Amnart Boonkajay

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In this paper, a DFT-based frequency-domain spread spectrum (FDSS) technique for SC transmission is introduced. The transmitted data is initially transformed to frequency-domain signal by using DFT. Frequency-domain spreading can achieve large frequency diversity gain through joint frequency-domain equalization (FDE) and spectrum combining. Performance of(More)
—Single-carrier transmission is a promising transmission technique due to its low peak-to-average power ratio (PAPR) property compared to multicarrier transmission, and using frequency-domain equalization (FDE) at the receiving side also mitigate the adverse effect of channel frequency-selectivity. An introduction of transmit filter can improve the system(More)
— Frequency-domain equalization (FDE) based on minimum mean square error (MMSE) criterion significantly improves the bit error rate (BER) performance of single-carrier (SC) transmission by suppressing the channel frequency-selectivity. Partial response (PR) filtering, e.g., duobinary PR filtering, achieves higher spectral efficiency by permitting certain(More)
This article is a technical report without peer review, and its polished and/or extended version may be published elsewhere. Abstract A modification of transmit filtering in single-carrier (SC) transmission contributes to an improvement of system performance in terms of peak-to-average power ratio (PAPR) and bit error rate (BER). Using minimum mean-square(More)
This article is a technical report without peer review, and its polished and/or extended version may be published elsewhere. Abstract The authors have proposed a frequency-domain single-carrier spread spectrum (SC-FDSS) transmission technique, which achieves better bit-error rate (BER) and better power amplifier-dependent energy efficiency comparing with(More)
This article is a technical report without peer review, and its polished and/or extended version may be published elsewhere. Abstract Single-carrier (SC) transmission is a transmission equipped with frequency-domain equalization (FDE) is suitable for uplink transmission because of its low peak-to-average power ratio (PAPR) property. Square-root Nyquist(More)
This article is a technical report without peer review, and its polished and/or extended version may be published elsewhere. Abstract Energy efficiency (EE), which is defined as a ratio of spectrum efficiency (SE) to power consumption, is a key performance metric in mobile communication system. The signal waveform has little influence on energy consumption(More)
We consider a downlink OFDMA subcarrier allocation problem where the allocation algorithms are gradient-based but only CSI for some subet of subcarriers from each user is available at the transmitter. We propose an iterative version of gradient-based OFDMA subcarrier allocation schedulers which performs better than the standard non-iterative gradient-based(More)