liu.seSearch for publications in DiVA
Change search
ReferencesLink to record
Permanent link

Direct link
MIMO Precoding with X- and Y- Codes
Linköping University, Department of Electrical Engineering, Communication Systems. Linköping University, The Institute of Technology.
Dept. of Electrical and Computer Systems Eng. Monash University, Melbourne, Australia.
Dept. of Electrical and Computer Systems Eng. Monash University, Melbourne, Australia.
Dept. of Electricam and Communication Eng. Indian Institute of Science, Bangalore, India..
2011 (English)In: IEEE Transactions on Information Theory, ISSN 0018-9448, Vol. 57, no 6, 3542-3566 p.Article in journal (Refereed) Published
Abstract [en]

We consider a slow fading nt x nr multiple-input multiple-output (MIMO) system with channel state information (CSI) at both the transmitter and receiver. Since communication in such scenarios is subject to block fading, reception reliability, quantified in terms of the achievable diversity gain, is of importance. A simple and well known precoding scheme is based upon the singular value decomposition (SVD) of the channel matrix, which transforms the MIMO channel into parallel subchannels. Despite having low maximum likelihood decoding (MLD) complexity, this SVD based precoding scheme provides a diversity gain which is limited by the diversity gain of the weakest subchannel. We therefore propose X- and YCodes, which improve the diversity gain of the SVD precoding scheme, by jointly coding information across a pair of subchannels (i.e., pairing subchannels). In particular, subchannels with high diversity gain are paired with those having low diversitygain. A pair of subchannels is jointly encoded using a 2 x 2 real matrix, which is fixed a priori and does not change with each channel realization. For X-Codes, these matrices are 2-dimensional rotation matrices parameterized by a single angle, while for Y-Codes, these matrices are 2-dimensional upper left triangular matrices. Also, since joint coding is performed only across a pair of subchannels, the joint MLD complexity remains low. In particular, the MLD complexity of Y-Codes is even lower than that of X-Codes, and is equivalent to symbol by symbol detection. Moreover, we propose X-, Y-Precoders with the same structure as X-, Y-Codes, but with encoding matrices adapted to each channel realization. With respect to the error probability performance, the optimal encoding matrices for X-, YCodes/ Precoders are derived analytically and numerically. Whencompared to other precoding schemes reported in the literature, it is observed that X-Codes/Precoders perform better in wellconditioned channels, while Y-Codes/Precoders perform better in ill-conditioned channels.

Place, publisher, year, edition, pages
New Jersey, USA: IEEE , 2011. Vol. 57, no 6, 3542-3566 p.
Keyword [en]
MIMO, precoding, diversity, error probability, singular value decomposition, condition number.
National Category
Engineering and Technology
URN: urn:nbn:se:liu:diva-63415DOI: 10.1109/TIT.2011.2133650ISI: 000291003900028OAI: diva2:379507
©2010 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. Saif Khan Mohammed, Emanuele Viterbo, Yi Hong and Ananthanarayanan Chockalingam, MIMO PRECODING WITH X- AND Y- CODES, 2010, accepted: IEEE, Transactions on Information Theory. Available from: 2010-12-17 Created: 2010-12-17 Last updated: 2011-06-10Bibliographically approved

Open Access in DiVA

fulltext(381 kB)513 downloads
File information
File name FULLTEXT01.pdfFile size 381 kBChecksum SHA-512
Type fulltextMimetype application/pdf

Other links

Publisher's full text

Search in DiVA

By author/editor
Mohammed, Saif Khan
By organisation
Communication SystemsThe Institute of Technology
In the same journal
IEEE Transactions on Information Theory
Engineering and Technology

Search outside of DiVA

GoogleGoogle Scholar
Total: 513 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 602 hits
ReferencesLink to record
Permanent link

Direct link