Daesik Hong

Yonsei University, Sŏul, Seoul, South Korea

Are you Daesik Hong?

Claim your profile

Publications (313)263.8 Total impact

  • Joonki Kim · Seokjung Kim · Jonghyun Bang · Daesik Hong

    No preview · Article · Jan 2016 · IEEE Communications Letters
  • Seunglae Kam · Dongkyu Kim · Haesoon Lee · Daesik Hong
    [Show abstract] [Hide abstract]
    ABSTRACT: Our investigation focuses on the performance of full-duplex systems where both nodes simultaneously exchange their signals using a single spectrum for two-way communication. To maximize the achievable sum rate (ASR) for full-duplex systems in multispectrum environments, we address a new selection strategy that considers the channel state of both nodes. The ASR for a multispectral bidirectional full-duplex (M-BFD) system is obtained using the proposed selection strategy and compared with conventional multispectral bidirectional half-duplex (M-BHD) systems. We derive the ASR as closed-form expressions and quantify the effect of selection diversity on the ASRs for M-BFD and M-BHD systems. In addition, we present practical-case Monte Carlo simulation results by considering the effects of self-interference (SI) and channel correlation. The numerical results show that the ASR gain for M-BFD is larger than that for M-BHD.
    No preview · Article · Aug 2015 · IEEE Transactions on Vehicular Technology
  • [Show abstract] [Hide abstract]
    ABSTRACT: 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. Therefore, to mitigate the interference and improve the sum capacity, we additionally propose a set selection algorithm and power control scheme. The set selection algorithm, which selects 2N users based on orthogonality and gain-difference between their channels, reduces the interference between users. Furthermore, the power control scheme can maximize the sum capacity with ensuring minimum target rate. Numerical results show that the proposed system improves the sum capacity over that of the conventional orthogonal multiple access (OMA) system.
    No preview · Article · Jul 2015
  • Jonghyun Bang · Jemin Lee · Seokjung Kim · Daesik Hong
    [Show abstract] [Hide abstract]
    ABSTRACT: Cognitive radio networks using relays have been introduced to enhance secondary network performance by having secondary users (SUs) transmit in two hops. This paper develops a framework for a random cognitive relay network (RCRN) where the primary, secondary, and relay nodes are randomly distributed according to Poisson point processes (PPPs) to investigate the effect of the random nature of the relays on secondary outage performance. We first derive the optimal relay location in terms of the outage probability of the secondary network. In addition, we provide the outage probability of the RCRN based on the optimal relay selection strategy that compares the instantaneous channel state information (CSI) of all relays. We then propose an efficient relay selection strategy that reduces the selection complexity and the feedback burden by limiting candidate relays to those located close to the optimal relay location. This paper sheds new light on the design of an efficient RCRN with respect to elements such as the effects of network parameters and the candidate relay set size on the RCRN outage probability.
    No preview · Article · Mar 2015 · IEEE Transactions on Wireless Communications
  • Dongkyu Kim · Haesoon Lee · Daesik Hong
    [Show abstract] [Hide abstract]
    ABSTRACT: In-band full-duplex (IBFD) transmission represents an attractive option for increasing the throughput of wireless communication systems. A key challenge for IBFD transmission is reducing self-interference. Fortunately, the power associated with residual self-interference can be effectively canceled for feasible IBFD transmission with combinations of various advanced passive, analog, and digital self-interference cancellation schemes. In this survey paper, we first review the basic concepts of IBFD transmission with shared and separated antennas and advanced self-interference cancellation schemes. Furthermore, we also discuss the effects of IBFD transmission on system performance in various networks such as bidirectional, relay, and cellular topology networks. This survey covers a wide array of technologies that have been proposed in the literature as feasible for IBFD transmission and evaluates the performance of the IBFD systems compared to conventional half-duplex transmission in connection with theoretical aspects such as the achievable sum rate, network capacity, system reliability, and so on. We also discuss the research challenges and opportunities associated with the design and analysis of IBFD systems in a variety of network topologies. This work also explores the development of MAC protocols for an IBFD system in both infrastructure-based and ad hoc networks. Finally, we conclude our survey by reviewing the advantages of IBFD transmission when applied for different purposes, such as spectrum sensing, network secrecy, and wireless power transfer.
    No preview · Article · Jan 2015 · IEEE Communications Surveys & Tutorials
  • Hyungjong Kim · Hanho Wang · Daesik Hong

