Maximum Rate of Unitary-Weight, Single-Symbol Decodable STBCs

Karmakar, Sanjay and Srinath, Pavan K and Rajan, Sundar B (2011) Maximum Rate of Unitary-Weight, Single-Symbol Decodable STBCs. In: IEEE Transactions on Information Theory, 57 (12). pp. 7972-7981.

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Abstract

It is well known that the space-time block codes (STBCs) from complex orthogonal designs (CODs) are single-symbol decodable/symbol-by-symbol decodable (SSD). The weight matrices of the square CODs are all unitary and obtainable from the unitary matrix representations of Clifford Algebras when the number of transmit antennas n is a power of 2. The rate of the square CODs for n = 2(a) has been shown to be a+1/2(a) complex symbols per channel use. However, SSD codes having unitary-weight matrices need not be CODs, an example being the minimum-decoding-complexity STBCs from quasi-orthogonal designs. In this paper, an achievable upper bound on the rate of any unitary-weight SSD code is derived to be a/2(a)-1 complex symbols per channel use for 2(a) antennas, and this upper bound is larger than that of the CODs. By way of code construction, the interrelationship between the weight matrices of unitary-weight SSD codes is studied. Also, the coding gain of all unitary-weight SSD codes is proved to be the same for QAM constellations and conditions that are necessary for unitary-weight SSD codes to achieve full transmit diversity and optimum coding gain are presented.

Item Type:	Journal Article
Publication:	IEEE Transactions on Information Theory
Publisher:	IEEE
Additional Information:	Copyright 2011 IEEE. Personal use of this material is permitted.However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.
Keywords:	Anticommuting matrices;complex orthogonal designs;minimum-decoding-complexity codes;quasi-orthogonal designs; space-time block codes
Department/Centre:	Division of Electrical Sciences > Electrical Communication Engineering
Date Deposited:	03 Jan 2012 12:30
Last Modified:	03 Jan 2012 12:30
URI:	http://eprints.iisc.ac.in/id/eprint/42967

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