Performance Evaluation of Mobile Phone Antennas in Physical MIMO Channels Using Polarized Spherical Harmonic Decomposition

Modern wireless communications systems fall on the use of multiple antennas at both link ends in order to achieve increased spectral efficiency and high data rates. Recent works have studied the interaction between the antenna array model and the wave propagation scenario in order to provide insight into spatial degrees of freedom of multiple-antenna communication systems. This paper presents a polarization-sensitive MIMO channel decomposition model using spherical harmonics expansion. This approach allows the separation of co- and cross-polarized end-to-end MIMO channel responses into three components: transmit antennas´ response, multipath propagation, and receive antennas´ response. Besides the inclusion of polarization in the modeling, the novelty is the presence of time delay. Computer simulations are provided to evaluate the correlation and capacity of practical mobile phone antenna setups in conjunction with the WINNER II channel model, exploring the usability of the improved model.