Information Guided Precoding for OFDM

Qiang Li, Miaowen Wen, H. Vincent Poor, Fangjiong Chen

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


In conventional orthogonal frequency division multiplexing with index modulation (OFDM-IM), the M-Ary modulated symbols are transmitted on a subset of subcarriers under the guidance of information bits. In this paper, a novel information guided precoding technique, called precoding aided (P-) OFDM-IM, is proposed to improve the spectral efficiency (SE) of OFDM-IM. In P-OFDM-IM, the information bits are jointly conveyed through the conventional M-Ary modulated symbols and the indices of precoding matrices and vectors. The P-OFDM-IM principle is embodied in two different implementations, P-OFDM-IM-I and P-OFDM-IM-II. Specifically, P-OFDM-IM-I divides all subcarriers into L groups and modulates them using $L distinguishable constellations. P-OFDM-IM-II partitions the set of all subcarriers into L overlapping layers and performs IM layer by layer, where distinguishable constellations are employed across layers. A practical precoding strategy is designed for P-OFDM-IM under the phase shift keying/quadrature amplitude modulation constraint. A low-complexity log-likelihood ratio detector is proposed to ease the computational burden on the receiver. To evaluate the performance of P-OFDM-IM analytically, an upper bound on the bit error rate and the achievable rate is studied. Computer simulation results show that P-OFDM-IM-I outperforms the existing OFDM-IM-related schemes at high SE, while P-OFDM-IM-II performs the best at low SE.

Original languageEnglish (US)
Article number8006223
Pages (from-to)19644-19656
Number of pages13
JournalIEEE Access
StatePublished - Aug 9 2017

All Science Journal Classification (ASJC) codes

  • General Computer Science
  • General Materials Science
  • General Engineering


  • OFDM
  • index modulation
  • log-likelihood ratio (LLR)
  • maximum-likelihood (ML)
  • precoding


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