scholarly journals Realization of multiplierless coherent detection scheme in digital domain

1988 ◽  
Vol 76 (10) ◽  
pp. 1394-1395
Author(s):  
Kang Cheol-Ho ◽  
Ryu Heunggyoon ◽  
C.H. Lee
Keyword(s):  
Coherent Detection ◽  
Detection Scheme

scholarly journals Advanced Noncoherent Detection in Massive MIMO Systems via Digital Beamspace Preprocessing

Telecom ◽  
2020 ◽  
Vol 1 (3) ◽  
pp. 211-227
Author(s):  
Stephan Bucher ◽  
Christian Waldschmidt
Keyword(s):  
Mimo Systems ◽  
Near Field ◽  
Multiple Input Multiple Output ◽  
Low Complexity ◽  
Base Station ◽  
Coherent Detection ◽  
Noncoherent Detection ◽  
Detection Scheme ◽  
Channel Knowledge ◽  
Residual Performance

Noncoherent detection in massive multiple-input/multiple-output (MIMO) uplink systems provides a low-complexity alternative to its coherent counterpart. Requiring no actual channel knowledge but the per-user induced power at the base station, comparable performance as channel-estimation-based detection can be achieved when the users are located in the near-field of the base station. However, noncoherent detection fails in scenarios where users are in the far-field due to an insufficient capability to separate the users in terms of their spatially induced power. For this purpose, a dielectric lens or an analog beamforming structure can be employed, which are capable to focus the power of the incident waves to a smaller subset of the antennas at the base station. These so-called analog beamspace techniques have been demonstrated to enable again the noncoherent detection scheme. Analogous to a spatial Fourier transform, beamspace techniques can be also realized in the digital domain offering more flexibility. Its applicability to noncoherent detection is studied in this paper. It is shown numerically that by means of digital beamspace preprocessing, considerable performance gains can be achieved. Applied in dominant line-of-sight channels, a large number of users can be accommodated and the residual performance gap to coherent detection with perfect channel knowledge is minimal.

Laser-Phase-Fluctuation-Insensitive Optical Coherent Detection Scheme for Radio-over-Fiber System

2014 ◽  
Vol 32 (20) ◽  
pp. 3803-3809 ◽  
Author(s):  
Toshiaki Kuri ◽  
Takahide Sakamoto ◽  
Guo-Wei Lu ◽  
Tetsuya Kawanishi
Keyword(s):  
Phase Fluctuation ◽  
Radio Over Fiber ◽  
Coherent Detection ◽  
Fiber System ◽  
Detection Scheme ◽  
Radio Over Fiber System

scholarly journals Generation and coherent detection of QPSK signal using a novel method of digital signal processing

2018 ◽  
Vol 32 (04) ◽  
pp. 1850103
Author(s):  
Yuan Zhao ◽  
Bingliang Hu ◽  
Zhen-An He ◽  
Wenjia Xie ◽  
Xiaohui Gao
Keyword(s):  
Signal Processing ◽  
Digital Signal Processing ◽  
Digital Signal ◽  
Local Oscillator ◽  
Coherent Detection ◽  
Detection Methods ◽  
Homodyne Detection ◽  
Modulation Formats ◽  
Detection Scheme ◽  
Labview Software

We demonstrate an optical quadrature phase-shift keying (QPSK) signal transmitter and an optical receiver for demodulating optical QPSK signal with homodyne detection and digital signal processing (DSP). DSP on the homodyne detection scheme is employed without locking the phase of the local oscillator (LO). In this paper, we present an extracting one-dimensional array of down-sampling method for reducing unwanted samples of constellation diagram measurement. Such a novel scheme embodies the following major advantages over the other conventional optical QPSK signal detection methods. First, this homodyne detection scheme does not need strict requirement on LO in comparison with linear optical sampling, such as having a flat spectral density and phase over the spectral support of the source under test. Second, the LabVIEW software is directly used for recovering the QPSK signal constellation without employing complex DSP circuit. Third, this scheme is applicable to multilevel modulation formats such as M-ary PSK and quadrature amplitude modulation (QAM) or higher speed signals by making minor changes.

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