A suboptimum iterative decoder for space-time trellis codes

The main problem of space-time trellis codes is constituted by their complexity, which grows exponentially with the number of transmit antennas. To avoid this shortcoming, one can think to a suboptimum decoder in which a simplified metric, together with a preliminary filtering step, is used. In this paper, we develop this idea and give some possible choices for the filter design. These different choices are compared with one another by means of analytical tools and simulations.