Performance of channel estimation assisted linear multiuser receivers for downlink CDMA systems with long spreading codes

With availability of spatial/temporal diversity in the downlink of long code CDMA systems, subspace technique has been shown to be able to estimate channel parameters. Based on the estimated channel, we construct three typical linear receivers as ZF, MMSE and RAKE receivers. Due to channel estimation error, those receivers show perturbed performance compared with their optimal counterparts. Their statistical performance is thus analyzed by applying perturbation theory. Those analyses are well supported by numerical results.