Parallel interference cancellation (PIC) improvements for CDMAmultiuser receivers using partial cancellation of MAI estimates

摘要

We study the improvement technique for multistage parallelinterference cancellation (PIC) DS-CDMA multiuser receivers, whichcancel only a fraction of the estimated multiple access interference(MAI) at each receiver stage. This technique takes into account the factthat the MAI estimate, especially in the earlier stages, containssubstantial error, and a relatively conservative strategy of using theestimate may lead to better system performance (i.e., lower average biterror rate). We start with simulating the BER performance as a functionof the fraction of cancellation, which shows that the fraction can makea significant difference and a “best” fraction can be farless than one. Then the PIC with partial cancellation and the standardPIC are compared under various near-far effects, channel SNR, and numberof users. The simulations indicate how the partial cancellationtechnique can provide significant improvement over the standardPIC