Optimal power and polarization for the capacity of polarization division multiple access channels

Polarization diversity has attracted substantial attention in wireless communication system design since polarization is a new domain, which is not as fully utilized as conventional time, frequency, and spatial domains. This paper focuses on the capacity of polarization division multiple access (PDMA) channel to propose an optimal PDMA power allocation scheme that refers to cross-polarization discrimination (XPD). The XPD-based water-filling vessel function is introduced as a main measure of the XPD-aware PDMA power allocation. Further, the relation between the XPD and PDMA channel capacity is described in a mathematical manner. This paper clearly describes the dependence of the optimal PDMA power allocation on the aforementioned XPD-based measure to reach the maximum channel capacity in the power-constrained cellular PDMA system based on orthogonal frequency division multiplexing (OFDM).