scholarly journals Various Channel Estimation Techniques for OFDM Systems through Different Parameters

2019 ◽  
Vol 8 (12S) ◽  
pp. 999-1003
Keyword(s):  
Channel Estimation ◽  
Communication Systems ◽  
Wireless Transmission ◽  
Wireless Communication Systems ◽  
Performance Parameters ◽  
Ofdm Systems ◽  
Ofdm System ◽  
Estimation Techniques ◽  
Channel Frequency Response ◽  
Response Versus

Channel estimation in OFDM system can be performed in many ways, channel estimation is the major essential component to be calculated for the wireless communication systems (such as mobile) because these are very much effective to noise than compared to the wired communications (landlines).it has loss of data due to noise, multipath degradation, fading, etc .channel estimation is the crucial task for the effective and the reliable wireless transmission. These OFDM based systems can be improved by the pilot assisted channel estimation .As compared with the various techniques we are going to conclude that which of the available techniques are more efficient to achieve the great results. Various channel estimation techniques involved in it they are LS, LMS, RLS, MMSE, NLMS, LMMS, WLs, Sparse. It may includes the complexity of building ,effective to the noise, efficiency and comparing with many factors and probability of acquisition versus number of users are analyzed using QAM. Channel frequency response versus carrier no. and Error value versus the Sample performance after analyzing all the performance parameters we will conclude the best compared to other in all aspects. Sparse will have better performance as compared with the other six remaining channel estimations.

scholarly journals A Simple Two-Level Channel Estimation Scheme for OFDM System

2019 ◽  
Vol 8 (10) ◽  
pp. 4516-4520
Keyword(s):  
Kalman Filter ◽  
Channel Estimation ◽  
Communication Systems ◽  
Impulse Noise ◽  
Wireless Communication Systems ◽  
Delay Spread ◽  
Rate Performance ◽  
Ofdm System ◽  
Estimation Scheme ◽  
Channel Statistics

Due to its robustness to multipath delay spread and impulse noise, and also elevated spectral efficiency like characteristics, OFDM technology has been commonly adopted in contemporary wireless communication systems like LTE. The heart of an OFDM system is Channel estimator and the efficiency of channel estimation (CE) has a direct impact on the bit error rate performance of the system also the CE performance itself depends on effective estimation of fading channel hence the channel estimation problem has to be addressed. The popular LS based CE method is accepted for its simplicity but is found to be vulnerable to noise whereas the simple MMSE based CE that provides fine-tuned estimation still suffers from complexity as it depends on the knowledge of channel statistics (KCS). Hence a two level channel estimation technique that is a combination of kalman filter and thresholding scheme which denoises the LS initial estimates is proposed. The kalman filter tracks the estimates with initial data as LS estimates and threshold helps in selecting the significant data thus denoising the estimates and also filters the redundancy in estimated data. On comparing the existed CE techniques with that of the proposed scheme, the MSE performance of proposed scheme is found to be optimal and simple to that of the LMMSE technique.

scholarly journals Channel Estimation Techniques for OFDM and UFMC Systems for 5G Communications

2019 ◽  
Vol 8 (2S8) ◽  
pp. 1776-1778
Keyword(s):  
Channel Estimation ◽  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Wireless Communication Systems ◽  
Modulation Scheme ◽  
Frequency Division ◽  
Ofdm Systems ◽  
Machine Type ◽  
Machine Type Communications ◽  
Simulation Results

In this paper, pilot-assisted techniques for channel estimation (CE) are simulated for Universal Filtered Multi-Carrier (UFMC) modulation scheme. UFMC aims at replacing orthogonal frequency division multiplexing (OFDM) and improves performance and robustness in the case of timefrequency misalignment. These techniques efficiently support Internet of Things (IoT) and massive machine type communications (mMTC), which are identified as challenges for 5G wireless communication systems (WCS). Pilot-aided techniques are adopted and applied to OFDM and UFMC. Simulation results are supplemented to compare the performance of UFMC systems with conventional CP-OFDM systems.

scholarly journals Análisis de la técnica UFMC en un canal multitrayecto y usando estimación de canal

2021 ◽  
Vol 9 (17) ◽  
pp. 26-39
Author(s):  
Hugo Wladimir Iza Benítez ◽  
Diego Javier Reinoso Chisaguano
Keyword(s):  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Filter Bank ◽  
Estimation Method ◽  
Wireless Communication Systems ◽  
Ofdm Systems ◽  
Matlab Simulation ◽  
Fifth Generation ◽  
Power Spectral ◽  
Filter Bank Multicarrier

UFMC (Universal Filtered Multi-Carrier) is a novel multi-carrier transmission technique that aims to replace the OFDM (Orthogonal Frequency Division Multiplexing) modulation technique for fifth generation (5G) wireless communication systems. UFMC, being a generalization of OFDM and FBMC (Filter Bank Multicarrier), combines the advantages of these systems and at the same time avoids their main disadvantages. Using a Matlab simulation, this article presents an analysis of the robustness of UFMC against fading effects of multipath channels without using a CP (cyclic prefix). The behavior of the UFMC system is analyzed in terms of the PSD (Power Spectral Density), BER (Bit Error Rate) and MSE (Mean Square Error). The results show that UFMC reduces the out-band side lobes produced in the PSD of the processed signal. Also, it is shown that the pilot-assisted channel estimation method applied in OFDM systems can also be applied in UFMC systems.

scholarly journals Channel estimation of OFDM in C-band communication systems under different distribution conditions

2021 ◽  
Vol 23 (3) ◽  
pp. 1778
Author(s):  
Heba Abdul-Jaleel Al-Asady ◽  
Hassan Falah Fakhruldeen ◽  
Mustafa Qahtan Alsudani
Keyword(s):  
Fourier Transform ◽  
Channel Estimation ◽  
Fast Fourier Transform ◽  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Ofdm System ◽  
High Data ◽  
High Efficient

<p>Orthogonal frequency division multiplexing (OFDM) is a transmission system that uses multiple orthogonal carriers that are sent out at the same time. OFDM is a technique for mobile and wireless communication that has high-efficient frequency utilization, high data-rate transmission, simple and efficient implementation using the fast Fourier transform (FFT) and the inverse fast Fourier transform (IFFT), and reduces inter symbol interference (ISI) by inserting cyclic prefix (CP). One of the most important approaches in an OFDM system is channel estimation. In this paper, the orthogonal frequency division multiplexing system with the Rayleigh channel module is analyzed for different areas. The proposed approach used large numbers of subcarriers to transmit the signals over 64-QAM modulation with pilot add channel estimation. The accuracy of the OFDM system is shown in the measuring of the relationships of peak power to the noise ratio and bit error rate.</p>

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