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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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14 Apr 2019
TL;DR: The findings reveal that LIS-based IM, which enables ultra-reliable transmission with high spectral efficiency, can become a potential candidate for future wireless communication systems in the context of beyond massive multiple-input multiple-output (MIMO) solutions.
Abstract: Transmission through large intelligent surfaces (LIS), which modify the phases of incident waves in a deliberate manner to enhance the signal quality at the receiver, has been recently put forward as a promising candidate for future wireless communication systems and standards. In this paper, we bring the concept of LIS-assisted communications to the realm of index modulation (IM) by proposing LIS-space shift keying (LIS-SSK) and LIS-spatial modulation (LIS-SM) schemes. These two schemes are realized through not only intelligent reflection of the incoming electromagnetic waves to improve the signal quality at the receiver but also utilization of the IM principle for the indices of multiple receive antennas in a clever way to improve the spectral efficiency. Maximum energy-based suboptimal (greedy) and exhaustive search-based optimal (maximum likelihood) detectors of the LIS-SSK/SM schemes are formulated and a unified framework is presented for the derivation of the theoretical average bit error probability of the proposed schemes using both detectors. Extensive computer simulation results are provided to assess the potential of LIS-assisted IM schemes as well as to verify our theoretical derivations and remarks. Our findings also reveal that LIS-based IM, which enables ultra-reliable transmission with high spectral efficiency, can become a potential candidate for future wireless communication systems in the context of beyond massive multiple-input multiple-output (MIMO) solutions.

64 citations

Journal ArticleDOI
TL;DR: The findings suggest that pointing error compensation is necessary as pointing errors can severely degrade the error rate and outage probability performance of an uncompensated system.
Abstract: An optical wireless communication system using subcarrier intensity modulation is analyzed for gamma-gamma turbulence channels with pointing errors We study the error rate performance of such a system employing M-ary phase-shift keying, differential phase-shift keying, and noncoherent frequency-shift keying Highly accurate error rate approximations are derived using a series expansion approach Furthermore, outage probability expressions are obtained for such a system Asymptotic error rate and outage probability analyses are also presented Our asymptotic analysis reveals some unique transmission characteristics of such a system Our findings suggest that pointing error compensation is necessary as pointing errors can severely degrade the error rate and outage probability performance of an uncompensated system

64 citations

Journal ArticleDOI
TL;DR: It is shown that intersymbol interference induced by multipath propagation impairs detection efficiency, and an adaptive decision-feedback equalizer adapted according to the least-mean-squares algorithm recovers most of the performance degradation.
Abstract: We investigate 100 Mb/s wireless nondirectional infrared communication in the indoor environment using baseband nonreturn-to-zero (NRZ) on-off keying (OOK) modulation. We show that intersymbol interference induced by multipath propagation impairs detection efficiency. Analytical and simulation results on specific channels demonstrate that an adaptive decision-feedback equalizer adapted according to the least-mean-squares algorithm recovers most of the performance degradation. We also evaluate the performance of a timing-recovery phase-locked loop operating independent of the adaptive equalizer; showing that it quickly and accurately determines the sampling phase with negligible performance degradation. We discuss effective methods of mitigating low-frequency noise induced by fluorescent lighting. We present a packet-based communication method and describe its features and performance. Our results support the feasibility of communication at 100 Mb/s over the infrared channel. >

63 citations

Journal ArticleDOI
TL;DR: The principle, implementation, and performance of a recently introduced high-sensitivity modulation format based on the combined use of polarization-division-multiplexed quadrature phase-shift keying and m-ary pulse-position modulation, termed PQ-mPPM, is presented.
Abstract: We present the principle, implementation, and performance of a recently introduced high-sensitivity modulation format based on the combined use of polarization-division-multiplexed quadrature phase-shift keying (PDM-QPSK, or PQ) and m-ary pulse-position modulation (m-PPM). This novel modulation format, termed PQ-mPPM, offers high receiver sensitivity in optically preamplified receivers. We study the sensitivity of the PQ-mPPM format both analytically and experimentally, and compare it to common modulation formats such as PDM-QPSK, m-PPM, differential phase-shift keying, and polarization-switched QPSK. The bandwidth expansion factor of this format is also discussed. A record sensitivity of 3.5 photons per bit at BER = 10-3 is experimentally demonstrated at 2.5 Gb/s with a novel pilot-assisted digital coherent-detection scheme, outperforming PDM-QPSK by about 3 dB.

63 citations

Patent
Tom Haldorsen1
28 May 2004
TL;DR: An inkjet printer and inkjet print cartridge are each especially configured for inter-engaging with one another via a plurality of keying features of the cartridge and keying structures of the printer such that loading of a foreign print cartridge into the printer is either not possible or results in the printer being inoperative as discussed by the authors.
Abstract: An inkjet printer and inkjet print cartridge are each especially configured for inter-engaging with one another via a plurality of keying features of the cartridge and keying structures of the printer such that loading of a foreign print cartridge into the printer is either not possible or results in the printer being inoperative. Thus, only print cartridges particularly configured and intended to be used in the printer will fit into the printer and enable its operation.

63 citations


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