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 first 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 encoder output symbols are transmitted through the fading channel using multiple antennas. A multistage receiver is proposed using nonlinear MMSE estimation and a parallel interference cancellation scheme. Simulations show that with reasonable levels of multiple access interference (p/spl les/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.