Sooyong Choi's research while affiliated with Yonsei University and other places

Publications (171)

Preprint
In this study, a novel coding scheme called highdensity coding based on high-density codebooks using a genetic local search algorithm is proposed. The high-density codebook maximizes the energy transfer capability by maximizing the ratio of 1 in the codebook while satisfying the conditions of a codeword with length n, a codebook with 2k codewords,...
Article
This work studies cooperative inference of deep neural networks (DNNs), in which the inference process is performed in a cooperative manner by an edge device and an edge server. In particular, a practical noisy wireless channel between the edge device and the edge server is considered in this work, unlike the previous works which only considered id...
Article
In the fifth-generation (5G) high-speed train (HST) system operating in the millimeter-wave (mmWave) band, a much higher Doppler shift occurs. Doppler shift severely degrades reception performance in orthogonal frequency division multiplexing (OFDM)-based wireless communication systems. The performance of the Doppler shift estimator is directly rel...
Article
Full-text available
A circular convolution-based filter bank multi-carrier system adopting quadrature amplitude modulation (CQAM-FBMC) that utilizes partial response signaling (PRS), referred to as the PRS-CQAM-FBMC system, is proposed and analyzed. The proposed PRS-CQAM-FBMC system has fully overlapped FBMC symbols without the time shifts and the transition time thro...
Article
Full-text available
The concept of a large intelligent surface (LIS) has recently emerged as a promising wireless communication paradigm that can exploit the entire surface of man-made structures for transmitting and receiving information. An LIS is expected to go beyond massive multiple-input multiple-output (MIMO) system, insofar as the desired channel can be modele...
Article
Full-text available
Full-spreading non-orthogonal multiple access (FS-NOMA) is one category of the candidate technologies designed to support massive connectivity in wireless communication systems. Before it can handle the massive volume of user connections, it is important for the FS-NOMA to develop a receiver that successfully decodes target data from non-orthogonal...
Article
A new precoder design scheme, called the signal-controlled-leakage-noise ratio (SCLNR), is proposed. The proposed SCLNR precoder is designed to enhance the data rate and harvesting energy simultaneously. Specifically, the proposed SCLNR precoder is designed to increase the leakage signal toward energy users and decrease leakage signal toward data u...
Article
Full-text available
A dispersed signal transmission and reception scheme is proposed to cope with selfinterference (SI) and inter-user interference (IUI) in full-duplex systems. During transmission, each identical signal of each transmitter is transmitted in multiple time slots after being multiplied by the transmission coefficients corresponding to the individual tim...
Article
Full-text available
Large intelligent surfaces (LISs) have been recently proposed as an effective wireless communication solution that can leverage antenna arrays deployed on the entirety of man-made structures such as walls. An LIS can provide space-intensive and reliable communication, enabling the desired wireless channel to exhibit a perfect line-of-sight. However...
Article
This paper proposes two link adaptation strategies for IEEE 802.15.4 wireless personal area networks (WPANs), using a multi-rate signaling set. In the proposed link adaptation strategies, the most adequate modulation and coding scheme (MCS) satisfying the target bit error rate (BER) of the end device is selected based on the signal-to-interference-...
Preprint
Full-text available
Large intelligent surfaces (LISs) have been recently proposed as an effective wireless communication solution that can leverage antenna arrays deployed on the entirety of man-made structures such as walls. An LIS can provide space-intensive and reliable communication, enabling the desired wireless channel to exhibit a perfect line-of-sight. However...
Article
In this paper, we study the channel state information (CSI) feedback based on the deep autoencoder (AE) considering the feedback errors and feedback delay in the frequency division duplex (FDD) massive multiple-input multiple-output (MIMO) system. We construct the deep AE by modeling the CSI feedback process, which involves feedback transmission er...
Article
Increasing areal density in bit patterned media recording systems increases the 2-D interference from the adjacent islands in the down-track and cross-track directions. Also, nonlinear effects due to the track mis-registration (TMR) and media noise become severe as the areal density increases and degrade the bit error rate (BER) performance. In thi...
Conference Paper
Full-text available
Large intelligent surfaces (LISs) are a promising wireless communication paradigm that can exploit the entire surface of man-made structures for transmitting and receiving information. To understand the fundamental performance benefits of LISs, it is imperative to analyze their achievable data rate, under practical LIS environments and limitations....
Preprint
Full-text available
The concept of a large intelligent surface (LIS) has recently emerged as a promising wireless communication paradigm that can exploit the entire surface of man-made structures for transmitting and receiving information. An LIS is expected to go beyond massive multiple-input multiple-output (MIMO) system, insofar as the desired channel can be modele...
