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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.


Papers
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Journal ArticleDOI
Lee-Fang Wei1
TL;DR: Three categories of coded M-DPSK (M-ary differential phase-shift keying) schemes with built-in time diversity are constructed under a constraint on the interleaving delay.
Abstract: Good coded modulation for fading channels requires built-in time diversity. Under a constraint on the interleaving delay, the authors construct and compare three categories of coded M-DPSK (M-ary differential phase-shift keying) schemes with 4 >

54 citations

Journal ArticleDOI
TL;DR: It is shown that the proposed coded scheme under modulated
Abstract: This work offers both analog and digital tag modulation schemes and respective receiver designs, for ultra -low power, high performance, ambient backscatter communications. All proposed techniques are based on simple, but careful, switching frequency control at the tag, allowing for the easy frequency-domain multiple access. First, a digital modulation scheme is offered, namely pseudo-frequency shift keying, assuming illumination from constant envelope-modulated signals and a fully coherent detector is derived along with closed-form probability of error. A second digital modulation scheme is also offered, based on a frequency-shifted form of binary phase shift keying (S-BPSK), relaxing the constant-envelope requirement for the illuminator and an illumination-agnostic detector is derived. Based on S-BPSK, short packet error correction coding is utilized for ambient backscatter communication, for the first time in the literature. It is shown that the proposed coded scheme under modulated ambient signal illumination & wireless channel variation, offers tremendous performance gains, i.e., modulation of the ambient signal is helpful. Finally, a third, purely analog, modulation scheme is analyzed, based on FM remodulation principles. A low-cost tag is implemented, demonstrating tag-to-receiver ranges up to 26 meters outdoors, power consumption of ${24} ~\mu $ Watts in continuous operation, able to be interrogated by any conventional frequency modulation (FM) receiver. The proposed techniques cover a large variety of omnipresent wireless industry systems, enabling universal ambient backscatter and relevant wireless information and power transfer (WIPT) applications.

54 citations

Journal ArticleDOI
TL;DR: This work proposes a low-cost technique for simultaneous and independent optical signal-to-noise ratio (OSNR), chromatic dispersion, and polarization-mode dispersion monitoring in 40/56-Gb/s return- to-zero differential quadrature phase-shift keying and RZ-DQPSK systems.
Abstract: We propose a low-cost technique for simultaneous and independent optical signal-to-noise ratio (OSNR), chromatic dispersion (CD), and polarization-mode dispersion (PMD) monitoring in 40/56-Gb/s return-to-zero differential quadrature phase-shift keying (RZ-DQPSK) and 40-Gb/s RZ-DPSK systems, using artificial neural networks (ANN) trained with empirical moments of asynchronously sampled signal amplitudes. The proposed technique employs an extremely simple hardware and digital signal processing to enable multi-impairment monitoring at different data rates and for various modulation formats without necessitating hardware changes. Simulation results demonstrate wide dynamic ranges and good monitoring accuracies.

54 citations

Journal ArticleDOI
TL;DR: In this article, a receiver structure for random Gaussian signals in additive noise based on the classic maximum likelihood (M-L), estimator-correlator derivation of Kailath [1960] was developed and applied to differential phase shift keying (DPSK) on the correlated Rayleigh-fading channel.
Abstract: The paper develops a receiver structure for random Gaussian signals in additive noise based on the classic maximum likelihood (M-L), estimator-correlator derivation of Kailath [1960], and applies it to differential phase shift keying (DPSK) on the correlated Rayleigh-fading channel. It is shown to lower the error floor found in the performance of conventional DPSK receivers by orders of magnitude. In addition, the maximum-likelihood procedure is shown to make uncorrelated symbol decisions. The performance of both conventional and optimal receivers, which require knowledge of the channel statistics, is examined analytically. A recursive, channel-adaptive version of the optimal receiver, utilizing decision feedback to estimate the channel statistics, is developed. Its simulated performance shows no penalty compared to theoretical calculations which require explicit knowledge of the channel statistics. >

54 citations

Patent
08 Aug 2005
TL;DR: In this paper, a method and apparatus for manufacturing trusted devices is described, where a licensing authority provides keying information to a multitude of manufactures that insert the keying into trusted devices.
Abstract: The present invention discloses a method and apparatus for manufacturing trusted devices. A licensing authority provides keying information to a multitude of manufactures that insert the keying information into trusted devices. The trusted devices generate final private and public keys using the keying information. The keys may then be certified by the manufacture and verified by other devices.

54 citations


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