DocumentCode :
1166996
Title :
Unitary Nongroup STBC From Cyclic Algebras
Author :
Abarbanel, Joseph ; Averbuch, Amir ; Rosset, Shmuel ; Zlotnick, Joseph
Author_Institution :
Sch. of Math. Sci., Tel-Aviv Univ.
Volume :
52
Issue :
9
fYear :
2006
Firstpage :
3903
Lastpage :
3912
Abstract :
Space-time block codes (STBCs) are designed for multiple-input-multiple-output (MIMO) channels. In order to avoid errors, single-input-single-output (SISO) fading channels require long coding blocks and interleavers that result in high delays. If one wishes to increase the data rate it is necessary to take advantage of space diversity. Early STBC, that where developed by Alamouti for known channels and by Tarokh for unknown channels, have been proven to increase the performance of channels characterized by Rayleigh fading. Codes that are based on division algebras have by definition nonzero diversity and therefore are suitable for STBC in order to achieve high rates at low symbol-to-noise ratio (SNR). This work presents new high-diversity group-based STBCs with improved performance both in known and unknown channels. We describe two new sets of codes for multiple antenna communication. The first set is a set of "superquaternions" and improves considerably on the Alamouti codes. It is based on the mathematical fact that "normalized" integral quaternions are very well distributed over the unit sphere in four-dimensional (4-D) Euclidean space. The second set of codes gives arrays of 3times3 unitary matrices with full diversity. Here the idea is to use cosets of finite subgroups of division algebras that are nine-dimensional (9-D) over their center, which is a finite cyclotomic extension of the field of rational numbers. It is shown that these codes outperform Alamouti and G mr
Keywords :
MIMO systems; Rayleigh channels; algebraic codes; channel coding; cyclic codes; diversity reception; group codes; interleaved codes; matrix algebra; space-time codes; Alamouti code; MIMO channel; Rayleigh fading; SISO fading channel; cyclic algebra; four-dimensional Euclidean space; interleaver; multiple antenna communication; multiple-input-multiple-output system; normalized integral quaternion; single-input-single-output system; space diversity; space-time block code; superquaternion; unitary matrix; unitary nongroup STBC; Algebra; Block codes; Delay; Fading; Integral equations; MIMO; Quaternions; Rayleigh channels; Transmitting antennas; Wireless communication; Codes for; cosets of finite subgroups of division algebras; integral quaternions; multiple-input multiple-output (MIMO); space–time block code (STBC); superquaternions;
fLanguage :
English
Journal_Title :
Information Theory, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-9448
Type :
jour
DOI :
10.1109/TIT.2006.880022
Filename :
1683916
Link To Document :
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