Cancellation error statistics in a power-controlled CDMA system using successive interference cancellation

Successive interference cancellation (SIC) is a practical scheme for substantially increasing the capacity of CDMA systems. In order to cancel the received signals of interfering users, estimation of their channel parameters is crucial. To the extent that the channel estimates are inaccurate, residual cancellation interference exists, which is the principal capacity limiting issue in SIC systems. The statistics and probability density function of the residual cancellation error are derived in the presence of fast closed-loop power control. This distribution, which depends directly on the statistics of the power controlled channel, can be accurately modelled with an appropriate Gaussian approximation. The presented results can be directly used in the modelling of future CDMA systems with interference cancellation, in both academia and industry.