Capacity limit for faster-than-Nyquist non-orthogonal frequency-division multiplexing signaling

Zhou, Ji; Qiao, Yaojun; Yang, Zhengming; Cheng, Qixiang; Wang, Qi; Guo, Mengqi; Tang, Xizi

doi:10.1038/s41598-017-03571-6

Cited by 33 publications

(25 citation statements)

References 26 publications

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“…32-QAM−128-QAM), requiring more complex DSP and sophisticated narrower linewidth LOs (<100 kHz) compared to common distributed feedback lasers (>1 MHz), our technique may relax requirements on very-high-order QAM signaling. Our technique is also transparent to higher spectral-efficient modulation formats (Fast-OFDM) [44] and non-orthogonal signal modulation techniques [45]. It should be noted that while the required SBS gain of benchmark fiberbased SBS-self-coherent systems is limited by the modulation format order, being less attractive for higher-order QAM signals compared to homodyne schemes, here, the large SBS gain (52 dB) provided by a chalcogenide chip [23] could potentially support up to 64-QAM [1] and above.…”

Section: Resultsmentioning

confidence: 99%

Chip-based Brillouin processing for carrier recovery in self-coherent optical communications

Choudhary

Mägi

Marpaung

et al. 2018

Optica

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Modern fiber-optic coherent communications employ advanced, spectrally-efficient modulation formats that require sophisticated narrow linewidth local oscillators (LOs) and complex digital signal processing (DSP). Self-coherent optical orthogonal frequency-division multiplexing (Self-CO-OFDM) is a modern technology that retrieves the frequency and phase information from the extracted carrier without employing a LO or additional DSP. However, a wide guardband is typically required to easily filter out the optical carrier at the receiver, thus discarding many OFDM middle subcarriers that limits the system data rate. Here, we establish an optical technique for carrier recovery harnessing large-gain stimulated Brillouin scattering (SBS) on a photonic chip for up to 116.82 Gbit⋅s -1 Self-CO-OFDM signals, without requiring a separate LO. The narrow SBS linewidth allows for a record-breaking small carrier guardband of ~265 MHz in Self-CO-OFDM, resulting in higher capacity than benchmark self-coherent multi-carrier schemes. Chip-based SBS-self-coherent technology reveals comparable performance to state-of-the-art coherent optical receivers while relaxing the requirements of the DSP. In contrast to SBS processing on-fiber, our solution provides phase and polarization stability. Our demonstration develops a low-noise and frequency-preserving filter that synchronously regenerates a low-power narrowband optical tone, which could relax the requirements on very-high-order modulation signaling for future communication networks. The proposed hybrid carrier filtering-and-regeneration technique could be useful in long-baseline interferometry for precision optical timing or reconstructing a reference tone for quantum-state measurements.

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Section: Resultsmentioning

confidence: 99%

Chip-based Brillouin processing for carrier recovery in self-coherent optical communications

Choudhary

Mägi

Marpaung

et al. 2018

Optica

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“…The FTN-NOFDM signal is generated when the subcarrier spacing is less than half of the symbol rate per subcarrier [20], [21]. Therefore, under the same spectral efficiency the fractional cosine transformbased (FrCT-based) FTN-NOFDM signal has less ICI than FrFT-based FTN-NOFDM signal [21]. The investigation of this paper is based on FrCT-based FTN-NOFDM signal.…”

Section: Introductionmentioning

confidence: 99%

Sphere decoder with box optimisation for faster‐than‐Nyquist non‐orthogonal frequency division multiplexing

