Cross polarization interference canceler for microcellular mobile communication systems
M. Takahashi, H. Takahashi, Takaaki Tanaka · 2002
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/sup -2/ to better than 10/sup -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.