A Novel Channel Estimation Method Based on Power-Delay Profile

2014 ◽  
Vol 602-605 ◽  
pp. 2871-2877
Author(s):  
Ying Xin Yu ◽  
Gang Wang
Keyword(s):  
Impulse Response ◽  
Estimation Method ◽  
Wiener Filter ◽  
Doppler Frequency ◽  
Estimation Algorithm ◽  
Wireless Channel ◽  
Least Square ◽  
Channel Impulse Response ◽  
Power Delay Profile ◽  
Mmse Estimation

Considering the physical layer specification of the IEEE802.11 protocol as background, a novel LSE (least square estimation) algorithm based on power-delay profile of wireless channel is proposed. In multi-path time-variant channel, receiver carries out a primary MMSE estimation using training symbols and pilots of OFDM symbol firstly. Then the channel impulse response is obtained from frequency response estimated by MMSE. Finally, LSE algorithm is applied to revise the channel impulse response according to the power-delay profile. The LSE algorithm can reduce the noise level of MMSE estimation in time-domain which is equivalent to increasing the SNR to the output of 2-D wiener filter. Simulation results confirm that the proposed LSE algorithm gains a better performance in contrast to MMSE algorithm. As the Doppler frequency shift increases, LSE outperforms more significantly than MMSE algorithm.

scholarly journals Method of Doppler Frequency Spread Estimation for High-Mobility OFDM Systems

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Feng Zhao ◽  
Xihong Sun
Keyword(s):  
Autocorrelation Function ◽  
Orthogonal Frequency Division Multiplexing ◽  
Estimation Error ◽  
High Mobility ◽  
Doppler Frequency ◽  
Estimation Algorithm ◽  
Least Square ◽  
Ofdm Systems ◽  
Frequency Spread ◽  
Spread Estimation

A method of Doppler frequency spread (DFS) estimation algorithm is discussed which is suitable for high-mobility Orthogonal Frequency Division Multiplexing (OFDM) systems. DFS is a main factor which may mitigate the performance of system. The proposed method is based on autocorrelation function algorithm of received signal which utilizes cyclic prefix (CP) to estimate Doppler spread. The estimation algorithm uses least square (LS) method between the autocorrelation function of received signal and the zero-order Bessel function which is approximated by the expansion of power series. Then the estimation bias is analyzed and using polynomial fitting method can effectively correct estimation error at different DFS, respectively. Compared with the previously proposed method, the estimation performance of DFS in the proposed method has better performance. Simulation results show that when sufficient elements are used, the proposed scheme can effectively estimate DFS and can be applied into high-mobility OFDM systems.

scholarly journals Performance Evaluation of GFDM Channel Estimation Using DFT for Tactile Internet Application

Electronics ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 595
Author(s):  
Al Kautsar Permana ◽  
Effrina Yanti Hamid
Keyword(s):  
Channel Estimation ◽  
Impulse Response ◽  
Channel Model ◽  
Estimation Algorithm ◽  
Symbol Error Rate ◽  
Least Square ◽  
Channel Response ◽  
Macro Cell ◽  
Pilot Symbols ◽  
Internet Application

In this work, discrete Fourier transform (DFT)-based channel estimation is proposed in generalized frequency division multiplexing (GFDM) system. In the GFDM system, the subcarriers are non-orthogonal; therefore, the pilot symbols cannot be easily observed due to the interference from data symbols and noise. The proposed method can improve the channel estimation of least square (LS) method by eliminating channel impulse response outside the number of actual impulse response. First, the received signal is demodulated using zero forcing demodulator. Then, it is divided with transmitted pilot symbols to obtain channel response. Interpolation in frequency and time domains is conducted to acquire channel response for all GFDM blocks. Finally, the channel estimation algorithm using DFT is performed. The parameters of the system are adjusted so that they are suitable for tactile internet application. The channel model used is NYUSIM, which utilizes mmWave. Three scenarios in NYUSIM such as urban microcell, urban macro cell and rural macro cell are used and power delay profiles generated from NYUSIM simulator are employed in this system. The results show that mean square error (MSE) from DFT-based channel estimation gives substantial improvement for all scenarios. In addition, symbol error rate (SER) of DFT-based channel estimation provides a slight improvement of 1.5 dB than LS channel estimation.