    No preview · Article · Oct 2014
  • Youngju Kim · Hano Wang · Daesik Hong

    No preview · Article · Oct 2014
  • [Show abstract] [Hide abstract]
    ABSTRACT: We propose a new method for full-duplex self-interference cancellation. The proposed scheme uses a precoder to align the self-interference channel with orthogonal direction of detection axis. The simulation result shows that the proposed RP-SIC enhances the average throughput of user equipment compared to the conventional scheme in high residual self-interference region.
    No preview · Conference Paper · Sep 2014
  • Dongkyu Kim · Sungsoo Park · Hyungsik Ju · Daesik Hong
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper investigates the network capacity of bidirectional communication systems based on full-duplex transmission in ad hoc networks while satisfying both the delay and target outage constraints. Bidirectional full-duplex transmission (BFD) has been proposed as a way to increase the system performance of two-way communications with multiple antennas. This type of system enables simultaneous exchange of data between two nodes via the bidirectional use of spatial resources. As the node density is increased to improve network capacity, however, the network performance decreases because of the simultaneous transmissions of adjacent pairwise interferers. To overcome this capacity degradation, we apply an automatic repeat request (ARQ) protocol to two-way communications. We then extend the analysis of the transmission capacity (TC) to account for packet retransmissions within the maximum allowed delay while satisfying the target outage constraint for two extreme cases (high mobility and static). After determining the optimized maximum number of packet retransmissions, the network capacity of the BFD system is then investigated as a function of the effective node density, node mobility, and required delay and target outage constraints. We can conclude that the benefits for TC obtained through full-duplex transmission and packet retransmission by an ARQ protocol outweigh the increase in interference caused by the bidirectional use of spatial resources and packet retransmissions.
    No preview · Article · Sep 2014 · IEEE Transactions on Vehicular Technology
  • Haesoon Lee · Dongkyu Kim · Jinmin Kim · Daesik Hong

