Jun Heo

Korea University, Sŏul, Seoul, South Korea

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Publications (78)49.2 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: We investigate secure transmission for multiuser relay networks, where the undesired users who are not selected for data reception may overhear the source message as eavesdroppers. In this system, the secrecy performance may deteriorate as the number of users increases, since the number of eavesdroppers also increases. To address this issue, we consider a multiuser relay scheme with cooperative jamming (MUCJ). In this scheme, the desired user sends a jamming signal to the relay while the source sends its message to the relay, and then the relay amplifies and forwards the received signal to the desired user. Since the jamming can be subtracted only at the desired user, it acts as interference to prevent the eavesdroppers from intercepting the source message. We propose an optimal user selection scheme for the MUCJ, which is optimal in the sense of maximizing the secrecy rate. For the existing multiuser relay scheme (MURS) without cooperative jamming and the MUCJ, we derive the ergodic secrecy rates and analyze the asymptotic secrecy rate gains. We reveal that the ergodic secrecy rate can be increased as the number of users grows and much higher secrecy rate can be achieved by the MUCJ.
    IEEE Transactions on Wireless Communications 07/2015; 14(7):1-1. DOI:10.1109/TWC.2015.2410776 · 2.76 Impact Factor
  • Kyunghoon Kwon, Jun Heo
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    ABSTRACT: This paper presents a Rate-Compatible Block Turbo Code (RC-BTC) with increased transmission capacity. The proposed RC-BTC uses a new algorithm called information augmenting scheme, and can achieve a higher code rate than conventional one. A new Error Location Finding (ELF) Decoding Algorithm is introduced to solve the decoding problem of the information augmenting scheme. As a result, a novel error-correcting capability of the BTC-applied Chase-ELF Hybrid Decoder, combining the previous Chase–Pyndiah algorithm and the proposed ELF algorithm, is demonstrated via Monte-Carlo simulation. In addition, the proposed code maximally increases the transmission capacity with the Chase-ELF Hybrid decoder using an information augmenting scheme.
    Wireless Personal Communications 08/2014; 77(3). DOI:10.1007/s11277-014-1853-5 · 0.98 Impact Factor
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    ABSTRACT: Efficient design of device-to-device (D2D) communication calls for D2D users to propose adaptive power allocation strategy and to establish reliable communication links while protecting the QoS of cellular communications. In this paper, we consider the D2D communication as an underlay to relay-assisted cellular networks. To maximize the ergodic capacity, we derive an optimal transmission power under an average power constraint. With the derived optimal transmission power, a transmission period selection strategy for D2D communication is firstly introduced to improve reliability. We derive the outage probability in closed forms and evaluate the ergodic capacity to show performances of the proposed system. Numerical results show that the D2D system can achieve high capacity gains by flexibly allocating transmission power based on channel state information and significantly enhance reliability by selecting a transmission period, while satisfying various QoS conditions for cellular communication.
    Wireless Personal Communications 06/2014; 79(1). DOI:10.1007/s11277-014-1837-5 · 0.98 Impact Factor
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    ABSTRACT: The third generation partnership project (3GPP) and digital video broadcasting-handheld standards recommend systematic Raptor codes as application-layer forward error correction for reliable transmission of multimedia data. In all previous studies on systematic Raptor codes, equal error protection for all data was considered. However, in many applications, multimedia data requires unequal error protection (UEP) that provides different levels of protection to different parts of multimedia data. In this paper, we propose a new design method for Raptor codes that provide both UEP and systematic properties over binary erasure channels. Numerical results show that the proposed UEP design is effective for reliable multi-level protection.
