Kwanwoong Ryu

Electronics and Telecommunications Research Institute | ETRI · Broadcasting and Telecommunications Media Research Laboratory

We propose a very fast-convergence joint iterative detection and decoding (JIDD) scheme for channel-coded sparse code multiple access (SCMA). In the conventional JIDD, all users’ channel decoding iterations are performed in parallel after all users’ variable nodes in the SCMA factor graph are updated. The proposed JIDD scheme, however, slices all c...

In this paper, we propose an emergency wake-up alert system (EWAS) for providing accurate and rapid emergency information. The proposed system can provide an emergency wake-up alert service without an additional frequency allotment by utilizing the guard band of the Advanced Television Systems Committee (ATSC) Terrestrial Digital Television (DTV) s...

In this paper, we design a frame structure of the wake-up system using DTV excess bandwidth for emergency alerting based on the Advanced Television Systems Committee (ATSC) terrestrial DTV system. The proposed frame structure of that system is based on the FSK modulation for indoor reception in receiver. Laboratory test and simulation results show...

Recently, the transition from analog television (ATV) to digital television (DTV) has been progressing in terrestrial broadcasting. Therefore, wake-up system for emergency alerting in DTV is needed. In this paper, we design wake-up system using DTV guard band for emergency alerting based on the Advanced Television Systems Committee (ATSC) terrestri...

Recently, the digital television transition from analog television to digital television has been progressing in terrestrial broadcasting. As a result of the DTV transition, additional reassignments and deployments of TV White spaces (TVWS) caused by co-channel interference (CCI) were needed. In this paper, we investigate the TVWS caused by CCI usi...

This paper analyzes the capacity and the coverage of the augmented data transmission (ADT). The ADT system can offer an additional data rate of up to a few Mbps based on hierarchical modulation within the 6-MHz DTV broadcasting channel without requiring any additional RF spectrum. The analysis results show that the spectral efficiency of ADT system...

In this paper, we present a new Multi-Carrier Code-selective Code Division Multiple Access System (MC CS-CDMA) with frequency repetition. The code selection process enables the proposed scheme to decrease the number of subcarriers for the same transmission data rate and total bandwidth as conventional MC DS-CDMA. The remaining bandwidth can be used...

Multicarrier direct sequence code division multiple access (MC DS-CDMA) is an attractive technique for achieving high data rate transmission. This is valid regardless of whether or not the potentially large peak-to-average power ratio (PAPR) is an important factor for its application. On the other hand, code select CDMA (CS-CDMA) is an attractive t...

In this letter, we evaluate the system performance of a space-time block coded (STBC) multicarrier (MC) DS-CDMA system over a time selective fading channel, with imperfect channel knowledge. The average bit error rate impairment due to imperfect channel information is investigated by taking into account the effect of the STBC position. We consider...

This letter investigates the effects of the Space-Time Block Code (STBC) transmitter diversity and Time Switched Transmitter Diversity (TSTD) schemes while simultaneously considering the time diversity effect derived from Chase combining and the frequency diversity effect for downlink Spread OFDM packet wireless access in a broadband multipath fadi...

In this letter, we propose a quasi-orthogonal space-time-frequency (QOSTF) block coded orthogonal frequency division multiplexing (OFDM) that can achieve full symbol rate with four transmit antennas. Since the proposed QOSTF-OFDM cannot achieve full diversity, we use a diversity advantage collection with zero forcing (DAC-ZF) decoder to compensate...

In this paper, we propose a full rate quasi-orthogonal space-time-frequency block coded orthogonal frequency division multiplexing(QOSTF-OFDM) that can achieve full symbol rate with four transmit antennas. Sincr: the proposed QOSTF-OFDM can not achieve full diversity, we use diversity advantage collection with zero forcing (DAC-ZF) decoder to compe...

In this paper, we present a new multicarrier CDMA system which we call multicarrier code select CDMA (MC CS-CDMA). We compare the performance of both MC CS-CDMA in various parallel input bits M of SCB (each group) and the MC DS-CDMA by the probability of error over a frequency-selective Rayleigh fading channel in the presence of the same data rate...

An application of orthogonal frequency division multiplexing (OFDM) signal for high-bit rate transmission is limited by the high peak-to-average power ration (PAR). Recently, two techniques for improving the PAR statistics of OFDM signal have been proposed: selective mapping (SLM) and partial transmit sequences (PTS) methods. However, the complexit...

In this paper, we propose a new multi-carrier system which called multi-carrier code-selected code-division multiple access (MC CS-CDMA) by combining the CS-CDMA and multi-carrier modulation to provide better performance than conventional multi-carrier system. The PAR (peak-to-average power ratio) and the bandwidth of transmitted signal spectrum ar...

In this paper, we propose a PAR (Peak to Average power Ratio) reduction algorithm by using an ABC (Adaptive Block Coding) technique. The problem of PAR due to each sub-carrier's overlap phenomenon in OFDM (Orthogonal Frequency Division Multiplexing) system causes the increasing the complexity of the A/D converter in the transmitter and the reducing...

In this paper, we propose a new multicarrier system, which we called multicarrier code-selected code-division multiple access(MC CS/CDMA). The results are compared with MC DS/CDMA in a Multipath fading channel. The PAR(peak-to-average power ratio) and the bandwidth of transmitted signal spectrum are compared with those of a conventional multicarrie...