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.

Improving Space-Time-Frequency MIMO-OFDM with ICI Self-Cancellation Scheme using Least Square Error Estimator

2015 ◽  
Vol 12 (1) ◽  
pp. 25
Author(s):  
Nur Farahiah Ibrahim ◽  
Zahari Abu Bakar ◽  
Azlina Idris
Keyword(s):  
Channel Estimation ◽  
Orthogonal Frequency Division Multiplexing ◽  
Symbol Error Rate ◽  
Space Time ◽  
Least Square ◽  
Error Estimator ◽  
Frequency Diversity ◽  
Time Frequency ◽  
Mimo Ofdm ◽  
Subcarrier Mapping

Channel estimation techniques for Multiple-input Multiple-output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) based on comb type pilot arrangement with least-square error (LSE) estimator was investigated with space-time-frequency (STF) diversity implementation. The frequency offset in OFDM effected its performance. This was mitigated with the implementation of the presented inter-carrier interference self-cancellation (ICI-SC) techniques and different space-time subcarrier mapping. STF block coding in the system exploits the spatial, temporal and frequency diversity to improve performance. Estimated channel was fed into a decoder which combined the STF decoding together with the estimated channel coefficients using LSE estimator for equalization. The performance of the system was compared by measuring the symbol error rate with a PSK-16 and PSK-32. The results show that subcarrier mapping together with ICI-SC were able to increase the system performance. Introduction of channel estimation was also able to estimate the channel coefficient at only 5dB difference with a perfectly known channel.

An improved least square channel estimation algorithm for coherent optical OFDM system

Optik ◽  
2013 ◽  
Vol 124 (23) ◽  
pp. 5937-5940 ◽  
Author(s):  
S. Zhang ◽  
C.L. Bai ◽  
Q.L. Luo ◽  
L. Huang ◽  
F.F. He
Keyword(s):  
Channel Estimation ◽  
Estimation Algorithm ◽  
Least Square ◽  
Ofdm System ◽  
Square Channel ◽  
Optical Ofdm

scholarly journals Channel Estimation in DCT-Based OFDM

2014 ◽  
Vol 2014 ◽  
pp. 1-6
Author(s):  
Yulin Wang ◽  
Gengxin Zhang ◽  
Zhidong Xie ◽  
Jing Hu
Keyword(s):  
Channel Estimation ◽  
Orthogonal Frequency Division Multiplexing ◽  
Multipath Fading ◽  
Wireless Channel ◽  
Least Square ◽  
System Throughput ◽  
Multipath Fading Channel ◽  
Channel Response ◽  
Coherent Demodulation ◽  
And Performance

This paper derives the channel estimation of a discrete cosine transform- (DCT-) based orthogonal frequency-division multiplexing (OFDM) system over a frequency-selective multipath fading channel. Channel estimation has been proved to improve system throughput and performance by allowing for coherent demodulation. Pilot-aided methods are traditionally used to learn the channel response. Least square (LS) and mean square error estimators (MMSE) are investigated. We also study a compressed sensing (CS) based channel estimation, which takes the sparse property of wireless channel into account. Simulation results have shown that the CS based channel estimation is expected to have better performance than LS. However MMSE can achieve optimal performance because of prior knowledge of the channel statistic.

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 Block-Type Pilot Arrangement with Alternating Polarity for ICI Mitigation in Mobile OFDM Systems

2013 ◽  
Vol 9 (3) ◽  
pp. 178 ◽  
Author(s):  
Titiek Suryani ◽  
Gamantyo Hendrantoro
Keyword(s):  
Channel Estimation ◽  
Doppler Shift ◽  
Channel Model ◽  
Estimation Error ◽  
Least Square ◽  
Channel Estimation Error ◽  
Piecewise Linear Approximation ◽  
Modulation Scheme ◽  
Block Type ◽  
Time Varying

