Computationally Efficient Single-Frequency Estimation Scheme in High-Rate WPAN Systems

2013 ◽  
Vol 72 (1) ◽  
pp. 521-533 ◽  
Author(s):  
Won-Jae Shin ◽  
Jeongwook Seo ◽  
Young-Hwan You
Keyword(s):  
Frequency Estimation ◽  
High Rate ◽  
Single Frequency ◽  
Computationally Efficient ◽  
Estimation Scheme

scholarly journals Critical Review of Basic Methods on DoA Estimation of EM Waves Impinging a Spherical Antenna Array

Electronics ◽  
2022 ◽  
Vol 11 (2) ◽  
pp. 208
Author(s):  
Oluwole John Famoriji ◽  
Thokozani Shongwe
Keyword(s):  
Antenna Array ◽  
Frequency Estimation ◽  
Time Windows ◽  
Doa Estimation ◽  
Single Frequency ◽  
Computationally Efficient ◽  
Spherical Antenna ◽  
Line Of Sight Propagation ◽  
The Difference ◽  
Highly Correlated

Direction-of-arrival (DoA) estimation of electromagnetic (EM) waves impinging on a spherical antenna array in short time windows is examined in this paper. Reflected EM signals due to non-line-of-sight propagation measured with a spherical antenna array can be coherent and/or highly correlated in a snapshot. This makes spectral-based methods inefficient. Spectral methods, such as maximum likelihood (ML) methods, multiple signal classification (MUSIC), and beamforming methods, are theoretically and systematically investigated in this study. MUSIC is an approach used for frequency estimation and radio direction finding, ML is a technique used for estimating the parameters of an assumed probability distribution for given observed data, and PWD applies a Fourier transform to the capture response and produces them in the frequency domain. Although they have been previously adapted and used to estimate DoA of EM signals impinging on linear and planar antenna array configurations, this paper investigates their suitability and effectiveness for a spherical antenna array. Various computer simulations were conducted, and plots of root-mean-square error (RMSE) against the square root of the Cramér–Rao lower bound (CRLB) were generated and used to evaluate the performance of each method. Numerical experiments and results from measured data show the degree of appropriateness and efficiency of each method. For instance, the techniques exhibit identical performance to that in the wideband scenario when the frequency f = 8 GHz, f = 16 GHz, and f = 32 GHz, but f = 16 GHz performs best. This indicates that the difference between the covariance matrix of the signal is coherent and that the steering vectors of signals impinging from that angle are small. MUSIC and PWD share the same problems in the single-frequency scenario as in the wideband scenario when the delay sample d = 0. Consequently, the DoA estimation obtained with ML techniques is more suitable, less biased, and more robust against noise than beamforming and MUSIC techniques. In addition, deterministic ML (DML) and weighted subspace fitting (WSF) techniques show better DoA estimation performance than the stochastic ML (SML) technique. For a large number of snapshots, WSF is a better choice because it is more computationally efficient than DML. Finally, the results obtained indicate that WSF and ML methods perform better than MUSIC and PWD for the coherent or partially correlated signals studied.

scholarly journals Computationally Efficient Robust Chinese Remainder Theorem for Frequency Estimation from Undersampled Waveforms

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Xiaoping Li ◽  
Wenjie Wang ◽  
Bobin Yao ◽  
Bin Yang ◽  
Qinye Yin
Keyword(s):  
Robust Estimation ◽  
Chinese Remainder Theorem ◽  
Frequency Estimation ◽  
Optimal Estimation ◽  
Single Frequency ◽  
Necessary Condition ◽  
Optimal Estimate ◽  
Computationally Efficient ◽  
Numerical Examples ◽  
Sufficient And Necessary Condition

We present an efficient algorithm based on the robust Chinese remainder theorem (CRT) to perform single frequency determination from multiple undersampled waveforms. The optimal estimate of common remainder in robust CRT, which plays an important role in the final frequency estimation, is first discussed. To avoid the exhausted searching in the optimal estimation, we then provide an improved algorithm with the same performance but less computation. Besides, the sufficient and necessary condition of the robust estimation was proposed. Numerical examples are also provided to verify the effectiveness of the proposed algorithm and related conclusions.

scholarly journals Complexity Effective Sampling Frequency Offset Estimation Method for OFDM-Based HomePlug Green PHY Systems

Symmetry ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 544
Author(s):  
Yong-An Jung ◽  
Young-Hwan You
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Estimation Method ◽  
Frequency Offset ◽  
Sampling Frequency ◽  
Estimation Accuracy ◽  
Computationally Efficient ◽  
Pilot Symbols ◽  
Sampling Frequency Offset ◽  
Efficient Sampling ◽  
Estimation Scheme

The HomePlug Green PHY (HomePlug GP) specification provides an attractive solution to enable smart grid power line communication (PLC) applications by using robust orthogonal frequency division multiplexing (ROBO) mode. This paper proposes a computationally efficient sampling frequency offset (SFO) estimation technique in the HomePlug GP system without relying on pilot symbols. For this purpose, the proposed estimation scheme utilizes the redundant information contained within the repeat coding in the HomePlug GP ROBO mode, thus eliminating the need of dedicated pilots. Computer simulations are conducted to assess the performance of the proposed SFO estimation scheme and to compare it with the conventional decision-directed (DD) estimation schemes. Simulations indicate that the repeat coded ROBO signals are effectively used for the proposed estimation scheme, which provides an affordable estimation accuracy while reducing the complexity compared to the conventional DD estimation schemes.

A Model-Based Computationally Efficient Method for On-Line Detection of Chatter in Milling

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Lei Ma ◽  
Shreyes N. Melkote ◽  
James B. Castle
Keyword(s):  
Cutting Force ◽  
Efficient Method ◽  
Frequency Estimation ◽  
Chip Thickness ◽  
Computationally Efficient ◽  
Model Based ◽  
Chatter Suppression ◽  
Force Signal ◽  
Regeneration Effect ◽  
Milling Chatter

This paper presents a model-based computationally efficient method for detecting milling chatter in its incipient stages and for chatter frequency estimation by monitoring the cutting force signals. Based on a complex exponentials model for the dynamic chip thickness, the chip regeneration effect is amplified and isolated from the cutting force signal for early chatter detection. The proposed method is independent of the cutting conditions. With the aid of a one tap adaptive filter, the method is shown to be capable of distinguishing between chatter and the dynamic transients in the cutting forces arising from sudden changes in workpiece geometry and tool entry/exit. To facilitate chatter suppression once the onset of chatter is detected, a time domain algorithm is proposed so that the dominant chatter frequency can be accurately determined without using computationally expensive frequency domain transforms such as the Fourier transform. The proposed method is experimentally validated.

Sign in / Sign up

Export Citation Format

Share Document