scholarly journals Investigations on wavelet and Fourier transform based channel estimation in MIMO-OFDM system

2018 ◽  
Vol 7 (2.21) ◽  
pp. 228
Author(s):  
B Somasekhar ◽  
Ch Mohana Krishna ◽  
Y Murty
Keyword(s):  
Fourier Transform ◽  
Channel Estimation ◽  
Discrete Fourier Transform ◽  
Fading Channels ◽  
Multipath Fading ◽  
Estimation Methods ◽  
Ofdm System ◽  
Channel Estimator ◽  
Narrow Side ◽  
Mimo Ofdm

In this paper channel estimation methods for MIMO-OFDM system are investigated based on Fourier Transform and Wavelet Transform. The channel estimation algorithm based on Discrete Fourier Transform (DFT) cause energy leakage in multipath channel with non-sample-spaced time delays. Discrete Cosine Transform (DCT) based channel estimator can mitigate the drawback of Discrete Fourier Transform based channel estimator, when the non-sample spaced path delays are available in multipath fading channels. Wavelet based systems provide better spectral efficiency because of no cyclic prefix requirement, with narrow side lobes and also exhibit improved BER performance. Simulation results reveal that the DWT based transform outperforms the conventional DFT and DCT based channel estimator in terms of bit error rate and mean square error.  

scholarly journals Channel Estimation in MIMO-OFDM System

2014 ◽  
Vol 14 (2) ◽  
pp. 97-102
Author(s):  
SR Aryal ◽  
H Dhungana
Keyword(s):  
Channel Estimation ◽  
Mean Square Error ◽  
Minimum Mean Square Error ◽  
Multipath Fading ◽  
Spatial Multiplexing ◽  
Diversity Gain ◽  
Estimation Methods ◽  
Mean Square ◽  
Ofdm System ◽  
Mimo Ofdm

There are no limit of human desire, so day by day we need much higher data speed to facilitate our need but every physical resource like frequency band, transmit signal strength are finite. Within the given limited resource, higher data speed is accomplished by new proficiency called Multiple Input Multiple Output (MIMO), Orthogonal Frequency Division Multiplexing (OFDM) system. MIMO-OFDM fulfills the high data rate requirement through spatial multiplexing gain and improved link reliability due to antenna diversity gain. With this technique, both interference reduction and maximum diversity gain are achieved by increasing number of antennae on either side. Received signal in MIMO-OFDM system is usually distorted by multipath fading. In order to recover the transmitted signal correctly, channel effect must be estimated and repaired at receiver. In this paper the performance evaluating parameter mean square error and symbol error rate of least square error, minimum mean square error and DFT based channel estimation methods are estimated and appropriate solution is recommended. Furthermore, comparison among their characteristics is simulated in MATLAB and useful conclusion is delineated. DOI: http://dx.doi.org/10.3126/njst.v14i2.10421   Nepal Journal of Science and Technology Vol. 14, No. 2 (2013) 97-102

scholarly journals Simple Channel Estimation Techniques Based on Pilot-Assistance for STBC-Based MIMO-OFDM Systems

2009 ◽  
Author(s):  
Tran Duc Tan ◽  
Ta Duc Tuyen ◽  
Trinh Anh Vu ◽  
Huynh Huu Tue
Keyword(s):  
Channel Estimation ◽  
Fading Channels ◽  
Performance Improvement ◽  
Additive Noise ◽  
Multipath Fading ◽  
Ofdm Systems ◽  
Multipath Fading Channels ◽  
Pilot Assistance ◽  
Mimo Ofdm ◽  
High Flexibility

With equipping multiple antennas at both transmitter and receiver ends, the signals in the wireless OFDM systems could be transmitted over multipath fading channels for achieving benefits and high flexibility. In this paper, we focus on MIMO-OFDM systems that simultaneously perform channel estimation in order to combat additive noise, and multipath fading. The performance improvement is confirmed by simulations. Results show that the proposed MIMOOFDM scheme is quite robust in practical environments.

An Improved DFT-Based Channel Estimation Algorithm for OFDM System on Time-Varying Multipath Fading Channels

2014 ◽  
Vol 989-994 ◽  
pp. 3786-3789 ◽  
Author(s):  
Xin Li Ma ◽  
Tong Liang Fan ◽  
Yong Feng Du
Keyword(s):  
Channel Estimation ◽  
Fading Channels ◽  
Estimation Algorithm ◽  
Multipath Fading ◽  
Statistical Information ◽  
Time Varying ◽  
Ofdm Systems ◽  
Ofdm System ◽  
Multipath Fading Channels ◽  
Suppress Noise

An improved discrete Fourier transform DFT-based channel estimation for OFDM systems is proposed. Conventional DFT-based channel estimator improved its performance by suppressing noise, but it does not completely suppress noise. In order to overcome the disadvantage, this paper proposed a gate method without requiring any channel statistical information. This method comprehensively considersthe effects of the power of the strongest path and the noises. Computer simulation demonstrates the performance of the proposed algorithms in terms of bit error rate.

scholarly journals EFFICIENT ANALYSIS OF MIMO-OFDM SYSTEM IN NAKAGAMI-m FADING CHANNEL

2016 ◽  
Vol 54 (6) ◽  
pp. 698
Author(s):  
Ho Van Cuu ◽  
Hoang Hiep Le ◽  
Nguyen Thi Thu-Hang
Keyword(s):  
Phase Shift ◽  
Fading Channels ◽  
Error Rate ◽  
Fading Channel ◽  
Orthogonal Frequency Division Multiplexing ◽  
Multipath Fading ◽  
Phase Shift Keying ◽  
Ofdm System ◽  
Shift Keying ◽  
Mimo Ofdm

Bit error rate (BER) and symbol error rate (SER) performance response fading parameter for multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) system over Nakagami-m fading channel would be provided in this study. Some channel simulations and evaluations were for 2×2 MIMO-OFDM system in which data are sent from two transmit antennas to two receive antennas. In this study, authors have used binary phase-shift keying (BPSK) and quadrature phase-shift keying (QPSK) modulation techniques to modulate the data stream. In addition, numerical results have been presented and compared for several different environmental propagations such as Nakagami-m, Rician, Rayleigh multipath fading channels, and non-fading additive white Gaussian noise (AWGN) channel. Based on such obtained presentation and comparison, the paper would discuss further about relation between value of paramater m and quality of system.

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