Simplified Maximum Likelihood Detection for FTN Non-Orthogonal FDM System

In this letter, we first apply simplified maximum likelihood detection (MLD) with QR decomposition and M-algorithm (QRM-MLD) to reduce inter-carrier interference (ICI) in a faster-than-Nyquist non-orthogonal frequency division multiplexing (FTN-NOFDM) system. A QRM-MLD algorithm has lower computational complexity than an MLD algorithm owing to the decrease of searched path number. In the experiment, 10-Gb/s FTN-NOFDM with the QRM-MLD algorithm was transmitted over 25-km standard single mode fiber. For 20% bandwidth saving, FTN-NOFDM with the QRM-MLD algorithm can achieve almost the same performance as FTN-NOFDM with the MLD algorithm when the path with minimal metric is not discarded before detecting the last subcarrier, meanwhile the bit error rate of FTN-NOFDM with the QRM-MLD algorithm or the MLD algorithm can achieve 7% forward error correction (FEC) limit, but that with an iterative detection (ID) algorithm only can achieve 20% FEC limit. For reducing ICI, the QRM-MLD algorithm has lower computational complexity but can obtain almost the same performance as the MLD algorithm, and the QRM-MLD algorithm also has much better performance than the ID algorithm.

[1]  Nan Chi,et al.  750Mbit/s visible light communications employing 64QAM-OFDM based on amplitude equalization circuit , 2015, 2015 Optical Fiber Communications Conference and Exhibition (OFC).

[2]  J. Armstrong,et al.  OFDM for Optical Communications , 2009, Journal of Lightwave Technology.

[3]  Hiroyuki Kawai,et al.  Adaptive control of surviving symbol replica candidates in QRM-MLD for OFDM MIMO multiplexing , 2006, IEEE Journal on Selected Areas in Communications.

[4]  K.-D. Kammeyer,et al.  MMSE extension of V-BLAST based on sorted QR decomposition , 2003, 2003 IEEE 58th Vehicular Technology Conference. VTC 2003-Fall (IEEE Cat. No.03CH37484).

[5]  Yuefeng Ji,et al.  A Cost-Effective and Efficient Scheme for Optical OFDM in Short-Range IM/DD Systems , 2014, IEEE Photonics Technology Letters.

[6]  Bane Vasic,et al.  Orthogonal frequency division multiplexing for high-speed optical transmission. , 2006, Optics express.

[7]  Jiang Yue,et al.  A QRD-M/Kalman filter-based detection and channel estimation algorithm for MIMO-OFDM systems , 2005, IEEE Transactions on Wireless Communications.

[8]  Yaojun Qiao,et al.  Faster-than-Nyquist non-orthogonal frequency-division multiplexing based on fractional Hartley transform. , 2016, Optics letters.

[9]  Izzat Darwazeh,et al.  An Improved Fixed Sphere Decoder Employing Soft Decision for the Detection of Non-orthogonal Signals , 2013, IEEE Communications Letters.

[10]  Tao Gui,et al.  Optical SEFDM System; Bandwidth Saving Using Non-Orthogonal Sub-Carriers , 2014, IEEE Photonics Technology Letters.

[11]  Chao Lu,et al.  Efficient MMSE-SQRD-Based MIMO Decoder for SEFDM-Based 2.4-Gb/s-Spectrum-Compressed WDM VLC System , 2016, IEEE Photonics Journal.

[12]  Kyeong Jin Kim,et al.  Joint channel estimation and data detection algorithms for MIMO-OFDM systems , 2002, Conference Record of the Thirty-Sixth Asilomar Conference on Signals, Systems and Computers, 2002..

[13]  M. S. Moreolo,et al.  Novel Power Efficient Optical OFDM Based on Hartley Transform for Intensity-Modulated Direct-Detection Systems , 2010, Journal of Lightwave Technology.

[14]  Qixiang Cheng,et al.  Interleaved single-carrier frequency-division multiplexing for optical interconnects. , 2017, Optics express.

[15]  Neda Cvijetic.  OFDM for next generation optical access networks , 2011 .