The enhancement of MIMO capacity using angle domain processing based on measured channels

In this paper, the verification of using angle domain processing for Multiple Input Multiple Output (MIMO) system is presented. This paper proposes the concept of angle domain processing by applying a Butler matrix into 4 × 4 MIMO systems. A butler matrix is the most attractive technique for constructing angle domain due to its low cost and easy to implement. The measured results are compared with conventional MIMO system so called as array domain processing. The capacity performance indicates that the angle domain processing realized by Butler matrix outperforms the conventional system.