Keying

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

Design and Implementation of a Tree-Based Blind Modulation Classification Algorithm for Multiple-Antenna Systems

Abstract: This paper presents the design and testbed implementation of a tree-based algorithm, which classifies many of the linearly modulated signals, such as binary phase-shift keying (PSK), quadrature PSK (QPSK), offset QPSK, $\pi $ /4-QPSK, 8-PSK, minimum shift keying, and 16-quadrature amplitude modulation. The proposed modulation classification algorithm is applicable to spatially multiplexed multiple antenna systems over frequency-selective fading channels. It works in the presence of timing, phase, and frequency offsets, without having prior knowledge of the channel state information. Classification is performed by utilizing the combined properties of the correlation functions, cyclic cumulant (CC), and cumulant. The correlation function of the received baseband signal exhibits peaks at a particular set of time lag, which represents distinctive features for the modulation formats. The CC uses the position of nonzero cycle frequency of the received baseband signals to classify modulation formats, while the cumulant employs threshold values. To authenticate the proposed algorithm, implementation and measurement are performed in an indoor propagation environment by using a National Instrument testbed setup. The performance of the proposed algorithm is compared with existing methods via Monte Carlo simulations.

A novel approach to photonic generation of RF binary digital modulation signals.

Abstract: A novel approach to photonically generate binary digital modulation radio frequency (RF) signals is proposed. In the proposed system, the short optical pulses are converted into high frequency RF signals based on optical pulse shaping followed by dispersion induced frequency-to-time mapping technique. And the generated signals are coded using a fast electro-optical switch based on polarization modulation. By properly configuring the system, binary digital modulation signals, including amplitude-shift keying (ASK), frequency-shift keying (FSK) and phase-shift keying (PSK) with required bit pattern are generated in the optical domain. A model describing the signal generation system is derived, which is verified via both simulations and a proof-of-concept experiment.

Channel Coding for Underwater Acoustic Communication System

Abstract: GESMA (Groupe d'Etudes Sous-Marines de l'Atlantique) objective is to develop a sufficiently robust acoustic link allowing the transmission of different information (text, images...). A real-time platform named TRIDENT (TRansmission d'Images et de Donnes EN Temps reel) was designed at ENST Bretagne. A blind spatio-temporal equalizer is used to reduce the various perturbations brought by the underwater acoustic channel (UWA). The acoustic link performances was evaluated and shown its robustness for transmission in a strongly disturbed channel. GESMA also wants to increase the link reliability and provides strongly protected low bit rate speech (MELP, 2400 bps) transmission. In order to do so, a channel coding will be added to the system. Different kinds of error correcting scheme will be tested including Convolutional Codes (CC) and Reed Solomon (RS) block code. A Differential Phase-Shift Keying (DPSK) is used to solve phase ambiguities in case of CC coding and Viterbi decoding utilization.

Optical phase erasure based on FWM in HNLF enabling format conversion from 320-Gb/s RZDQPSK to 160-Gb/s RZ-DPSK.

Abstract: Through four-wave mixing (FWM) process in highly-nonlinear fiber (HNLF) or semiconductor device, the phase-modulation depth of one converted FWM component could be doubled compared with that of the original input signal Therefore, with a multilevel phase-modulated signal and a CW light as inputs, after FWM process in a nonlinear media, phase pattern (0, π) carried in the input multilevel phase-modulated signal will not be transferred to one converted FWM component, which could be referred to as an optical phase erasure process We experimentally demonstrated format conversion from 320-Gb/s return-to-zero differential quadrature phase-shift keying (RZ-DQPSK) to 160-Gb/s return-to-zero differential phase-shift keying (RZ-DPSK) through the proposed all-optical phase erasure scheme The phase information carried in the converted binary RZ-DPSK is logically equal to the input Q-component, or a logical XOR operation result between I and Q components of the input RZ-DQPSK, which correspond to a serial or parallel DQPSK transmitter for the input RZ-DQPSK signal It can be applied to erase a binary tributary from a multilevel modulation format

Spectrum efficiency of GMSK land mobile radio

Abstract: Gaussian-filtered minimum-shift keying (GMSK) is a constant envelope and narrow-band modulation suitable for power- and band-limited digital radio communication. From the viewpoint of efficient spectrum use by land mobile radio, geographical reuse of cochannels as well as power spectrum compactness are desired. The output power spectrum of GMSK modulation can be made compact, at a sacrifice of co-channel interference protection. Parameters for optimizing GMSK are determined maintaining a compromise between co-channel reuse and power spectrum compactness.