Combined Trellis Precoding and Error Correcting Codes in Multi-User MIMO-OFDM Systems

Tsuguhide AOKI  Hideki OCHIAI  Ryuji KOHNO  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E93-A   No.12   pp.2663-2671
Publication Date: 2010/12/01
Online ISSN: 1745-1337
DOI: 10.1587/transfun.E93.A.2663
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on Wideband Systems)
nonlinear precoding,  multi-user MIMO,  trellis precoding,  trellis shaping,  OFDM,  

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A major drawback with linear precoding in a downlink multi-user MIMO system is the increase in the transmit power when a channel is correlated. On the other hand, nonlinear trellis precoding in downlink multi-user MIMO systems is capable of minimizing the transmit power by adding a shaping sequence to the original transmit sequence. However, conventional trellis precoding cannot be directly applied to existing bit-interleaved coded MIMO-OFDM systems since the trellis precoding and error correcting codes should be designed separately. In this paper, we proposed to embed trellis precoding into the error correcting codes that are used in the original multi-user MIMO-OFDM system employing linear precoding. Major advantage of this approach is that the receiving procedure at user terminals designed for the original system need not be changed up to the error correcting decoder to support our trellis precoding. Computer simulations show that the proposed trellis precoding provides improvements of 2 dB and 2.5 dB in 22 and 33 MIMO configurations, respectively.