Improvement on Inter Carrier Interference (ICI)mitigation techniques for OFDM caused by Doppler effectsthrough minimizing channel estimation error and decreasingchannel time varying rate is investigated. The performanceof pilot-aided channel estimation techniques depends on pilot placement and arrangement and also on the channel time varying rate. The block-type and comb-type pilot arrangements are studied through different numbers of guard bands, with or without the involvement of the Doppler shift compensation. The estimation of channel at mid-point of each OFDM symbol is derived from pilot frequencies based on the least square algorithm while the channel interpolation is done using piecewise linear approximation. For ICI mitigation technique we implement frequency domain zero forcing equalizer. We compare the performance of schemes with different pilot arrangementsand Doppler shift compensations by measuring bit error rate with QPSK as sub-channel modulation scheme and with mobileto-fixed of single ring scattering as channel model. The results are in favour of block-type pilot arrangements with alternating polarity and Doppler compensation of 0:55 times the maximum Doppler shift.

scholarly journals Analysis of channel interpolation algorithms for mobile wimax standard

2010 ◽  
Author(s):  
Nguyen Duc Quang ◽  
Luu Thanh Tra ◽  
Pham Hong Lien
Keyword(s):  
Channel Estimation ◽  
Estimation Algorithm ◽  
Least Square ◽  
Fourth Generation ◽  
Mobile Wimax ◽  
Modulation Scheme ◽  
Ieee 802.16E ◽  
Square Channel ◽  
Interpolation Algorithms ◽  
Modulation Schemes

The fourth generation (4G) wireless products are expected to be based on worldwide interoperability for microwave access (WiMAX) systems. In this paper, the issue of channel estimation in the mobile WiMAX systems (IEEE 802.16e-2005) is analyzed. We study by simulation  the  use  of  the  least  square  channel estimation  algorithm  combining  with  several modulation schemes and interpolation algorithms. The aim  is  to  choose  the  most  feasible  interpolation algorithms  for  each  modulation  scheme  of  mobile WiMAX.  The  results  show  that  the  linear  and  the cubic sub-division interpolations perform the  best and they are proposed to be used in modulation schemes.

Improved Algorithm Based on the DFT Transform Channel Estimation and Threshold Filtering

2013 ◽  
Vol 391 ◽  
pp. 536-539
Author(s):  
Chao Ma ◽  
Chun Xian Xiao ◽  
Jiang Zhu
Keyword(s):  
Channel Estimation ◽  
Impulse Response ◽  
Time Domain ◽  
Estimation Algorithm ◽  
Cyclic Prefix ◽  
Noise Variance ◽  
Traditional Algorithm ◽  
The Impact ◽  
Better Than ◽  
Improved Algorithm

In channel estimation, the complexity of the DFT-based channel estimation algorithm is lower than the MMSE algorithm, and the DFT-based algorithm performs better than the LS algorithm. However, due to that the traditional algorithms simply considered all the samples to be useful channel impulse response, ignoried the effect of noise. Therefore, the algorithm could be improved. This paper presents an improved algorithm based on twice noise estimation theory. The algorithm uses the sequence of points other than the cyclic prefix length to estimate the noise variance firstly, and then use the estimated noise variance to distinguish the noise samples within the cyclic prefix length. The computation of the new noise variance and noise mean through the new noise points as a threshold filters the impulse response of the channel in time domain and eliminates the impact of noise on the system further. The simulation result shows that the improved algorithm performs better than the traditional algorithm.

An Improved Channel Estimation Algorithm and Implementation Based on FPGA for OFDM System

2012 ◽  
Vol 500 ◽  
pp. 689-695
Author(s):  
Chang Sheng Xia ◽  
Min Shi ◽  
Li Juan Feng
Keyword(s):  
Channel Estimation ◽  
Interpolation Method ◽  
Estimation Algorithm ◽  
Linear Interpolation ◽  
Least Square ◽  
Matlab Simulation ◽  
Ofdm System ◽  
Fpga Design ◽  
Linear Interpolation Method ◽  
Frequency Domain Response

An improved FPGA implementation of channel estimation based on pilot arrangement is proposed in this paper. Typical methods are firstly investigated and compared by MATLAB simulation. The paper puts the pilots to the least square criterion to estimate the channel frequency domain response by using linear interpolation method with comb-type pilots arrangement in FPGA implement, it makes a good balance between algorithmic capability and FPGA design complexity. The simulations prove that the design can accomplish channel estimation and emendation, and it can meet the demand of the system.

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