• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.3 s.333
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• pp.9-14
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• 2005

OFDM(Orthogonal Frequency Division Multiplexing) is widely used in wideband wireless communication systems due to its excellent performance. However, OFDM has a disadvantage of high peak-to-average power ratio and SC-FDE(Single-Carrier with Frequency-Domain Equalization) was introduced to overcome the drawback. SC-FDE is less sensitive to nonlinear power amplifiers than OFDM while its complexity and performance is comparable. This paper proposes a frequency diversity technique for single-antenna BPSK SC-FDE systems using repeated QPSK transmissions with rearranged transmission patterns.

• Journal of Communications and Networks
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• v.9 no.4
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• pp.466-472
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• 2007

Single carrier block transmission with frequency domain equalization(SC-FDE) has been shown to be a promising candidate in ultra-wideband(UWB) communications. In this paper, we analyze the performance of SC-FDE over UWB communications with channel estimation error. The probability density functions of the frequency domain minimum mean-squared error(MMSE) equalizer taps are derived in closed form. The error probabilities of single carrier block transmission with frequency domain MMSE equalization under imperfect channel estimation are presented and evaluated numerically. Compared with the simulation results, our semi-analytical analysis yields fairly accurate bit error rate performance, thus validating the use of the Gaussian approximation method in the performance analysis of the SC-FDE system with channel estimation error.

• The Journal of the Acoustical Society of Korea
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• v.26 no.6
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• pp.227-234
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• 2007

This paper describes a transmission method based on a single carrier with frequency domain equalization (SC-FDE) scheme with cyclic prefix(CP). The SC-FDE has similar features with orthogonal frequency division multiplexing(OFDM). Similar to OFDM, a SC-FDE system is computationally efficient since equalization is reformed on a block of data in the frequency domain. Especially, it has the advantage of low sensitivity to nonlinear distortion compared to OFDM. In this paper, we design a SC-FDE receiver using decision-directed method, and present simulation results.

• Journal of Communications and Networks
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• v.11 no.5
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• pp.473-479
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• 2009

Conventional frequency domain equalization (FDE) schemes were originally devised for quasi-static channels. Thus, such equalization schemes could suffer from significant performance degradation in fast-fading channels. This paper proposes a frequency domain equalization algorithm to mitigate the effect of fast time-varying fading. First, a mathematical expression is derived to quantify the total interference resulting from the time variation of the channel. Then, the proposed approach attempts to eliminate the effect of time-variations of the channel. This cancellation allows efficient use of the classical FDE structures in fast time-varying fading environments, although they are built upon the quasi-static channel model. Simulation results of bit-error-rate performance are provided to demonstrate the effectiveness of the proposed algorithm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.8
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• pp.981-987
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• 2019

In this paper, we propose a new SC-FDE (single carrier frequency domain equalization) structure to cope with narrow band interference signals or jammers and reduce pilot overhead. The conventional SC-FDE structure has a problem that the receiver performance degrades severely due to difficulty in time-domain channel estimation when narrow band jammers exist. In addition, the spectral efficiency is lowered by transmitting pilot at every SC-FDE block to estimate channel response. In order to overcome those problems, the proposed structure is devised to estimate frequency domain channel directly without time domain channel estimation. To reduce the pilot overhead, several data blocks are transmitted between two pilots. The channel estimate of each data block is found through linear interpolation of two channel estimates at two pilots. By performing frequency domain channel equalization using this channel estimate, the distortion by the channel is well compensated when narrow band jammers exist. The performance of the proposed structure is confirmed by computer simulation.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.101-102
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• 2006

Similar to Orthogonal Frequency Division Multiplexing (OFDM), a Single Carrier with Frequency Domain Equalization (SC-FDE) system is computationally efficient since equalization is performed on a block of data in the frequency domain. In coherent QAM schemes, the mean phase rotation error caused by the residual carrier frequency offset may lead to serious degradation. When the frequency equalizer is combined with the mean phase error tracking algorithm, its performance can be enhanced noticeably.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.10A
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• pp.964-971
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• 2008

This paper compares the performances of cyclic delay diversity and phase rolling techniques for SC-FDE(Single Carrier with Frequency Domain Equalization) systems with multiple transmit antennas assuming time-flat and frequency-flat channels. In OFDM(Orthogonal Frequency Division Multiplexing) systems generation of time varying channels using phase rolling can result in performance gains comparable to those of frequency-selective channels made by cyclic delay diversity However, in SC-FDE systems making time-selective channels may produce better results than creation of frequency-selective channels.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.11C
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• pp.641-648
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• 2011

Frequency domain equalization is the most promising technology that has relatively low complexity in multipath channel. A frame of single carrier system with frequency domain equalization (SC-FDE) has cyclic prefix to mitigate effect of delay spread. After synchronization and equalization procedure on the SC-FDE system, common phase offset (CPO) that can introduce performance degradation caused by phase mismatch between transmitter and receiver oscillators is remained. In this paper, common phase offset tracking in frequency domain is proposed. To track CPO, constant amplitude zero autocorrelation code sequence as training sequence is adopted. By using numerical results, performance of mean square error is evaluated. The results show that MSE of CPO has similar performance compare to the time-domain estimation and there is no need of domain conversion.

• Journal of Korea Society of Industrial Information Systems
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• v.16 no.4
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• pp.19-26
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• 2011

Relay-assisted multiple input multiple output (MIMO) technique has become a promising candidate for next generation broadband wireless communications. In this paper, we propose maximum ratio combining (MRC) minimum mean-square-error (MMSE) equalization for single carrier-frequency domain equalizer (SC-FDE) in amplify-and-forward (AF) relaying networks. The performance of SC-FDE system can be improved considerably by achieving both the diversity gain and the MMSE equalization gain when the signals from source-destination (S->D) and source-relay-destination (S->R->D) are combined and equalized by means of the MMSE criteria. We find the weighting coefficients of MRC combining and the tap coefficients of MMSE equalizer for SC-FDE in AF relaying networks. Simulation results show that the proposed relay-based system considerably outperforms the conventional SC-FDE system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.611-613
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• 2017

This paper proposes a new method to reduce the overhead by pilots for single carrier frequency domain equalization (SC-FDE) transmission. In the conventional SC-FDE transmission structure, the overhead by transmitting pilot are heavy because the pilot are transmitted at every SC-FDE block. The proposed SC-FDE structure has fewer pilots and many SC-FCE blocks are transmitted between pilots. The channel estimation and equalization is performed at the pilot period and the channels between pilots are estimated through linear interpolation. This reduces the pilot overhead by reducing the pilot transmission compared with the conventional structure, and enables reliable channel estimation and equalization.