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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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Proceedings ArticleDOI
03 Oct 2016
TL;DR: Throughout experiments and log analysis of 2nd screen service deployed in a nation-wide TV broadcasting system, J-shape detection algorithms are proven to achieve highly resilient performance for both frame synchronization and carrier sensing compared to previous schemes.
Abstract: In this paper, we propose a near-ultrasound chirp signal-based communication for the TV's 2nd screen services. While near-ultrasound (with under 20 kHz frequency) communication has been developed for various applications recently, none of the previous work provides a perfect solution for 2nd screen services between TVs and smart devices. This is due mainly to the following real world challenges. The embedded signal in TV contents should be successfully received in a typical TV-watching environment by (i) delivering information at least at 15 bps with significantly low volume to avoid human perception, (ii) despite the presence of ambient noise, e.g., a tick, a snap, or a knock. To fulfill (i), we design chirp quaternary orthogonal keying (QOK) symbols. Especially, we aim to minimize inter-symbol interference (ISI) effects by symbol design in order to completely eliminate guard intervals. To resolve (ii), we propose the novel J-shape detection algorithms for both frame synchronization and carrier sensing. The proposed modem achieves almost zero frame error rate on a smartphone 2.7 m away from the TV even with minimal receive sound pressure level of 35 dBSPL, i.e., the noise level in a very quiet room. Moreover, throughout experiments and log analysis of 2nd screen service deployed in a nation-wide TV broadcasting system, J-shape detection algorithms are proven to achieve highly resilient performance for both frame synchronization and carrier sensing compared to previous schemes.

36 citations

Journal ArticleDOI
TL;DR: This study compares these algorithms in terms of classification accuracy and execution time for either estimating the modulation order, determining centroid locations, or both and proposes an AMC method suitable for applications such as spectrum monitoring and regulatory enforcement.
Abstract: In this paper, the k-means, k-medoids, fuzzy c-means, Density-Based Spatial Clustering of Applications with Noise (DBSCAN), Ordering Points To Identify the Clustering Structure (OPTICS), and hierarchical clustering algorithms (with the addition of the elbow method) are examined for the purpose of Automatic Modulation Classification (AMC). This study compares these algorithms in terms of classification accuracy and execution time for either estimating the modulation order, determining centroid locations, or both. The best performing algorithms are combined to provide a simple AMC method which is then evaluated in an Additive White Gaussian Noise (AWGN) channel with M-Quadrature Amplitude Modulation (QAM) and M-Phase Shift Keying (PSK). Such an AMC method does not rely on any thresholds to be set by a human or machine learning algorithm, resulting in a highly flexible system. The proposed method can be configured to not give false positives, making it suitable for applications such as spectrum monitoring and regulatory enforcement.

36 citations

Journal ArticleDOI
TL;DR: Time-modulated frequency diverse multiple-input–multiple-output (TMFD-MIMO) array for integrated radar and communications, where the communication information bits are embedded via spread sequence technique during each radar pulse, achieves satisfactory probability of target resolution and signal-to-interference-plus-noise ratio.
Abstract: In this letter, we explore time-modulated frequency diverse multiple-input–multiple-output (TMFD-MIMO) array for integrated radar and communications, where the communication information bits are embedded via spread sequence technique during each radar pulse. Orthogonal waveforms are adopted in the TMFD-MIMO array for radar functionality, and a switching time-modulation scheme is applied according to the information bits, i.e., binary phase-shift keying (BPSK) associated spreading sequences. Thus, the number of embedded information bits during each radar pulse equals the number of spread sequences. In doing so, the communication receiver interprets the bits associated with a particular waveform as binary information with prior knowledge of the spread sequences. When compared with existing radar-communications, the achievable data rate is then proportionally increased with the pulse repetition frequency, spreading sequence, and size of the BPSK constellation. Moreover, satisfactory probability of target resolution and signal-to-interference-plus-noise ratio for radar functionality and symbol error rate for communication functionality are achieved.

36 citations

Journal ArticleDOI
TL;DR: In this article, the effect of delaying by a small and irregular amount of activation of the print unit attached to a teletype keyboard was investigated and the results were not consistent with the open-loop or closed-loop hypothesis of keying performance.
Abstract: Five experiments are reported which assessed the effect on unskilled and skillod keying performance of delaying by a small and irregular amount tho activation of the print unit attached to a teletype keyboard. The first three experiments involving unskilled subjocts showed: a significant decrease in the speed of performance; tho persistence of tho impairment over extended testing; and the occurrence of the effect even when a modified transcription task permitted faster keying. The remaining experiments involving skilled subjects showed: a decrease in the speod of performance; an association of the impairment with an increase in the longer interrosponse times; the elimination of tho effect after an initial exposure to tho delay. Those experimental outcomes are not consistent either with the open-loop or the closed-loop hypothesis of keying performance suggested by theories of motor learning. A modified version of each hypothesis is proposed, tormod ’ adaptation ’ and ’ substitution ’ respectively. Both mod...

36 citations

Journal ArticleDOI
TL;DR: The effects of two types of path diversity techniques, namely selection diversity and maximal ratio combining, on the bit error probability are investigated for direct-sequence spread-spectrum (DS/SS) transmission in a land mobile satellite channel using coherent binary phase-shift keying (BPSK) modulation.
Abstract: The effects of two types of path diversity techniques, namely selection diversity and maximal ratio combining, on the bit error probability are investigated for direct-sequence spread-spectrum (DS/SS) transmission in a land mobile satellite channel using coherent binary phase-shift keying (BPSK) modulation. It is assumed that the channel consists of a log-normally shadowed line-of-sight signal plus Rayleigh distributed multipath signals. The bit error probability is evaluated for light, average, and heavy shadowing. The performance is also measured in terms of the outage probability. >

36 citations


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