Optimal Channel Shortening for MIMO and ISI Channels

We deal with the construction of optimal channel shortening, also known as combined linear Viterbi detection, algorithms for ISI and MIMO channels. In the case of MIMO channel shortening, the tree structure to represent MIMO signals is replaced by a trellis. The optimization is performed from an information theoretical perspective and the achievable information rates of the shortened models are derived and optimized. Closed form expressions for all components of the optimal detector of the class are derived. Furthermore, we show that previously published channel shortening algorithms can be seen as special cases of the derived model.