A multiuser detection method for overlay CDMA systems

To provide new and/or higher rate wireless services with limited bandwidth resources, frequency overlay has been proposed to host heterogeneous traffic in common band, where one CDMA system is involved due to its noise-like nature. In the paper, we address multiuser detection problem for overlay scenarios where there exist multiple CDMA systems. We propose a linear parallel interference cancellation (PIC) structure where interference due to overlaid systems is captured and subtracted by means of its subspace. Simulation results validated our solution and show that the proposed receiver has better performance in various aspects than the conventional MMSE receiver.