    Wireless Personal Communications 04/2014; 75(4). DOI:10.1007/s11277-013-1480-6 · 0.98 Impact Factor
  • IEICE Transactions on Communications 01/2014; E97.B(6):1148-1156. DOI:10.1587/transcom.E97.B.1148 · 0.33 Impact Factor
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    ABSTRACT: In this paper, we introduce a unified framework to construct entanglement-assisted quantum error-correcting codes, including additive and nonadditive codes, based on the codeword stabilized framework on subsystems. The codeword stabilized (CWS) framework is a scheme to construct quantum error-correcting codes (QECCs) including both additive and nonadditive codes, and gives a method to construct a QECC from a classical error-correcting code in standard form. Entangled pairs of qubits (ebits) can be used to improve capacity of quantum error correction. In addition, it gives a method to overcome the dual-containing constraint. Operator quantum error correction (OQEC) gives a general framework to construct quantum error-correcting codes. We construct OQEC codes with ebits based on the CWS framework. This new scheme, entanglement-assisted operator codeword stabilized (EAOCWS) quantum codes, is the most general framework we know of to construct both additive and nonadditive codes from classical error-correcting codes. We describe the formalism of our scheme, demonstrate the construction with examples, and give several EAOCWS codes.
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    ABSTRACT: This paper provides a strategy for multihop transmission with decode-and-forward (DF) in a Poisson field of interferers. We analyze the optimal linear multihop system such as optimal resource allocation, optimal placement of the relay nodes, and optimal number of hops for multihop DF relaying which minimize their outage probability.
    IEEE Communications Letters 11/2013; 17(11):2029-2032. DOI:10.1109/LCOMM.2013.101413.131959 · 1.46 Impact Factor
  • Sungsik Yoon, Jun Heo
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    ABSTRACT: In this paper, we introduce a new error correcting protocol in quantum key distribution. With this method, leakage information during the information reconciliation is reduced and a longer key can be obtained. In order to correct errors on the quantum key, we apply the turbo codes and transmit the parity information over the quantum channel. We compare loss rate of the proposed information reconciliation method with a conventional scheme in quantum key distribution.
    ICT Convergence (ICTC), 2013 International Conference on; 01/2013
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    ABSTRACT: In this paper, a decode-and-forward cooperative interference-limited multiple relay network is considered. An efficient relay selection strategy and its performance analysis are proposed, where only the relay nodes are affected by multiple interferences. In the proposed relay selection scheme, the selected relay is not always used, depending on the power of interferences and the channel state information of all links, while the direct path between source and destination is always used. For analytical tractability the distribution of interference-limited channel is approximated as an exponential distribution with high accuracy. Analysis of cooperative networks with interference-limited relays can be performed using the approximate exponential distribution by the same methods which have been used without interferences. We derive the bit error probability and outage probability of the proposed opportunistic max-min relay selection (OMRS) scheme in independent non-identically distributed Rayleigh fading channels. Numerical results present the superiority of OMRS over the conventional relay selection scheme which always uses the selected relay path. The exactness of the approximate analysis for interference-limited relays is also shown in numerical results.
    Wireless Personal Communications 01/2013; 68(2). DOI:10.1007/s11277-011-0449-6 · 0.98 Impact Factor
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    ABSTRACT: To determine the capacity of distributed wireless networks (i.e., ad hoc networks), the random access transport capacity was proposed as the average maximum rate of successful end-to-end transmission in the distance. In this article, we consider the random access transport capacity for multihop relaying to find the end-to-end throughput of a wireless ad hoc network, where each node relays the signal using an amplify-and-forward (AF) strategy. In particular, we analyze the exact outage probability for multihop AF relaying in the presence of both co-channel interference and thermal noise, where interferers are spatially distributed following a Poisson distribution. In our numerical results, it is observed that the maximum random access transport capacity is achieved at a specific spatial density of transmitting nodes due to the throughput-reliability tradeoff as the number of transmitting nodes (=interferers) increases. We compute the optimal spatial density of transmitting nodes that maximize their random access transport capacity. As a result, we can obtain the actual random access transport capacity of multihop AF relaying and predict the maximum number of transmitting nodes per unit area to maximize their performance.
