An Iterative MIMO Receiver Employing Virtual Channels with a Turbo Decoder for OFDM Wireless Systems

Akihito TAYA  Satoshi DENNO  Koji YAMAMOTO  Masahiro MORIKURA  Daisuke UMEHARA  Hidekazu MURATA  Susumu YOSHIDA  

IEICE TRANSACTIONS on Communications   Vol.E98-B   No.5   pp.878-889
Publication Date: 2015/05/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E98.B.878
Type of Manuscript: PAPER
Category: Wireless Communication Technologies
multiple-input multiple-output,  virtual channel,  soft-input soft-output,  log likelihood ratio,  iterative scheme,  

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This paper proposes a novel iterative multiple-input multiple-output (MIMO) receiver for orthogonal frequency division multiplexing (OFDM) systems, named as an “iterative MIMO receiver employing virtual channels with a Turbo decoder.” The proposed MIMO receiver comprises a MIMO detector with virtual channel detection and a Turbo decoder, between which signals are exchanged iteratively. This paper proposes a semi hard input soft output (SHISO) iterative decoding for the iterative MIMO receiver that achieves better performance than a soft input soft output (SISO) iterative decoding. Moreover, this paper proposes a new criterion for the MIMO detector to select the most likely virtual channel. The performance of the proposed receiver is verified in a 6×2 MIMO-OFDM system by computer simulation. The proposed receiver achieves better performance than the SISO MAP iterative receiver by 1.5dB at the bit error rate (BER) of 10-4, by optimizing the number of the Turbo iteration per the SHISO iteration. Moreover, the proposed detection criterion enables the proposed receiver to achieve a gain of 3.0dB at the BER of 10-5, compared with the SISO MAP iterative receiver with the Turbo decoder.