Non-stationary Characteristics for Indoor Massive MIMO Channels

Massive Multiple Input Multiple Output (MIMO) has been widely considered as one of the most promising technologies for the fifth-generation (5G) wireless communication. In massive MIMO system, the research on channel characteristics is important. In this paper, the characteristics for massive MIMO channels at both 2GHz and 6 GHz are investigated. Based on the real-world measurements, the channel parameters in the delay and frequency domains are extracted to show the non-stationary phenomenon over the large-scale antenna array. Furthermore, the characteristics of the angular parameters extracted by space-alternating generalized expectation-maximization (SAGE) algorithm are investigated and the fluctuations are modeled. The results for different frequencies are useful for deep understanding of massive MIMO channels in the future.