Precoder design for distributed antenna systems based on channel angular domain information

With the goal of further improve the performance of distributed antenna system (DAS), linear precoding along with orthogonal space time block codes (OSTBCs) is introduced to exploit the diversity and coding gains simultaneously. In particular, we propose a novel precoder design method based on channel angular domain information, such as average angle of arrival (AOA), angular spread (AS) and normalized antenna spacing (NAS). The major advantages of this method reside in that it clearly reveals the relationship between the optimal precoder and practical propagation environment. More importantly, it requires very small amount of feedback while guaranteeing good performance. Furthermore, the asymptotical behavior of the performance is analyzed to achieve a suboptimal precoder design method with low complexity. In addition, the impact of angular domain parameters on system performance are investigated in some detail. Finally, numerical results verify the effectiveness of our proposed scheme.