Parallel interference cancellation with commutation signaling

This paper considers the SIC-subtractive interference cancellation and PIC-parallel interference cancellation with and without the ISI cancellation system-commutation signaling (CS), in a deep Rayleigh fading environment, time and frequency selective, assuming the spreading sequences and the features of the channels of the several interfering users is known. It is shown that SIC and PIC lead to better performance when the CS technique is used together, once these systems subtract the MAI estimated for each user. These estimates improve when the ISI is cancelled, since the MAI estimated depends upon the estimate of the transmitted symbols by each interfering user. A blind detection (without knowledge of spreading sequences nor the features of the channels of the interfering users) with a noise whitening matched filter (NWMF) that combats the MAI through the whitening of the interfering power spectrum (following the single-user philosophy) is also developed.