    EURASIP Journal on Wireless Communications and Networking 01/2013; 2013(1). DOI:10.1186/1687-1499-2013-104 · 0.81 Impact Factor
  • Sung-Il Kim, Jun Heo
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    ABSTRACT: In this paper, we investigate secure communication in two-hop cooperative relay network with physical layer network coding (PNC). By sending a jamming signal from the destination and exploiting the PNC at the relay, the relay decodes the exclusive-OR (XOR) performed message of the source message and the jamming. This process acts as the encryption of the source message at the relay with a random jamming sequence which can be subtracted only at the destination, so that it prevents the eavesdropper from intercepting the message. We derive the outage probability of the secure scheme with PNC and compare the performance with the cooperative scheme without jamming.
    ICT Convergence (ICTC), 2013 International Conference on; 01/2013
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    ABSTRACT: In this paper, we propose a new power optimization and transmission period selection scheme for device-to-device (D2D) communication as an underlay to cellular networks. We show that the proposed scheme can achieve performance gain by flexibly allocating transmission power based on channel state information (CSI) and significantly increase reliability by selecting a transmission period.
    ICT Convergence (ICTC), 2013 International Conference on; 01/2013
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    ABSTRACT: This paper presents an improved data hiding technique based on BCH (n,k,t ) coding. The proposed embedder hides data into a block of input data by modifying some coefficients in the block in order to null the syndrome. The proposed embedder can hide data with less computational time and less storage capacity compared to the existing methods. The complexity of the proposed method is linear while that of other methods are exponential for any block size n. Thus, it is easy to extend this method to a large n. The BCH syndrome coding for steganography is now viable ascribed to the reduced complexity and its simplicity of the proposed embedder.
    IEEE Transactions on Information Theory 12/2012; 58(12):7272-7279. DOI:10.1109/TIT.2012.2217072 · 2.65 Impact Factor
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    ABSTRACT: Codeword stabilized quantum codes provide a unified approach to constructing quantum error-correcting codes, including both additive and non-additive quantum codes. Standard codeword stabilized quantum codes encode quantum information into subspaces. The more general notion of encoding quantum information into a subsystem is known as an operator (or subsystem) quantum error correcting code. Most operator codes studied to date are based in the usual stabilizer formalism. We introduce operator quantum codes based on the codeword stabilized quantum code framework. Based on the necessary and sufficient conditions for operator quantum error correction, we derive a error correction condition for operator codeword stabilized quantum codes. Based on this condition, the word operators of a operator codeword stabilized quantum code are constructed from a set of classical binary errors induced by generators of the gauge group. We use this scheme to construct examples of both additive and non-additive codes that encode quantum information into a subsystem.
    Physical Review A 08/2012; 86(4). DOI:10.1103/PhysRevA.86.042318 · 2.99 Impact Factor
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    ABSTRACT: In this paper we design an irregular low-density parity-check (LDPC) code for multiple-input multiple-output (MIMO) systems, using a simple extrinsic information transfer (EXIT) chart method. The MIMO systems considered are the optimal maximum a posteriori probability (MAP) detector and the suboptimal minimum mean square error soft-interference cancellation (MMSE-SIC) detector. The MIMO detector and the LDPC decoder exchange soft information and form a turbo iterative receiver. The EXIT charts are used to obtain the edge degree distribution of the irregular LDPC code which is optimized for the MIMO detector. It is shown that the performance of the designed LDPC code is better than that of conventional LDPC code which was optimized for either the Additive White Gaussian Noise (AWGN) channel or the MIMO channel without an explicit consideration of the given detector structure. KeywordsLow-density parity-check (LDPC) codes–Multi-input multi-output (MIMO) detection–Iterative decoding–EXIT chart
    Wireless Personal Communications 02/2012; 62(4):923-936. DOI:10.1007/s11277-010-0101-x · 0.98 Impact Factor
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    ABSTRACT: We investigate a performance of cooperative relaying in the device-to-device (D2D) systems underlaying cellular networks while considering power constraints on the average received-interference at the evolved NodeB (eNB). Specifically, we consider the D2D communication assisted by relays using multihop decode-and-forward (DF) strategy in interference existing circumstances. In this paper, we obtain exact closed-form expression for the CDF and the PDF of the received Signal-to-Interference-plus-noise ratio (SINR) at the end user over Rayleigh flat fading channel. The end-to-end performance is investigated in terms of the maximum ergodic capacity, and the outage probability. Simulation results follow to show the performance of the system in the various propagation conditions.
