Attenuation factors of multistage non-linear parallel interference cancellation with small spread factors

Parallel interference cancellators have been used gradually because of their better performance and lower complexity, for example, in 3G demo systems of Japan. The approaches of regenerating interference and structures of parallel interference cancellators must be adjusted for the sake of the small spread factors of 3G systems. Aiming at interference regeneration of multistage nonlinear PIC with small spread factors for frequency selective Rayleigh fading CDMA systems, we propose a concept of attenuation factors and a novel non-linear PIC scheme based on these factors. We also present expressions of attenuation factors under different optimum cost functions. However, attenuation factors are usually obtained by simulation instead of by theoretical computation or some adaptive algorithms, because of high complexity or convergence problems. At last, we determine the attenuation factors of the proposed scheme through simulations.