Multistage Multiuser Detection for Cdma with Space-time Coding

The combination of Turbo codes and space-time block codes is studied for use in CDMA systems. Each user's data are rst encoded by a Turbo code. The Turbo coded data are next sent to a space-time block encoder which employs a BPSK constellation. The space-time en-coder output symbols are transmitted through the fading channel using multiple antennas. A multistage receiver is proposed using non-linear MMSE estimation and a parallel interference cancellation scheme. Simulations show that with reasonable levels of multiple access interference (0:3), near single user performance is achieved. The receiver structure is generalized to decode CDMA signals with space-time convolutional coding and similar performance is observed.