Layer arrangement for single-user coordinated multi-point transmission

Coordinated multi point transmission is an attractive technology to minimize interference in single frequency networks and such to improve data rates. In this paper, we study closed-loop single user joint transmission (JT-MIMO) system. We propose to feedback a layer arrangement matrix together with per transmission point channel state information (CSI). In case of two layers, we provide a simple method to find an optimal layer arrangement. Furthermore, we propose a low complexity algorithm when an exhaustive search over the different layer arrangements becomes unbearable. System level simulation results show that the flexible layer arrangement outperforms traditional rank adaptation with only small amount of additional feedback.