing algorithms.