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.

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.

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.

Model Optimization and Stability of Hemoglobin Analysis in Human Soluble Blood Samples by FTIR/ATR Spectroscopy

2011 ◽  
Vol 55-57 ◽  
pp. 1168-1171
Author(s):  
Tao Pan ◽  
Ai Hong Peng ◽  
Wen Jie Huang
Keyword(s):  
Signal To Noise Ratio ◽  
Attenuated Total Reflection ◽  
Partial Least Square ◽  
Least Square ◽  
Model Optimization ◽  
Optimal Model ◽  
Blood Samples ◽  
Quantification Method ◽  
Atr Spectroscopy ◽  
Pls Method

Using Fourier transform infrared spectroscopy (FTIR), attenuated total reflection (ATR) technology and partial least square (PLS) method, the rapid quantification method of hemoglobin (HGB) in human soluble blood samples was established. Based on the distribution of samples’ HGB chemical value and absorbance on 1543 cm-1 which had the highest signal to noise ratio for HGB, all samples were divided into calibration set and prediction set for 50 times. PLS models were established for all divisions, based on the average data RMSEPAve, the stable optimal model was selected, the corresponding PLS factor, RMSEPAve and RP,Ave were 2, 6.81 g/L and 0.943 respectively.

scholarly journals Channel Sounding for the Masses: Low Complexity GNU 802.11b Channel Impulse Response Estimation

2012 ◽  
Vol 11 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Dustin Maas ◽  
Mohammad H. Firooz ◽  
Junxing Zhang ◽  
Neal Patwari ◽  
Sneha K. Kasera
Keyword(s):  
Impulse Response ◽  
Low Complexity ◽  
Channel Impulse Response ◽  
Channel Sounding ◽  
The Masses
Sign in / Sign up

Export Citation Format

Share Document