Multiuser Correlation and Sum-Rate in Outdoor Measured Massive MIMO Channels

This letter analyzes the impact of interuser distance and angular separation on the channel correlation and achievable sum-rate for a massive multiple-input-multiple-output (MIMO) system in non-line-of-sight (NLOS) conditions. The investigation is based on outdoor measurements on a channel sounding system capturing the dynamic channel of two user arrays. The letter analyzes correlation and sum-rate with varying interuser distance and angular separation of dominant beams toward the users. A large span of correlation and sum-rate values are found across the range of distances and angular separation. The investigation shows a moderate link between interuser distance and correlation, but a strong impact on correlation is found only for low angular separation of the users. The results of this NLOS scenario suggest that a distance-based criteria alone is not sufficient to accurately model shared clusters and their correlation.