Blind separation of space-time block coded signals via the analytic constant modulus algorithm

Previous work has shown how the special structure of linear space-time block codes can be exploited for blind equalization or direct symbol estimation in MIMO wireless systems. In this paper it is demonstrated that improved performance can be obtained by combining the information provided by the structure of the code together with a priori knowledge that the data symbols are constant modulus. A variation of the analytic constant modulus algorithm of van der Veen (see Proc. ICASSP, Salt Lake City, UT, 2001, vol. V, p.2773-76) is used to exploit the full spatial and temporal diversity of the codes in a single step, rather than via ad hoc post-processing. Simulations indicate that the algorithm performs particularly well in situations with very few data samples.