Cross polarization interference canceler for microcellular mobile communication systems

Microcellular system capacity can be doubled by using vertically and horizontally polarized signals. However, the polarization states rotate in the Rayleigh fading propagation environment. Thus, V polarized signals suffer interference from the H polarized signals and vice versa. A novel cross polarization interference canceler (XPIC) for Rayleigh fading channels is proposed and evaluated in the paper. The XPIC improves the bit-error-rate (BER) performance. In a Rayleigh fading channel, the XPIC can reduce the BER by more than 90 percent. Furthermore, in static channels, it can reduce the BER from about 10^-2 to better than 10^-5. V&H polarized signal vectors in the received signal are recovered by obtaining the complex transmission coefficients with the RLS algorithm. XPIC recovers V&H transmitted signals by estimating and eliminating the interference signal. Optimum interference cancellation is achieved if the ratio of the received level of V to the received level H is 1. This technique makes it possible to transmit using both polarization states at the same time in Rayleigh fading channels