Stationarity Investigation of a LOS Massive MIMO Channel in Stadium Scenarios

Massive multiple input and multiple output (MIMO) systems can increase the spectrum and energy efficiency of existing cells, and because of this, massive MIMO has been considered as a potential technique for next generation wireless communication networks. Since a thorough knowledge of the propagation channel is a prerequisite of reliable communication systems, massive MIMO channels are of great current interest. In this paper, based on realistic measurements in a stadium scenario in two frequency bands, the stationarity of three basic channel parameters is investigated by using the reverse arrangements test. The results show that channel behaviors in our higher frequency band are stationary over the linear antenna array, whereas this appears untrue at the low frequency band. This non-stationarity phenomenon in the line of sight propagation environment is mainly caused by the stronger reflection and smaller path loss at the low frequency band, which allows more and stronger multipath components, and this leads to substantial channel changes over the large size antenna array.