Joint frequency selective channel estimation and turbo decoding in space time systems

A non-coherent multiple input multiple output (MIMO) coded communication system over a frequency selective (FS) block fading channel is considered. A theoretical limit for the channel estimation error is established via a closed form derivation of the modified Cramer-Rao bound (MCRB) (more precisely, a tight lower bound to it) for the underlying channel model and equi-power signal constellations. Furthermore, it is shown that, for a practical coded MIMO system that employs turbo coding and an appropriate iterative decoding, the resulting mean squared error (MSE) in channel estimation approaches very closely to the derived theoretical limit.