Polarimetric Characterization of MIMO Sub-6-GHz Self-Interference Indoor Radio Channels

This paper studies the behavior of self-interference radio channels associated with a $4 \times 4$ multiple-input-multiple-output antenna (MIMO) system. Self-interference channel measurements were performed in two indoor environments: Auditorium and reception hall. The captured measurement data are used to characterize ten concurrent self-interference channels - both co-polarized and cross-polarized channels. By means of vector network analyzer, one gigahertz of bandwidth, which occupies 2-to-3-GHz frequency band, is swept to sound these self-interference channels. The channel sounder was equipped with two dually polarized magnetoelectric dipole antennas that were utilized to observe the self-interference channels. Each of the dipole antennas possesses: Two radio-frequency ports, a hemispherical radiation pattern, and an excellent cross-polarization discrimination property. The collected frequency responses of the measured self-interference channels are then digitally processed offline to produce time-domain channel impulse responses. These time-domain responses are presented in form of averaged power-delay profiles. Moreover, we have analyzed statistically the properties of these ten self-interference channels. Time dispersion parameters and their associated values are reported. Furthermore, we presented self-interference channel related parameters such as backscatter maximum peaks and their associated instances of occurrence, and maximum excess delay of the channels.