Article
This paper proposes a new generalized frequency division multiplexing (GFDM) system that eliminates the effects of intrinsic interference and makes it possible to insert a pilot for channel estimation without interference. We express intersubsymbol interference (ISI) and inter-carrier interference (ICI), which represent the intrinsic interference i...
Article
In this paper, we propose a linearly processed filterbank multicarrier (LP-FBMC) system which employs a faster than Nyquist signaling to remove residual intrinsic interferences. We represent the FBMC transceiver in a matrix form and then apply singular value decomposition (SVD)-based linear transformation in order to convert the overlapped FBMC dat...
Article
Full-text available
In this study, the scaling laws of optimal training lengths were investigated for time-division duplexing massive multiple-input-multiple-output systems. First, the generalized asymptotic achievable rate was derived by taking into account both uplink and downlink training. From the general form, the achievable rates of zero-forcing (ZF) and matched...
Article
This paper proposes a new Orthogonal Frequency Division Multiplexing (OFDM)-based waveform, called Time Spread-Windowed OFDM (TS-W-OFDM). TS-W-OFDM applies a windowing procedure to improve spectral efficiency and a time spreading method to create a block signal structure. Numerical results show that TS-W-OFDM has higher spectral efficiency and near...
Article
In this paper, we consider a new interference problem caused by idle small cells which have no associated user equipment (UE) in ultra-dense small cell long-term evolution (LTE) networks. Specifically, we investigate the effect of idle small cells on the signal to interference and noise ratio (SINR) of the cell-specific reference signal (CRS) and t...
Article
In this paper, we investigate the outage probability of a multiuser multiple-input multiple-output (MU-MIMO) system in the heterogeneous network (HetNet) in the presence of unpredictable interference from coexisting ad-hoc systems. In order to achieve multiuser diversity gain, the MU-MIMO system requires feedback carrying the signal-to-interference...
Article
An enhanced 2/3 four-ary modulation code using soft-decision Viterbi decoding is proposed for four-level holographic data storage systems. While the previous four-ary modulation codes focus on preventing maximum two-dimensional intersymbol interference patterns, the proposed four-ary modulation code aims at maximizing the coding gains for better bi...
Article
A two-dimensional (2D) partial response maximum likelihood (PRML) detection scheme for misalignment compensation for holographic data storage systems is proposed. In the proposed detection scheme, a misalignment estimator and a predetermined table are added to the conventional 2D PRML scheme to estimate and reflect the effect of misalignment in the...
Article
A statistical beamforming (SBF) scheme based on the effective channel gain (ECG) is proposed for spatially correlated massive multiple-input multiple-output systems. The proposed SBF scheme consists of outer and inner precoders. The outer precoder is designed to eliminate multiuser interference based on the correlation matrix of downlink channel. T...
Article
This paper proposes a new multi-carrier system, called orthogonal code-based block transmission (OCBT). OCBT applies a time-spreading method with an orthogonal code to have a block signal structure and a windowing procedure to reduce the out-of-band (OOB) radiation. The proposed OCBT can transmit the quadrature amplitude modulation (QAM) signals to...
Article
This paper analyzes the ratio of transmit antennas to receive antennas at the base station (BS) in full-duplex multiuser multiple-input-multiple-output (MU-MIMO) systems with large-array BS and half-duplex multiantenna users. We consider a full-duplex BS with a block diagonalization (BD) precoder for downlink transmission and a BD receive filter fo...
Article
Full-text available
In this paper, we consider multiuser massive multiple-input and multiple-output (MIMO) system where multiusers simultaneously utilize massive antennas of base station (BS). With a downlink frame structure considering pilot signals, we derive the ergodic cell capacity based on zero-forcing beamforming (ZFBF) technique. This paper proves that the erg...
Article
In this paper, we propose a new sequence generation methodology to make a constant amplitude zero autocorrelation (CAZAC) preamble available in offset Quadrature Amplitude Modulation-based filter bank multicarrier (FBMC) synchronization. The role of the new sequence is to compensate the filtering and symbol overlap of the FBMC structure so as to fi...
Conference Paper
This paper proposes a subframe shift method to provide the full-duplex operation for the full-duplex base station (BS) in the current time-division long term evolution (TD-LTE) systems. For the full-duplex operation using the proposed subframe shift, we also propose a frame structure for the simultaneous transmission and reception of full-duplex BS...
Article
A filter-bank multicarrier–quadrature amplitude modulation (FBMC-QAM) system with two prototype filters for transmitting QAM symbol is proposed, and the orthogonality conditions for the FBMC-QAM system without the intrinsic interference is derived. The proposed transmitter performs the individual filtering for the even and odd-numbered sub-carrier...
