Performance Analysis of Carrier Frequency Offset Estimation Techniques for OFDM Systems (original) (raw)
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Carrier Frequency Offset Estimation for OFDM Systems Using Time/Frequency-Domain Techniques
International Journal of Advanced Research in Computer Science and Electronics Engineering, 2012
The demand for high-speed mobile wireless communications is rapidly growing. Orthogonal Frequency Division Multiplexing (OFDM) has become a key element for achieving the high data capacity and spectral efficiency requirements for wireless communication systems because of it multicarrier modulation techniques. But its main drawback is the effect of carrier frequency offset (CFO) produced by the receiver local oscillator or by Doppler shift. This frequency offset breaks the orthogonality among the subcarriers and hence causes intercarrier interference (ICI) in the OFDM symbol, which greatly degrades the overall system performance. In this paper we will study the effects of CFO upon signal to noise ratio (SNR) for an OFDM system, and also estimate the amount of carrier frequency offset. We compare three methods to combat carrier frequency offset: Time domain CP based method, frequency domain based Moose and Classen method. The improved performance of the present scheme is confirmed through extensive MATLAB simulation results.
A Review on Carrier Frequency Offset Estimation in OFDM Systems
Journal of emerging technologies and innovative research, 2017
This paper is a review of the various techniques for carrier frequency offset (CFO) estimation in orthogonal frequency division multiplexing (OFDM). The performance of OFDM system is much sensitive to CFO, which causes inter-carrier interference (ICI). In cyclic prefix (CP) based estimation, the CFO can be estimated from the phase angle of the product of CP & corresponding end part of the OFDM symbol. In CFO estimation using training symbol, the CFO estimation range can be increased by reducing the distance between two blocks of samples for correlation. This was made possible by using training symbol that are repetitive with shorter period. Bit Error Rate vs Signal to Noise Ratio & mean square error (MSE) are the some characterization parameters of the system to observe the effects of frequency offset synchronization.
Carrier frequency offset estimation in OFDM systems
2013 IEEE CONFERENCE ON INFORMATION AND COMMUNICATION TECHNOLOGIES, 2013
This paper presents a basic useful technique for carrier frequency offset (CFO) estimation in orthogonal frequency division multiplexing (OFDM) over frequency selective fading channel. The performance of OFDM system is very sensitive to CFO, which introduces inter-carrier interference (ICI). In cyclic prefix (CP) based estimation, the CFO can be found from the phase angle of the product of CP and corresponding rear part of the OFDM symbol. In CFO estimation using training symbol, the CFO estimation range can be increased by reducing the distance between two blocks of samples for correlation. This was made possible by using training symbol that are repetitive with shorter period. An analytic expression in form of mean square error(MSE) of frequency offset synchronization is reported, and simulation results verify theoretical analysis.
International journal of engineering research and technology, 2015
Orthogonal frequency division multiplexing (OFDM) systems are very sensitive to the frequency synchronization errors in form of carrier frequency offset (CFO). CFO can lead to the Inter-Carrier interference (ICI) and also destroys the orthogonality between sub-carriers. Therefore, CFO plays a key role in Frequency synchronization. Basically for getting a good performance of OFDM, the CFO should be estimated and compensated. In this paper we investigate the algorithms for the CFO estimation in OFDM systems. Four types of estimators are investigated: cyclic prefix (CP) and Training Sequence based estimators in time domain in addition to Training Symbol based and pilot tone based estimators in frequency domain. Mean Square Error (MSE) is the comparison criteria used in studying the performance. Simulation results indicate the performance of the different estimators over both additive white Gaussian noise (AWGN) and four taps multipath fading channels. Keywords—Orthogonal frequency divi...
