Antenna Selection in Polarization Reconfigurable MIMO (PR-MIMO) Communication Systems

Adaptation of a wireless system to the polarization state of the propagation channel can improve reliability and throughput. This paper in particular considers polarization reconfigurable multiple input multiple output (PR-MIMO) systems, where both transmitter and receiver can change the (linear) polarization orientation at each element of their antenna arrays. We first introduce joint polarization pre-post coding to maximize bounds on the capacity and the maximum eigenvalue of the channel matrix. For this we first derive approximate closed form equations of optimal polarization vectors at one link end, and then use iterative joint polarization pre-post coding to pursue joint optimal polarization vectors at both link ends. Next we investigate the combination of PR-MIMO with hybrid antenna selection / maximum ratio transmission (PR-HS/MRT), which can achieve a remarkable improvement of channel capacity and symbol error rate (SER). Further, two novel schemes of element wise and global polarization reconfiguration are presented for PR-HS/MRT. Comprehensive simulation results indicate that the proposed schemes provide 3 to 5 dB SNR gain in PR-MIMO spatial multiplexing and approximately 3 dB SNR gain in PRHS/ MRT, with concomitant improvements of channel capacity and SER.