Doubly-Iterative Decoding of Space Time Turbo Codes With a Large Number of Antennas

We examine the performance of a reduced-complexity doubly iterative decoder for space-time turbo codes on a quasistatic fading channel. The decoder works by using preliminary soft values of the coded symbols, obtained after a limited number of turbo iterations, to reduce the spatial interference from the received signal. Then, new turbo iterations are performed to improve on the quality of the soft values, and so on. Using a number of approximations, we obtain a receiver interface that achieves a good tradeoff between performance and complexity, and allows the use of turbo space-time codes for a large number of transmit and receive antennas.