Guo

Zhou²,

et al. 2020

IET Communications

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In 1975, the pioneering work of J. E. Mazo showed the potential faster-than-Nyquist (FTN) gain of single-carrier binary signal. If the inter-symbol interference is eliminated by an optimal detector, the FTN single-carrier binary signal can transmit 24.7% more bits than the Nyquist signal without any loss of bit error rate performance, which is known as the Mazo limit. In this paper, we apply sphere decoder (SD) with box optimization (BO) to reduce inter-carrier interference (ICI) in FTN non-orthogonal frequency division multiplexing (FTN-NOFDM) system. Compared with the conventional SD, SD with BO can achieve the same performance to reduce ICI, but its average number of expanded nodes in search process is significantly decreased especially for high-order modulation format, which can reduce the complexity of the receiver. When the bandwidth compression factor α is set to 0.802, the transmission rate of QPSK-modulated FTN-NOFDM is 24.7% faster than the Nyquist rate, and it has almost the same performance as orthogonal frequency division multiplexing (OFDM), which agrees well with the Mazo limit. The QPSK-modulated FTN-NOFDM with α equal to 0.5 (the spectral efficiency is 4 bit/s/Hz) outperforms 16QAMmodulated OFDM by about 1.5 dB. The 16QAM-modulated FTN-NOFDM with α equal to 0.67 and 0.5 (the spectral efficiency is 6 bit/s/Hz and 8 bit/s/Hz, respectively) outperforms 64QAMmodulated and 256QAM-modulated OFDM by about 1.5 dB and 2 dB, respectively. Therefore, FTN-NOFDM will be a promising modulation scheme for the future bandwidth-limited wireless communications.Index Terms-Box optimization, sphere decoder, faster-than-Nyquist, non-orthogonal frequency division multiplexing, intercarrier interference.

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“…The multistream faster than the Nyquist technique initially proposed in [17] and detailed in [18] is SEFDM's time domain counterpart and has similar spectral efficiency gains with little error performance loss relative to OFDM. The recent report of [19] derives an expression which shows that nonorthogonal multicarrier signals have the potential to achieve higher capacity limits compared to orthogonal signals.…”

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confidence: 99%

“…To ameliorate the effect of such ICI, for uncoded systems, different techniques have been successfully developed, such as sphere decoder [23], fixed sphere decoder [24], pulse shaping [25], and iterative detector [26]. Furthermore, forward error correction (FEC) has been proposed and tested either on its own [27], or as a part of an interference canceller that operates iteratively over the received SEFDM symbols to cancel the interference and to improve the performance of coded systems [19], [28].…”

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confidence: 99%

Experimental Demonstration of Spectrally Efficient Frequency Division Multiplexing Transmissions at E-Band

Ghannam

Nopchinda

Gavell

et al. 2019

IEEE Trans. Microwave Theory Techn.

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This paper presents the design and the experimental demonstration of transmission of spectrally efficient frequency division multiplexing (SEFDM) signals, using a single 5-GHz channel, from 81 to 86 GHz in the E-band frequency allocation. A purpose-built E-band SEFDM experimental demonstrator, consisting of transmitter and receiver GaAs microwave integrated circuits, along with a complete chain of digital signal processing is explained. Solutions are proposed to solve the channel and phase offset estimation and equalization issues, which arise from the well-known intercarrier interference between the SEFDM signal subcarriers. This paper shows the highest transmission rate of 12 Gb/s over a bandwidth varying between 2.67 to 4 GHz depending on the compression level of the SEFDM signals, which results in a spectral efficiency improvement by up to 50%, compared to the conventional orthogonal frequency division multiplexing modulation format.Index Terms-E-band, E-band transceiver, intercarrier interference (ICI), millimeter wave, multicarrier, orthogonal frequency division multiplexing (OFDM), spectral efficiency, spectrally efficient frequency division multiplexing (SEFDM).

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Capacity limit for faster-than-Nyquist non-orthogonal frequency-division multiplexing signaling

Cited by 33 publications

References 26 publications

Chip-based Brillouin processing for carrier recovery in self-coherent optical communications

Chip-based Brillouin processing for carrier recovery in self-coherent optical communications

Sphere decoder with box optimisation for faster‐than‐Nyquist non‐orthogonal frequency division multiplexing

Experimental Demonstration of Spectrally Efficient Frequency Division Multiplexing Transmissions at E-Band

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