Multi-Class Coded Layered Asymmetrically Clipped Optical OFDM

Zhang, Xiaoyu; Babar, Zunaira; Zhang, Rong; Chen, Sheng; Hanzo, Lajos

doi:10.1109/tcomm.2018.2869821

Cited by 23 publications

(27 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Errors in Layer n may not necessarily propagate to Layer (n + 1), because the error vectors are small, as they are residues of the un-cancelled clipping distortion and their power is distributed across many subcarriers. Inter-layer error correction reduces error propagation still further, as proposed by Hanzo's group [41,42] and also disclosed by Song's PhD [43].…”

Section: (A) Enhanced Unipolar Orthogonal Frequency Division Multiplementioning

confidence: 99%

Spectrally efficient optical orthogonal frequency division multiplexing

Lowery

2020

Phil. Trans. R. Soc. A.

View full text Add to dashboard Cite

This paper charts the development of spectrally efficient forms of optical orthogonal frequency division multiplexing (OFDM) that are suited for intensity-modulated direct detection systems, such as wireless optical communications. The journey begins with systems using a DC-bias to ensure that no parts of the signal that modulates the optical source are negative in value, as negative optical intensity is unphysical. As the DC-part of the optical signal carries no information, it is wasteful in energy; thus asymmetrically clipped optical OFDM was developed, removing any negative-going peaks below the mean. Unfortunately, the clipping causes second-order distortion and intermodulation, so some subcarriers appear to be unusable, halving spectral efficiency; this is similar for unipolar and flipped optical OFDM. Thus, a considerable effort has been made to regain spectral efficiency, using layered techniques where the clipping distortion is mostly cancelled at the receiver, from a knowledge of one unpolluted layer, enabling one or more extra ‘layers/paths/depths’ to be received on the previously unusable subcarriers. Importantly, for a given optical power and high-order modulation, layered methods offer the best spectral efficiencies and need the lowest signal-to-noise ratios, especially if diversity combining is used. Thus, they could be important for high-bandwidth optical fibre systems. Efficient methods of generating all layers simultaneously, using fast Fourier transforms with their partial calculations extracted, are discussed, as are experimental demonstrations in both wireless and short-haul communications links. A musical analogy is also provided, which may point to how orchestral and rock music is deciphered in the brain. This article is part of the theme issue ‘Optical wireless communication’.

show abstract

Section: (A) Enhanced Unipolar Orthogonal Frequency Division Multiplementioning

confidence: 99%

Spectrally efficient optical orthogonal frequency division multiplexing

Lowery

2020

Phil. Trans. R. Soc. A.

View full text Add to dashboard Cite

show abstract

“…1. In the multi-class coded LACO-OFDM of [10], each layer encodes a different information stream. By contrast, the proposed multi-layered coded LACO-OFDM encodes the same information in each layer.…”

Section: A Transmittermentioning

confidence: 99%

“…By contrast, the proposed multi-layered coded LACO-OFDM encodes the same information in each layer. Hence, while the multi-class coded LACO-OFDM of [10] layer, the multi-layered coded LACO-OFDM of Fig. 1 spreads redundancy across the layers in the spirit of invoking iterations between the LACO-OFDM layers.…”

Section: A Transmittermentioning

confidence: 99%

“…Zhang et al [10] were the first to integrate Forward Error Correction (FEC) codes into the LACO-OFDM system. It was shown in [10] that, for the sake of reducing ILI in a coded LACO-OFDM system, it is more beneficial to embed FEC codes in each layer rather than using a single FEC code serially concatenated with the LACO-OFDM module. The resulting coding scheme of [10] is named 'multi-class coded LACO-OFDM'.…”

Section: Introductionmentioning

confidence: 99%

“…It was shown in [10] that, for the sake of reducing ILI in a coded LACO-OFDM system, it is more beneficial to embed FEC codes in each layer rather than using a single FEC code serially concatenated with the LACO-OFDM module. The resulting coding scheme of [10] is named 'multi-class coded LACO-OFDM'. Analogous to the uncoded LACO-OFDM system, the higher layers of a multi-class coded LACO-OFDM scheme exhibit a worse BER than the lower layers.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Near-Capacity Multilayered Code Design for LACO-OFDM-Aided Optical Wireless Systems

Babar

Zhang

Botsinis

et al. 2019

IEEE Trans. Veh. Technol.

Self Cite

View full text Add to dashboard Cite

In this letter, we conceive a multi-layered coding scheme for the recently proposed Layered Asymmetrically Clipped Optical Orthogonal Frequency Division Multiplexing (LACO-OFDM) system, which exploits its layered structure for protecting the information bits transmitted in the base layer. Explicitly, we intrinsically integrate error correction into the layered structure of the LACO-OFDM system and invoke soft iterative decoding between the layers at the receiver. Our system operates within 2 dB of the capacity limit at a BER of 10 −4 .

show abstract

Coherent and Non-Coherent Multilayer Index Modulation

Gopi¹,

Kalyani²,

Hanzo³

2019

IEEE Access

View full text Add to dashboard Cite

Index modulation assisted OFDM (OFDM-IM) has become a popular technique in wireless communications. In this paper, we proposes a novel multilayer framework for OFDM-IM. Being quite generic in its nature, the framework can be amalgamated with most of the OFDM-IM variants. For coherent OFDM-IM, we propose three different schemes; 1) multilayer index modulation (MIM); 2) dual mode MIM; and 3) compressive sampling aided MIM. The schemes strikes a compelling tradeoff between the BER, energy efficiency and throughput. Finally, we extend this multilayer framework to non-coherent index modulation, where the structure provides an improved BER performance compared to its single layer counterpart, albeit this is achieved at the cost of reduced energy efficiency. The performance analysis of the proposed scheme is confirmed by our simulation results.

show abstract

Multi-Class Coded Layered Asymmetrically Clipped Optical OFDM

Cited by 23 publications

References 35 publications

Spectrally efficient optical orthogonal frequency division multiplexing

Spectrally efficient optical orthogonal frequency division multiplexing

Near-Capacity Multilayered Code Design for LACO-OFDM-Aided Optical Wireless Systems

Coherent and Non-Coherent Multilayer Index Modulation

Contact Info

Product

Resources

About