A Simplified Time-Domain Channel Estimation Approach for OFDM System

2015 ◽  
Vol 738-739 ◽  
pp. 1111-1114
Author(s):  
Sheng Bo Huang ◽  
Yu Cang Wen ◽  
Wen Ye ◽  
Tong Liang Fan
Keyword(s):  
Channel Estimation ◽  
Impulse Response ◽  
Time Domain ◽  
Estimation Method ◽  
Channel Impulse Response ◽  
Estimation Algorithms ◽  
Estimation Scheme ◽  
Time Domain Averaging ◽  
The Time Domain ◽  
Effective Channel

OFDM usually incorporates pilot tones in the frequency domain (FD) or training symbols in the time-domain (TD) to facilitate channel estimation algorithms. TD channel estimation becomes more attractive in quasi-static channels because channel estimation scheme will optimize the spectral efficiency by re-using the training symbols designated for FD channel estimation. A channel estimation method based on time domain averaging algorithm is proposed. Due to the principle of centralized energy in time domain, the effective channel impulse response length can be detected by setting of threshold for the estimated channel impulse response length. Computer simulation demonstrates the performance of the proposed algorithms in terms of bit error rate performance.

scholarly journals Estimation of Compressible Channel Impulse Response for OFDM Modulated Transmissions

Electronics ◽  
2021 ◽  
Vol 10 (22) ◽  
pp. 2781
Author(s):  
Grzegorz Dziwoki ◽  
Marcin Kucharczyk
Keyword(s):  
Compressed Sensing ◽  
Impulse Response ◽  
Signal To Noise Ratio ◽  
Least Square ◽  
Channel Impulse Response ◽  
Reconstruction Method ◽  
Reconstruction Procedure ◽  
Initial Block ◽  
User Data ◽  
Estimation Scheme

Channel estimation scheme for OFDM modulated transmissions usually combines an initial block-pilot-assisted stage with a tracking one based on comb or scattered pilots distributed among user data in the signal frame. The channel reconstruction accuracy in the former stage has a significant impact on tracking efficiency of the channel variations and the overall transmission quality. The paper presents a new block-pilot-assisted channel reconstruction procedure based on the DFT-based approach and the Least Square impulse response estimation. The proposed method takes into account a compressibility feature of the channel impulse response and restores its coefficients in groups of automatically controlled size. The proposition is analytically explained and tested in a OFDM simulation environment. The popular DFT-based methods including compressed sensing oriented one were used as references for comparison purposes. The obtained results show a quality improvement in terms of Bit Error Rate and Mean Square Error measures in low and mid ranges of signal-to-noise ratio without significant computational complexity growth in comparison to the classical DFT-based solutions. Moreover, additional multiplication operations can be eliminated, compared to the competitive, in terms of estimation quality, compressed sensing reconstruction method based on greedy approach.

scholarly journals Golay Code Based Bit Mismatch Mitigation for Wireless Channel Impulse Response Based Secrecy Generation

IEEE Access ◽  
2018 ◽  
pp. 1-1 ◽  
Author(s):  
Chen Shen ◽  
Hao Li ◽  
Gokhan Sahin ◽  
Hyeong-Ah Choi ◽  
Yogendra Shah
Keyword(s):  
Impulse Response ◽  
Wireless Channel ◽  
Channel Impulse Response ◽  
Golay Code

scholarly journals Sparse iterative covariance-based estimation approach for processing atmospheric radar data

2018 ◽  
Vol 7 (1.8) ◽  
pp. 232 ◽  
Author(s):  
Raju C ◽  
Sreenivasulu Reddy T
Keyword(s):  
Wind Speed ◽  
Estimation Method ◽  
Doppler Frequency ◽  
Estimation Algorithm ◽  
Radar Data ◽  
Spectrum Estimation ◽  
Power Spectral ◽  
Global Positioning ◽  
Mst Radar ◽  
Gradient Approach

The Doppler estimation is an important problem for Mesosphere–Stratosphere–Troposphere (MST) Radar data for detection and estimation of the weather parameters like turbulence intensity, mean radial velocity, humidity, temperature, wind speed. For Doppler estimation, one has to compute the Power Spectral Density (PSD). Various parametric and nonparametric methods have been developed. Recently, a new category of spectrum estimation method called Sparse Iterative Covariance Based Estimation (SPICE) is also developed. SPICE is a robust, user parameter-free, high resolution, iterative and globally convergent estimation algorithm. In this paper, the simple gradient approach is used for minimization of the weighted covariance estimation analyzing the data collected from the Indian MST radar at Gadanki (13.5°N, 79.2°E). The same method is applied for radar data to estimate the power spectrum and Doppler frequency. The zonal (U), meridional (V), wind speed (W) are calculated and the results have been validated using simultaneous Global Positioning System (GPS) Sonde data.

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