Capacity Maximization with Polarization-Agile Antennas in the MIMO Communication System

Abstract

Polarization diversity is an important candidate for improving the channel capacity in multiple-input multiple-output (MIMO) communication systems. The use of polarization-agile antennas enables to reap important benefits of polarization diversity without the need for additional up/down-conversion chains and their associated cost and energy consumption. In this paper we propose a novel scheme of polarization pre-post coding based on the theoretical (approximate) closed-form derivation of optimal transmit/receive polarization vectors to maximize channel capacity when polarization agility is available only at one link end. We use those as basis for an iterative joint polarization prepost coding for polarization agility at both link ends. Simulations validate that the obtained capacity is in a close agreement with that obtained by exhaustive numerical search for optimal transmit/receive polarization orientation. Utilizing our scheme of joint polarization pre-post coding improves system performance by 3 dB to 5 dB in terms of the SNR.

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

“…Three terms in each β i for i ∈ {1, 2, 3, 4} are independent of each other. Thus, the variance of the real and imaginary parts in β i is 1 2 × 1 2 × 1 2 = 1 8 ; consequently, h eff ij has unit variance as described in detail in Appendix A. It is noteworthy that the mean and variance of reconfigurable antennas with random channel polarization are the same as those of conventional channels without polarization reconfigurable antenna elements.…”

“…It is worth emphasizing that each element of H eff is affected by the Tx-and Rx-polarization as implied in (1). Hence, the polarization vectors at polarization reconfigurable antenna elements impact constructively or destructively the MIMO channel capacity itself, even though SVD-based precoding/postcoding reaches the MIMO channel capacity for the given full CSIR/CSIT.…”

“…However, it can also be an advantage, since the different polarizations offer degrees of freedom that can be exploited for diversity and/or spatial multiplexing. Therefore, numerous investigations have been made into use of the polarization domain [1]- [15]. It has been demonstrated that utilizing the polarization domain may increase channel capacity and spectral efficiency and improve symbol error rate (SER) [1], [16]- [20].…”

“…Therefore, numerous investigations have been made into use of the polarization domain [1]- [15]. It has been demonstrated that utilizing the polarization domain may increase channel capacity and spectral efficiency and improve symbol error rate (SER) [1], [16]- [20]. For this reason, impact of polarization on the wireless communication systems has Paul S. Oh and Sean S. Kwon are co-first authors with the equal contribution.…”

“…been regarded as a promising research topic [1], [2], [5], [21]- [25]. Most of the above papers assume that the Tx and Rx have co-located dual-polarized antennas, such that two antenna ports are available for each antenna element at a distinct spatial location.…”