    No preview · Article · Aug 2014
  • Hanho Wang · Daesik Hong

    No preview · Article · Aug 2014
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, we consider a full-duplex amplify-and-forward (AF) relaying with guaranteeing quality of service (QoS). In order to evaluate the QoS guaranteeing ability of FDR, we derive the effective capacity with considering residual self-interference. Based on the analysis and numerical results, it is verified that the stringent QoS constraint degrades effective capacity performance of full-duplex relay (FDR) more severely than that of half-duplex relay. The simulation results also show that the better link quality at S-R link is required in order to guarantee QoS constraint at FDR.
    No preview · Conference Paper · Jun 2014
  • [Show abstract] [Hide abstract]
    ABSTRACT: 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 without the intrinsic interference. In order to satisfy the suggested orthogonality conditions, we perform a kind of block interleaving for the odd-numbered sub-carrier filtering. The receiver structure is the counterpart to the transmitter. Numerical results showed that the proposed FBMC-QAM system has almost the same bit error rate (BER) performance compared to the FBMC-OQAM and the orthogonal frequency division multiplexing (OFDM) system. with the proposed FBMC-QAM, multiple-input multiple-output transmission schemes and channel estimation schemes can be utilized similarly as in OFDM.
    No preview · Conference Paper · Jun 2014
  • Wonsuk Chung · Sungsoo Park · Sungmook Lim · Daesik Hong
    [Show abstract] [Hide abstract]
    ABSTRACT: We consider an energy-harvesting cognitive radio system where the secondary transmitter harvests energy. This system operates under an energy causality constraint mandating that the average energy consumption must not exceed the average harvested energy, and a collision constraint mandating the protection of the primary system. The purpose of this paper is to identify the optimal pairing of the sensing duration and the energy detector's sensing threshold in order to maximize the average throughput of the secondary network. Since the sensing duration and sensing threshold are intertwined with the energy causality constraint, they need to be redesigned with the purpose of conserving energy in mind. Hence, the sensing duration must be shorter while still satisfying the collision constraint. The numerical results show that the optimal sensing duration is determined based on which constraint, collision or energy causality, needs to have priority. In addition, the simulation results show a pairing of the optimal sensing duration and sensing threshold provided by the coordination between the two constraints, which gives insight into how to design them.
    No preview · Article · May 2014 · IEEE Transactions on Wireless Communications
  • [Show abstract] [Hide abstract]
    ABSTRACT: In cognitive radio, spectrum sensing is used to find the white spectrum or protect the primary user from interference caused by the secondary user (SU). There are two conventional spectrum sensing approaches: quiet and active. However, these conventional approaches have several problems. In quiet sensing, the quiet period degrades the SU capacity. With active sensing, the SU capacity is also degraded by the need for additional resource consumption and the mismatch in feedback information. In order to mitigate these problems, the structure of simultaneous PU sensing and data transmission is introduced. This structure is equipped with antenna isolation and self-interference cancellation in which the communication and the sensing radios are already assumed to be significantly isolated. This approach is designed so that the SU transmitter can sense PU signals and transmit data signals at the same time by dividing its spatial resources. Expanding on this work, we propose a concept of "TranSensing" which adaptively uses spatial resource according to the surrounding environments. To effectively use TranSensing, we propose a two-stage algorithm (TSA). Finally, the impact of residual interference on TranSensing is investigated. Simulation results show that TranSensing with TSA enhances the SU capacity over the conventional quiet or active sensing.
    No preview · Article · Apr 2014 · IEEE Transactions on Wireless Communications
  • Sungsoo Park · Daesik Hong
    [Show abstract] [Hide abstract]
    ABSTRACT: We consider energy harvesting cognitive radio networks to improve both energy efficiency and spectral efficiency. The goal of this paper is to analyze the theoretically achievable throughput of the secondary transmitter, which harvests energy from ambient sources or wireless power transfer systems while opportunistically accessing the spectrum licensed to the primary network. By modeling the temporal correlation of the primary traffic according to a time-homogeneous discrete Markov process, we derive the upper bound on the achievable throughput as a function of the energy arrival rate, the temporal correlation of the primary traffic, and the detection threshold for a spectrum sensor. The optimal detection threshold is then derived to maximize the upper bound on the achievable throughput under an energy causality constraint and a collision constraint. The energy causality constraint mandates that the total consumed energy should not exceed the total harvested energy, while the collision constraint is required to protect the primary network from secondary transmission. Analytical results show the temporal correlation of the primary traffic to enable efficient usage of the harvested energy by preventing the secondary transmitter from accessing the spectrum that may be occupied by the primary network.
    No preview · Article · Feb 2014 · IEEE Transactions on Wireless Communications
  • Gosan Noh · Sungmook Lim · Yosub Park · Jihaeng Heo · Daesik Hong
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper investigates the effect of the transmit power fluctuation of the primary user on the ergodic capacity of the secondary user in a spectrum sharing environment. Considering an average received-power constraint at the primary user receiver, we derive the closed-form expression for the ergodic capacity of the secondary user and the average received-power assuming Rayleigh fading channels. Numerical results show that the transmit power fluctuation can enhance the ergodic capacity of the secondary user if the secondary user properly control its transmit power so as to fully exploit the transmit power fluctuation.
    No preview · Conference Paper · Feb 2014
  • [Show abstract] [Hide abstract]
    ABSTRACT: 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 system are changed uniformly. In addition, we demonstrate that the proposed system can improve the quality of service for cell-edge users while guaranteeing user fairness.
    No preview · Conference Paper · Feb 2014
  • Sungsoo Park · Daesik Hong
    [Show abstract] [Hide abstract]
    ABSTRACT: We consider energy harvesting cognitive radio networks in which a secondary transmitter harvests energy from ambient sources or wireless power transfer systems while opportunistically accessing the spectrum licensed to the primary network. The primary traffic is modeled as a time-homogeneous discrete Markov process, and the secondary transmitter may not be able to operate continuously due to sporadic and unstable energy sources. At the beginning of each time slot, the secondary transmitter thus needs to determine whether to remain idle so as to conserve energy, or to execute spectrum sensing to acquire knowledge of the current spectrum occupancy state. It also needs to configure the spectrum sensor detection threshold to achieve an effective tradeoff between false alarms and misdetections. This sequential decision-making, done to maximize the expected total throughput, requires the joint design of a spectrum sensing policy and a detection threshold under the energy causality and collision constraints. We formulate this stochastic optimization problem as a constrained partially observable Markov decision process (POMDP), and then convert it to a computationally tractable unconstrained POMDP. Numerical results show that the proposed approach enables efficient usage of the harvested energy by exploiting the temporal correlation of the primary traffic.
    No preview · Article · Dec 2013 · IEEE Transactions on Wireless Communications
  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper investigates an attempt to improve reliability in two-way communication through the bi-directional use of spatial resources when time selectivity exists and instantaneous channel information is not available at the transmitter. The system, which uses spatial resources bi-directionally and employs beamforming, is called a 'bi-directional beamforming (BBF)' system. The use of full bandwidth and the reciprocity between time and frequency allow the BBF system to reduce the symbol duration. Focusing on this reduction in symbol duration, we propose a transmit antenna-switched receive diversity for BBF (TAS-BBF) scheme designed to improve reliability in time selective environments. The resulting TAS-BBF scheme with N antennas can achieve diversity order of 2(N-1) in fast fading environments without channel state information at the transmitter, whereas conventional schemes are only able to achieve a diversity order of N in this environment.
    No preview · Conference Paper · Nov 2013

Publication Stats

4k Citations
263.80 Total Impact Points

Institutions

  • 1995-2015
    • Yonsei University
      • Department of Electrical and Electronic Engineering
      Sŏul, Seoul, South Korea
  • 2011
    • University of Texas at Austin
      • Department of Electrical & Computer Engineering
      Austin, Texas, United States
    • Princeton University
      • Department of Electrical Engineering
      Princeton, New Jersey, United States
  • 2007
    • Myongji University
      • Department of Information and Communication Engineering
      Sŏul, Seoul, South Korea
  • 2004
    • Samsung Advanced Institute of Technology
      Usan-ri, Gyeonggi Province, South Korea
  • 2002
    • Tsinghua University
      Peping, Beijing, China
    • Huazhong University of Science and Technology
      Wu-han-shih, Hubei, China
    • Oklahoma State University - Stillwater
      Stillwater, Oklahoma, United States
  • 2000
    • The Seoul Institute
      Sŏul, Seoul, South Korea