Time, space and algebras in information transfer (Q2890481)

This is an overview (in Finnish) of problems of coding for communication in wireless networks (e.g. in mobile communication), where a transmitted signal may be corrupted due to reflection, refraction and scattering and the receiver has to deal simultaneously with several communication partners. To deal with large amounts of information without increasing the communication error, space-time codes have been developed by \textit{V. Tarokh, N. Seshadri} and \textit{A. R. Calderbank} [IEEE Trans. Inf. Theory 44, No. 2, 744--765 (1998; Zbl 0910.94013)]. In the paper the authors consider algebraic grounds for developing space-time codes which are asymptotically optimal in a multiple-antennae (MIMO -- multiple-in-multiple-out) environment in the sense discussed by \textit{L. Zheng} and \textit{D. N. C. Tse} [IEEE Trans. Inf. Theory 49, No. 5, 1073--1096 (2003; Zbl 1063.94531)]. As an example the authors propose a block diagonal code based on cyclic division algebra which in simulations has shown better block error probabilities than other known similar codes.