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Keying

About: Keying is a research topic. Over the lifetime, 6598 publications have been published within this topic receiving 82943 citations.


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Journal ArticleDOI
TL;DR: In this paper, the performance monitoring of optical signal-to-noise ratio, chromatic dispersion, and polarization-mode dispersion in return-tozero differential quadrature phase-shift keying signals is demonstrated using asynchronous delay-tap sampling and pattern recognition algorithms.
Abstract: Feature Issue on Transmission in Optically Transparent Core NetworksThe emerging transparent optical networks, employing spectrally efficient modulation formats, require new methods for supervision of signal quality in order to maintain control over the transmission in all-optical domains. Optical performance monitoring of optical signal-to-noise ratio, chromatic dispersion, and polarization-mode dispersion in return-to-zero differential quadrature phase-shift keying signals is demonstrated using asynchronous delay-tap sampling and pattern recognition algorithms. Precise estimation of parameters over a broad range of impairment levels and good degradation isolation is shown by means of numerical simulation.

37 citations

Journal ArticleDOI
TL;DR: It is shown that the proposed method significantly outperforms the uncoded systems for various receiver structures such as a correlator with and without hard-limiter and chip-level detector and in the presence of different values of dark current.
Abstract: In this paper, we consider using practical low-rate error correcting codes in fiber-optic code division multiple-access (CDMA) communication systems. To this end, a different method of low-rate channel coding is proposed. As opposed to the conventional coding schemes, this method does not require any further bandwidth expansion for error correction in fiber-optic CDMA communication systems. The low-rate channel codes that are used for demonstrating the capabilities of the proposed method are super-orthogonal codes. These codes are near optimal and have a relatively low complexity. We evaluate the upper bounds on the bit-error probability of the proposed coded fiber-optic CDMA system assuming both on-off keying and binary pulse position modulation schemes. It is shown that the proposed method significantly outperforms the uncoded systems for various receiver structures such as a correlator with and without hard-limiter and chip-level detector. Furthermore, the performance of the proposed coded fiber-optic CDMA system is also evaluated in the presence of different values of dark current.

37 citations

Journal ArticleDOI
TL;DR: A survey and tutorial is provided on the subject of multiple-input-multiple-output (MIMO) multicarrier (MC) systems relying on the space-time shift keying (STSK) concept, followed by the design of STSK systems in the context of MC modulation-based transmissions over dispersive wireless channels.
Abstract: A survey and tutorial is provided on the subject of multiple-input–multiple-output (MIMO) multicarrier (MC) systems relying on the space–time shift keying (STSK) concept. We commence with a brief review of the family of MIMO systems, which is followed by the design of STSK systems in the context of MC modulation-based transmissions over dispersive wireless channels. Specifically, the STSK scheme is amalgamated with orthogonal frequency-division multiplexing, MC code-division multiple access, orthogonal frequency-division multiple access (OFDMA), and single-carrier frequency-division multiple access. We also provide a rudimentary introduction to MC differential STSK employing both conventional differential detection and multiple-symbol differential sphere decoding for the sake of dispensing with channel estimation. We conclude with the design recipes of coherent versus noncoherent MC STSK schemes, complemented by a range of future research ideas.

37 citations

01 Jan 2012
TL;DR: It is demonstrated that in the presence of severe nonlinear distortions, it may become beneficial to sacrifice a constellation point or an entire constellation ring to reduce the average SEP.
Abstract: We study the design of amplitude phase-shift keying (APSK) constellations for a coherent fiber-optical communication system where nonlinear phase noise (NLPN) is the main system impairment. APSK constellations can be regarded as a union of phase-shift keying (PSK) signal sets with different amplitude levels. A practical two-stage (TS) detection scheme is analyzed, which performs close to optimal detection for high enough input power. We optimize APSK constellations with 4, 8, and 16 points in terms of symbol error probability (SEP) under TS detection for several combinations of input power and fiber length. For 16 points, performance gains of 3.2 dB can be achieved at a SEP of 10-2 compared to 16-QAM by choosing an optimized APSK constellation. We also demonstrate that in the presence of severe nonlinear distortions, it may become beneficial to sacrifice a constellation point or an entire constellation ring to reduce the average SEP. Finally, we discuss the problem of selecting a good binary labeling for the found constellations.

37 citations

Journal ArticleDOI
TL;DR: This labeling scheme allows the use of a deeply saturated semiconductor optical amplifier to perform polarization-insensitive label erasure and receiver sensitivity of /spl sim/-36 dBm and penalty-free transmission over 80-km standard single-mode fiber are achieved for both the payload and the label.
Abstract: We demonstrate an optically labeled signal based on return-to-zero differential phase-shift keying for payload at 10-Gb/s and amplitude-shift keying for label at 622-Mb/s. Receiver sensitivity of /spl sim/-36 dBm and penalty-free transmission over 80-km standard single-mode fiber are achieved for both the payload (with dispersion compensation) and the label. This labeling scheme allows the use of a deeply saturated semiconductor optical amplifier to perform polarization-insensitive label erasure. Label swapping is demonstrated with moderate penalty.

37 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023137
2022286
2021170
2020238
2019301
2018291