Sphere decoder with box optimisation for faster‐than‐Nyquist non‐orthogonal frequency division multiplexing. Issue 4 (1st March 2020)

• Record Type: Journal Article
• Authors: Guo, Mengqi; Zhou, Ji; Lu, Yueming; Qiao, Yaojun
• Is Part Of: IET communications. Volume 14:Issue 4(2020)
• Page Start: 627
• Page End: 634
• Publication Date: 2020-03-01
• Subjects: OFDM modulation -- intersymbol interference -- quadrature amplitude modulation -- error statistics -- decoding -- optical modulation -- quadrature phase shift keying; box optimisation -- faster‐than‐Nyquist nonorthogonal frequency division multiplexing -- potential faster‐than‐Nyquist gain -- inter‐symbol interference -- optimal detector -- FTN single‐carrier binary signal -- Nyquist signal -- bit error rate performance -- Mazo limit -- sphere decoder -- SD -- inter‐carrier interference -- ICI cancellation performance -- transmission rate -- Nyquist rate -- QPSK‐modulated orthogonal frequency division -- 16‐quadrature amplitude modulation‐modulated OFDM -- 16‐QAM‐modulated FTN–NOFDM -- 256‐QAM‐modulated OFDM -- FTN nonorthogonal frequency division multiplexing system; Telecommunication systems -- Periodicals; Speech processing systems -- Periodicals; 621.38205
• DOI: 10.1049/iet-com.2018.5015
• Languages: English
• ISSNs: 1751-8628

Abstract

Abstract : In 1975, J. E. Mazo showed the potential faster‐than‐Nyquist (FTN) gain of the single‐carrier binary signal. If the inter‐symbol interference is eliminated by an optimal detector, FTN single‐carrier binary signal can transmit 24.7% more bits than the Nyquist signal without loss of bit error rate performance, which is known as the Mazo limit. In this study, the authors apply sphere decoder (SD) with box optimisation (BO) to reduce inter‐carrier interference (ICI) in the FTN non‐orthogonal frequency division multiplexing (FTN–NOFDM) system. Compared with the commonly used SD algorithm, SD with BO can achieve the same ICI cancellation performance, and the computational complexity is significantly reduced. When the bandwidth compression factor α is set to 0.802, the transmission rate of FTN–NOFDM is 24.7% faster than the Nyquist rate, and quadrature phase shift keying (QPSK)‐modulated FTN–NOFDM has almost the same performance as QPSK‐modulated orthogonal frequency division multiplexing (OFDM), which agrees well with Mazo limit. In the simulation, the QPSK‐modulated FTN–NOFDM with α = 0.5 outperforms 16‐quadrature amplitude modulation (16‐QAM)‐modulated OFDM by about 1.5 dB, and the 16‐QAM‐modulated FTN–NOFDM with α = 0.67 and 0.5 outperforms 64‐ and 256‐QAM‐modulated OFDM by about 1.5 and 2 dB, respectively.