Iterative channel estimation in the multiuser pilot-assisted CDMA system

A novel joint channel estimation and partial parallel interference cancellation (JCPPIC) receiver is proposed in the up-link pilot-assisted CDMA (code division multiple access system), where the transmitted pilot symbols are followed by information data symbols in each time slot of each user. In the JCPPIC receiver, the joint iterative structure is utilized to deal with the inaccurate reception problem in the pilot part caused by multiple access interference (MAI). In the proposed iterative scheme, not only the soft-out decision but also the channel estimations are updated in each iteration by partially combining with the former stage´s counterparts. In addition, an adaptive piecewise polynomial interpolation (APPI) is applied into the receiver as the estimation method. Simulation results show that both JCPPIC and APPI can outperform their contrast methods.