Conference Paper
In this paper, we evaluate the performance of hetero-geneous networks with physical cell identity (cell ID) operation of small cells. We consider the two cell ID modes standardized in long term evolution-advanced (LTE-A) systems, the single cell ID mode and the different cell ID mode. First, we investigate the user equipment (UE) throughput accordi...
Article
A multi-stage turbo equalization scheme based on the bit-level combining (BLC) is proposed for multiple-input multipleoutput (MIMO) systems with hybrid automatic repeat request (HARQ). In the proposed multi-stage turbo equalization scheme, the minimum mean-square-error equalizer at each iteration calculates the extrinsic log-likelihood ratios for t...
Article
The performance of symbol-level combining (SLC) and bit-level combining (BLC) in multiple-input multipleoutput (MIMO) multiple automatic repeat request (ARQ) systems is investigated. Considering the zero-forcing (ZF) detection under the assumption of perfect packet elimination for SLC, the two performance characteristics of Chase combining (CC) wit...
Article
An ordered successive interference cancellation (OSIC) scheme based on combined post-processing signal-to-interference-plus-noise ratio (PSINR) is proposed for multiple-input multiple-output (MIMO) systems with retransmission. For the OSIC procedures at the current transmission round, instead of reusing the PSINRs and decision statistics calculated...
Article
In this letter, we evaluate the performances of both GOOK and GFSK de/modulation techniques which are candidates for ULP communications in WPAN systems. For the performance evaluation, we define the system model for each of GOOK and GFSK de/modulations and perform computer simulations based on the proposed models. From the computer simulations, we...
Article
In this letter, we investigate the performance analysis of massive MIMO systems using MRT and ZF precodings according to the number of DoF. We analyze the ergodic received SINRs with MRT and ZF precodings as closed-forms over the number of DoF normalized by the number of antennas. In simulation results, we verify the analyzed results and observe th...
Article
This paper proposes an iterative equalizer based on Kalman filtering and smoothing (IEKFS) for multiple-input multiple-output inter-symbol interference (MIMO-ISI) channels. A state-space model with a priori information and the corresponding Kalman filtering (KF) and Kalman smoothing (KS) operations are developed. The KF operations perform a linear...
Article
In this letter, a QR decomposition based sequential BP detection scheme is proposed for MIMO systems. The proposed scheme performs the sequential updates from the observation node having the smallest degree among all the observation nodes. Our simulation results verify that the proposed scheme achieves an improved error performance with a significa...
Article
In this letter, a parity check based iterative IC scheme is proposed for LDPC coded MIMO systems. After the decoding procedures in each iteration of the proposed scheme, each decoded codeword is utilized for the IC procedures only when the ratio of the check nodes satisfying the parity check equations to the total number of check nodes is not small...
Conference Paper
In this paper, we propose a uplink (UL) non-orthogonal multiple access (NOMA) systems equipped with multiple antennas to enhance the sum capacity of UL. In the proposed UL NOMA system, a base station (BS) with N antennas can support 2N users by sharing the space resource. However, sharing the space resource leads to interference between users. Ther...
Article
In this paper, we consider IEEE 802.15.4 based wireless body area sensor networks (WBASN) in the healthcare environment. Connectivity is a critical constraint in the healthcare environment. In particular, disconnection from a sensor hub is a significant problem that leads to sensor node orphaning. To address this, we propose to use a sub hub design...
Article
A QR decomposition aided belief propagation (QR-BP) detector for multiple-input multiple-output (MIMO) systems is proposed. Before the iterative message passing process, linear transformation is performed by using the unitary matrix obtained from the QR decomposition of the original MIMO channel matrix. Then, the original MIMO channel matrix is rep...
Article
In this paper, multiuser channel quality indicator (MU-CQI) prediction based on channel quantization error feedback is proposed for massive multiple-input multiple-output (MIMO) systems. Basically, CQI reporting in the practical systems is performed based on the single user (SU) MIMO transmission mode to keep low feedback overhead and computational...
Article
The signaling of the healthcare applications needs the error performance and the multiple data rate for different target rates of various bio-signals. In this paper, we propose a link adaptation strategy on the multi-rate modulation set for IEEE 802.15.4 wireless personal area networks (WPANs). The protocol stack made by the network simulator OPNET...
Article
We examine small cell deployment strategies in two- tier cellular networks. Specifically, we propose a joint interference and load deployment (JD) strategy, reflecting a realistic interference environment and traffic load. In this JD, the location of a small base station (s-BS) is sequentially decided in greedy manner by exploiting both the spatial...
Article
Full-text available
In this letter, the joint mode selection and resource allocation method is proposed for D2D communication underlaying OFDMA based cellular networks. In the proposed scheme, D2D mode possible region is determined which satisfies QoS. Then we solve the optimization problem utilizing primal-dual algorithm. The proposed scheme shows better performance...
