Adaptive Subspace Iterative Information Measure Directed Synchronization in MIMO Channel

The paper addresses the problem of iterative soft-information measure supported synchronization. The authors use a subspace based model for the arbitrarily time-variant MIMO channel. The channel subspace can have arbitrary dimension allowing to model also a fast time-variant channel. The equivalence between Expectation-Maximization based iterative synchronizer and weighted Least Squares problem is demonstrated to hold for general MIMO system. They introduce the idea of adaptive subspace control during the iterative synchronization iterations using the order recursive solver.