Performance of Overloaded MIMO-OFDM System with Repetition Code

Hikari MATSUOKA  Yoshihito DOI  Tatsuro YABE  Yukitoshi SANADA  

IEICE TRANSACTIONS on Communications   Vol.E97-B   No.12   pp.2767-2775
Publication Date: 2014/12/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E97.B.2767
Type of Manuscript: PAPER
Category: Wireless Communication Technologies
augmented response,  overloaded MIMO,  QRM-MLD,  

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This paper investigates the performance of an overloaded multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) system with a repetition code. It has been demonstrated that diversity with block coding prevents the performance degradation induced by signal multiplexing. However, the computational complexity of a joint decoding scheme increases exponentially with the number of multiplexed signal streams. Thus, this paper proposes the use of a repetition code in the overloaded MIMO-OFDM system. In addition, QR decomposition with M-algorithm (QRM) maximum likelihood decoding (MLD) is applied to the decoding of the repetition code. QRM-MLD significantly reduces the amount of joint decoding complexity. In addition, virtual antennas are employed in order to increase the throughput that is reduced by the repetition code. It is shown that the proposed scheme reduces the complexity by about 1/48 for 6 signal streams with QPSK modulation while the BER degradation is less than 0.1dB at the BER of 10-3.