Article
In this letter, an MMSE based continuous turbo equalizer is proposed for MIMO-HARQ systems. In the proposed scheme, the soft information from the reception process for the previous transmission is reutilized at the initialization of the reception process for the next transmission to enhance the decoding convergence speed. Simulation results verify...
Article
Full-text available
This paper analyzes the power allocation scheme to maximize the sum-rate for heterogeneous networks based on asynchronous time division duplex. We consider heterogeneous networks where a small cell exists in the macro cell coverage and the small cell and the macro cell share the same time-frequency resources. We formulate the optimization problem w...
Article
In this letter, an MMSE based iterative soft decision interference cancellation scheme for massive MIMO systems is proposed. To reduce the complexity, the proposed scheme uses the Sherman-Morrison-Woodbury formula to compute the entire MMSE filtering vectors in one iteration by one matrix inverse operation. Simulation results show that the proposed...
Conference Paper
A filter-bank multicarrier - quadrature amplitude modulation (FBMC-QAM) system with two prototype filters for transmitting QAM signal is proposed. The proposed transmitter performs separate filtering for the even-numbered sub-carrier symbols and the odd-numbered sub-carrier symbols. We derive the orthogonality conditions for a FBMC-QAM system witho...
Conference Paper
In this paper, we study the effective small-cell deployment scenarios to improve the system performance. We consider three deployment strategies - the random deployment, the deployment for the worst-performance user, and the cell-edge deployment [1]. From the system level simulation results, we suggest the effective small-cell deployment strategy i...
Article
A new read channel architecture achieving diversity effects for bit patterned magnetic recording is proposed in this paper. In the proposed channel architecture, a new channel model generating several different channels for the desired symbols and the diversity achieving detection schemes are proposed to obtain performance gains with a simple struc...
Conference Paper
In this paper, we propose a load balancing and a dynamic overlay clustering procedures including the fusion procedure. The proposed load balancing gets some loss for the throughput of the overall system but it improves the throughput of the cell-edge users. Through the simulations, we verify that the load and the number of users of the proposed sys...
Conference Paper
In this paper, we propose a non-orthogonal multiple access-based multiuser beamforming (NOMA-BF) system designed to enhance the sum capacity. In the proposed NOMA-BF system, a single BF vector is shared by two users, so that the number of supportable users can be increased. However, sharing a BF vector leads to interference from other beams as well...
Conference Paper
This paper investigates a dynamic spectrum access (DSA) scheme for low power wireless sensor networks (WSN) in an open spectrum where multiple systems coexist and interfere with each other. Low transmission power and a simple communication protocol are significant obstacles to the operation of low power WSN in the open spectrum. As a result, availa...
Conference Paper
There are two important factors for the nodes of Wireless Body Area Network (WBAN): the lasting lifetime and the low loss of significant biometric data. Therefore, the stabilities of both the data queue and the energy queue are an important point on the WBAN nodes. In this paper, Minimum Distance Adaptive Allocation (MDAA) is proposed which is an a...
Conference Paper
This paper analyzes the pilot power ratio (PPR) in multiuser multiple-input multiple-output (MU-MIMO) systems with a large number of receive antennas (M) at the base station (BS). We consider zero-forcing based MU-MIMO orthogonal frequency division multiplexing (OFDM) systems. Based on the deterministic uplink sum-rate approximation for imperfect c...
Article
In this paper, we analyze a performance of multiuser massive multiple-input and multiple-output (MIMO) system. We derive the ergodic cell capacity based on a downlink frame structure and analyze the ergodic cell capacity with respect to the number of base station (BS) antennas and the number of users. This paper shows that the ergodic cell capacity...
Article
The optimal number of users achieving the maximum sum throughput is analyzed in zero-forcing (ZF) based multiuser multiple-input multiple-output (MIMO) systems with a large number of base station (BS) antennas. By utilizing deterministic ergodic sum rates for the ZF-beamforming (ZF-BF) and ZF-receiver (ZF-R) with a large number of BS antennas [1],...
Article
Full-text available
This paper proposes an energy-efficient mode selection and power allocation scheme in device-to-device (D2D) communication system as an underlay coexistence with cellular networks. We analyze the energy efficiency which is defined as the summation of the energy efficiencies for all devices. The proposed scheme consists of two steps. First, we calcu...
Article
Cell-to-cell interference compensation schemes using reduced symbol pattern of interfering cells for multilevel cell (MLC) NAND flash memory are proposed in this paper. The proposed schemes consist of three procedures, estimation of cell-to-cell interference, compensation for ce