No-zero-entry, square, single-symbol ML Decodable STBCs

Space-time block codes based on orthogonal designs (ODs) are used for wireless communications with multiple transmit antennas which can achieve full transmit diversity along single-symbol maximum-likelihood decodability. Single-Symbol Decodable (SSD) codes which are not ODs can be constructed having slightly higher rate than ODs. Elegant constructions of SSD codes using Clifford algebras (Karmakar and Rajan, proceedings of IEEE ISIT, 2006) are known. But these codes, for transmitting antennas more than 4, have large number of zeros in it. Due to the zero entries in the design, the transmitting antenna need to be switched on and off imposing severe hardware constraints. This motivates the construction of SSD codes having no zero entries in the codeword matrices. In this paper we propose a technique for constructing SSD codes having no zero entries in it, having larger rate than the known constructions of the same.