A novel method for the estimation of carrier frequency offset in OFDM systems
2014
In the latest development of Orthogonal Frequency Division Multiplexing (OFDM) communication system, the system performance can be distracted by the frequency offsets (FOs) which can demolish the orthogonality of the subcarriers, and hence leads to a number of impairments in the received signal, thereby making its detection incorrect. In this paper, a new threshold-based frequency offset estimation algorithm for orthogonal frequency division multiplexing (OFDM) systems is proposed. Through a detailed analysis and simulation over AWGN channel, it has been shown that the proposed method shows good performance i.e. it offers low error variance as the SNR (signal to noise ratio) increases. © 2014 Elixir All rights reserved ARTICLE INF O Articl e h istory: Received: 8 January 2014; Received in revised form: 20 May 2014; Accepted: 30 May 2014;
OFDM Carrier Frequency Offset Estimation Methods With Improved Performance
IEEE Transactions on Broadcasting, 2000
Orthogonal frequency division multiplexing (OFDM) systems are highly sensitive to carrier frequency offset and symbol timing error. This paper deals with estimation method of integer frequency offset (IFO) without the aid of pilot symbols. The proposed IFO estimator exploits two consecutive identical OFDM data symbols with only change of phase. In order to improve the accuracy of the IFO estimator, receive diversity is adopted. To demonstrate the efficiency of the proposed IFO estimators, comparisons are made with other existing estimators in terms of error performance, estimation range, and complexity.
Carrier Frequency Offset (CFO) Estimation Methods, A Comparative Study
2015
Estimation of Carrier Frequency Offset (CFO) is the fundamental problem of OFDM systems. CFO can be estimated using either time domain or frequency domain methods. A comparative study among different methods of carrier frequency offset estimation in OFDM systems is presented. We consider two techniques in time domain, namely; the Cyclic Prefix (CP) method and the Training Sequence Method. In addition two techniques in frequency domain are considered, namely; Training Symbol method and Pilot Method. Mean square Error (MSE) is the comparison criteria used in the study. Simulation results show that the CFO estimation methods in frequency domain have better performance than CFO estimation methods in time domain, in terms of mean square error (MSE). It is shown that, the pilot tone method outperforms the cyclic prefix method by 7dB and the training sequence with two identical blocks by 10dB. The pilot tone method outperforms the symbol based method by approximately 2dB. The comparison re...
A frequency domain method for the carrier frequency offset estimation in OFDM systems
2013 8th International Symposium on Image and Signal Processing and Analysis (ISPA), 2013
The rapid growth and development of wireless data transmission brings new trends, challenges and constraints in the telecommunications field. Novel multicarrier techniques are proposed to meet these requirements. The orthogonal frequency division multiplexing (OFDM) is an attractive technique that achieves high data rate and high spectral efficiency and, at the same time, suppresses multipath fading in wireless communications. However, the OFDM is very sensitive to mobility of the transmitter, receiver or surrounding objects. The mobility produces interchannel interference which significantly deteriorates transmission performance. The interchannel interference suppression represent research challenge. Carrier frequency offset (CFO) estimation and its compensation represent a way to improve OFDM system's performance. In this paper, we consider CFO estimation in the frequency domain by using well known iterative algorithms for precise estimation of spectral peak's central peak frequency. Simulations show that the proposed method outperforms standard CFO estimation methods in terms of accuracy. In simulations, both AWGN channel and multipath channel are considered.
Carrier Frequency Offset Estimation for OFDM Systems Over Mobile Radio Channels
IEEE Transactions on Vehicular Technology, 2010
In this paper, a new technique is proposed for blind estimation of carrier frequency offset (CFO) in wireless orthogonal frequency-division multiplexing (OFDM) systems with constant-modulus constellations. The proposed scheme is based on the assumption that the channel slowly changes in the time domain with respect to the OFDM symbol duration. As a consequence, the channel effect on a given subcarrier in two consecutive OFDM symbols is approximately the same. Based on this assumption, a cost function is derived such that the power difference between all subcarriers in two consecutive OFDM symbols is minimized. Using Monte Carlo simulation, we demonstrate that the proposed scheme has superior performance in both static and time-varying frequency-selective fading channels. The proposed system can rapidly and accurately estimate the CFO using only three trial values, given that the CFO is less than half of the subcarriers' frequency spacing.