An investigation into the effects of spatial correlation error on 5G MIMO OTA testing using single-probe anechoic chamber method

Multiple-input-multiple-output over-the-air testing evaluates the multi-antenna wireless systems' performance in a controlled laboratory environment by emulating realistic real-world fading channel conditions. Spatial correlation is the key metric to character the accuracy of MIMO OTA testing system. Along with the evolution into 5G era, the MIMO OTA measurement setup complexity increase as well, especially for accurate implementation of three-dimensional channel model. Furthermore, extension of the two-dimensional multi-probe anechoic chamber (MPAC) method into full spherical three-dimensional MPAC is impractical due to cost consideration and setup complexity. In this paper, we present the use of a cost-effective single-probe anechoic chamber (SPAC) method for MIMO OTA testing and demonstrate that better spatial correlation accuracy can be achieved over implementation of the 3D spatial channel model as compared with MPAC. The development of such method can significantly reduce implementation cost to support wireless device R&D process. Both the theoretical derivation and simulation results are validated.