Spatial Correlation in Indoor Massive MIMO: Measurements and Ray Tracing

This letter investigates spatial correlation properties of radio-frequency massive multiple-input-multiple-output (MIMO) channels. The between channel vectors at the receive side is studied for interreceiver distances up to several wavelengths. an important property 5G wireless networks and its accurate prediction desirable in many applications. Measured simulated channels are compared using alternative formulation function, argument which distance any two receivers proximity a selected region. measurements were conducted MIMO base station (BS) testbed virtual arrays receivers, positioned with robotic system. simulations performed ray-tracing (RT) technique simplified model indoor environment, augmented stochastic geometry elements. In addition, line-of-sight (LOS) was derived from RT results, role scattered power on evaluated. results show that predicts error not exceeding 10%. variation function profile increasing receiver BS separation also captured by model. LOS predictions, account solely direct propagation paths, found significantly underestimate subwavelength distance, overestimate it larger distances.