Amnart Boonkajay

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Joint transmit/receive frequency-domain equalization based on minimum mean-square error criterion (joint Tx/Rx MMSE-FDE) is a promising frequency-domainbased technique suppressing inter-symbol interference (ISI) in broadband single-carrier (SC) transmission. However, it changes the frequency-domain spectrum shape and hence increases the peak-to-average(More)
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 time-domain spread spectrum (TDSS). However, its wider transmission bandwidth leads to low spectrum efficiency, implying that a(More)
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 error based frequency-domain equalization (MMSE-FDE) at the receiver can combat the problem of inter-symbol interference (ISI)(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)
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 filtering is widely used, where the filter shape is controlled by the roll-off factor  from 0 to 1. Nyquist filtering with =1(More)
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 of analog circuit and baseband unit. On the other hand, the energy consumption of power amplifier (PA) highly depends on(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)
Transmit filtering, transmit equalization, precoding, or power allocation increases the peak-to-average power ratio (PAPR) of transmit single-carrier (SC) signal due to change in frequency-domain spectrum. Recently, we proposed a frequency-domain based selected mapping (FD-SLM) for suppressing the increased PAPR introduced by the transmit frequency-domain(More)