A novel power-efficient scheme asymmetrically and symmetrically clipping optical (ASCO)-OFDM for IM/DD optical systems

Wu, Nan; Bar-Ness, Y.

doi:10.1186/1687-6180-2015-3

Cited by 29 publications

(38 citation statements)

References 15 publications

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“…Schemes [13], here we use an alternative, but equivalent description for the ASCO-OFDM. *** It stands for several essentially equivalent schemes including the spectrally and energy efficient OFDM (SEE-OFDM) [14], [15], the layered ACO-OFDM (LACO-OFDM) [16], and the eACO-OFDM [17].…”

Section: Multi-componentmentioning

confidence: 99%

“…Proof: We combine the proofs for these two schemes together since they share the same approach. [12], [13], and therefore, the information rates of the ACO-OFDM components can be obtained by Theorem 2 directly. Since the total transmit power is the sum of the powers of both components, we let the power of the ACO-OFDM component be (1 − λ)E, and the information rate of the ACO-OFDM component with ICG codebook ensemble and nearest neighbor decoding is thus…”

Section: Double-component Schemesmentioning

confidence: 99%

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A Comparative Study of Unipolar OFDM Schemes in Gaussian Optical Intensity Channel

Zhou

Zhang

2018

IEEE Trans. Commun.

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We study the information rates of unipolar orthogonal frequency division multiplexing (OFDM) in discrete-time optical intensity channels (OIC) with Gaussian noise under average optical power constraint. Several single-, double-, and multicomponent unipolar OFDM schemes are considered under the assumption that independent and identically distributed (i.i.d.) Gaussian or complex Gaussian codebook ensemble and nearest neighbor decoding (minimum Euclidean distance decoding) are used. We obtain an array of information rate result. These results validate existing signal-to-noise-and-distortion-ratio (SNDR) based rate analysis, establish the equivalence of information rates of certain schemes, and demonstrate the evident benefits of using component-multiplexing at high signal-to-noise-ratio (SNR). For double-and multi-component schemes, the component power allocation strategies that maximize the information rates are investigated. In particular, by utilizing a power allocation strategy, we prove that several multi-component schemes approach the high SNR capacity of the discrete-time Gaussian OIC under average power constraint to within 0.07 bits.Index Terms-Channel capacity, information rate, intensity modulation and direct detection (IM/DD), optical wireless communications (OWC), orthogonal frequency division multiplexing (OFDM).

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Section: Multi-componentmentioning

confidence: 99%

Section: Double-component Schemesmentioning

confidence: 99%

A Comparative Study of Unipolar OFDM Schemes in Gaussian Optical Intensity Channel

Zhou

Zhang

2018

IEEE Trans. Commun.

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“…Orthogonal frequency division multiplex (OFDM) has been applied in digital television broadcasting standards, wireless/wired communications and optical communications [1][2][3]. It has been adopted as the physical layer modulation scheme in 4G wireless communications and is visioned as a candidate for 5G [4].…”

Section: Introductionmentioning

confidence: 99%

Delay-tolerant equalization for OFDM and other block-based systems

Zeng

2015

2015 10th International Conference on Information, Communications and Signal Processing (ICICS)

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Orthogonal frequency division multiplex (OFDM) and other block-based systems have been widely used in wireless and wired communications. To combat frequency selectivity of channel, such systems usually adds a cyclic prefix (CP) or zeropadding (ZP) into every block. In conventional equalization, the receiver discards the CP first and then implements the fast Fourier transform (FFT) and divides the output by the frequency domain channel. In practice the received signals usually has timing errors, which makes the conventional equalization unreliable. In this paper, we propose a new equalization method called "delay-tolerant equalization", which either discarding the CP or discarding the last Ng symbols of every block, where Ng is the length of the CP. Furthermore, practical "tuning processes" are proposed that use the existing preambles. Theoretic analysis and simulation show that the new method is much better than the conventional method when random time synchronization error exists.

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“…Other optical OFDM schemes have been proposed to over-come the drawbacks of DCO-OFDM and ACO-OFDM, such as asymmetrically clipped DC-biased optical OFDM (ADO-OFDM) [18], [19], hybrid asymmetrically clipped optical OFDM (HACO-OFDM) [14], asymmetrically and symmetrically clipped optical OFDM (ASCO-OFDM) [20], etc. In ADO-OFDM, ACO-OFDM symbols are modulated on the odd subcarriers while DCO-OFDM symbols are modulated on the even subcarriers.…”

Section: Introductionmentioning

confidence: 99%

“…Note that the real part of the even subcarriers is wasted. As for ASCO-OFDM, ACO-OFDM symbols are modulated on the odd subcarriers while symmetrically clipping optical OFDM (SCO-OFDM) symbols are modulated on the even subcarriers of two adjacent SCO-OFDM blocks [20]. Since the information carried by the two adjacent SCO-OFDM blocks is from the same OFDM block, the half of the even subcarriers are wasted.…”

Section: Introductionmentioning

confidence: 99%

Asymmetrically Clipped Absolute Value Optical OFDM for Intensity-Modulated Direct-Detection Systems

Bai

Wang

Hanzo

2017

J. Lightwave Technol.

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Abstract-Orthogonal frequency division multiplexing (OFD-M) is attracting increasing attention in optical communication systems thanks to the inherent benefits such as high spectral efficiency and resistance to frequency-selective channels. In this paper, a novel energy and spectrally efficient scheme called asymmetrically clipped absolute value optical OFDM (AAO-OFDM) is proposed for intensity-modulated direct-detection (IM/DD) systems. In AAO-OFDM, absolute value optical OFDM (AVO-OFDM) signals on the even subcarriers and asymmetrically clipped optical OFDM (ACO-OFDM) signals on the odd subcarriers are combined for simultaneous transmission, which employs all the subcarriers requiring no DC biases. For AVO-OFDM scheme, the frequency symbols are firstly modulated on the even subcarriers, which are then fed into an inverse fast Fourier transform block. Afterwards, the absolute values of the bipolar time-domain signals are taken to guarantee nonnegativity, while their signs are mapped to the complex-valued symbols and modulated on the odd subcarriers. Since there remain unused odd subcarriers, other useful symbols can be modulated on them, which leads to the conventional ACO-OFDM scheme. At the receiver, the ACO-OFDM symbols on the odd subcarriers are demodulated firstly, which are reconstructed and removed from the received signals. Afterwards, the remaining signals are utilized to detect the AVO-OFDM symbols with the aid of the demodulated sign symbols on the odd subcarriers. Theoretical analysis and simulation results show that AAO-OFDM has lower peak-to-average power ratio than other optical OFDM schemes, which makes it less sensitive to the nonlinearity of the optical devices. Furthermore, it achieves better bit error rate performance compared to its counterparts for the same spectral efficiency.Index Terms-Intensity modulation with direct detection, orthogonal frequency division multiplexing, energy efficiency, spectral efficiency.

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A novel power-efficient scheme asymmetrically and symmetrically clipping optical (ASCO)-OFDM for IM/DD optical systems

Cited by 29 publications

References 15 publications

A Comparative Study of Unipolar OFDM Schemes in Gaussian Optical Intensity Channel

A Comparative Study of Unipolar OFDM Schemes in Gaussian Optical Intensity Channel

Delay-tolerant equalization for OFDM and other block-based systems

Asymmetrically Clipped Absolute Value Optical OFDM for Intensity-Modulated Direct-Detection Systems

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