    Information Theory and its Applications (ISITA), 2012 International Symposium on; 01/2012
  • Sung-Il Kim, Jun Heo
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    ABSTRACT: This paper investigates the outage performance of an amplify-and-forward (AF) relay network with varying number of relays (RN-VR). In the previous works for the analysis of multi-relay networks, the number of available relays is always assumed to be fixed. Thus, the performance and diversity of the relay network is determined by the assumed number of available relays. However, under some practical cooperative system where many users in neighboring region share a restricted number of relays, the number of available relays may change due to the preoccupied relays by other users. Therefore, the performance and diversity of the relay networks cannot be represented as the previous analysis and, thus, a different investigation of this model is needed in this case. To investigate the suggested cooperative system, occupancy of each relay is modeled as a continuous time Markov on-off process to represent the varying number of relays and provide analytical insight. Based on this theoretical approach, we explore the outage performance of an AF relay network which is called RN-VR in a practical manner.
    Personal Indoor and Mobile Radio Communications (PIMRC), 2012 IEEE 23rd International Symposium on; 01/2012
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    ABSTRACT: To account for randomly distributed nodes in a wireless ad hoc network, the transmission capacity is defined as the number of successful transmissions taking place in the network per unit area under an outage constraint. In this paper, we analyze the transmission capacity for dual-hop relaying in a wireless ad hoc network in the presence of both cochannel interference and thermal noise, where interferers are spatially distributed following a Poisson distribution. Specifically, we first present the exact outage probability for amplify-and-forward and decode-and-forward protocols in a Poisson field of interferers without neglecting noise at all nodes. We then derive the transmission capacity of such networks, which determines the maximum allowable density of transmitting nodes for each relay strategy at a specified outage probability and data rate. Numerical results demonstrate that the dual-hop relaying is still beneficial in terms of the transmission capacity in wireless ad hoc Poisson networks.
    EURASIP Journal on Wireless Communications and Networking 01/2012; 2012(1). DOI:10.1186/1687-1499-2012-58 · 0.81 Impact Factor
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    ABSTRACT: In this paper, we consider an improved transmission scheme for HDTV broadcasting services in Europe. We investigate the Forward Error Correction (FEC) algorithm in DVB-T2 standard systems and propose a new algorithm to improve the performance of the FEC scheme. The FEC of DVB-T2 transmission system is serially concatenated binary BCH code and binary Low-Density Parity Check Code (LDPC code). As we replace binary BCH code by Block Turbo Code (BTC) which is good for soft decision iterative decoding, we examine the performance enhancement by lowering the error floor. Thus we suggest BTC and LDPC concatenation for 3D HDTV transmission system and present the improved performance by Monte Carlo simulation.
    01/2012; DOI:10.1109/ICCE.2012.6161890
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    ABSTRACT: To account for randomly distributed nodes in a wireless ad hoc network, the random access transport capacity is defined as the average maximum rate of successful end-to-end transmission over some distance. In this paper, we consider a random access transport capacity for a dual-hop relaying to find the end-to-end throughput of wireless ad hoc network, where each node relays using Amplify-and-Forward (AF) strategy. In particular, we also present the exact outage probability for dualhop AF relaying in the presence of both co-channel interference and thermal noise, where interferers are spatially distributed following a Poisson distribution. Intriguingly, even though transmitting nodes increase, numerical results demonstrate that the overall throughput of dual-hop AF relaying decreases due to interference. Moreover, it is noted that the dual-hop AF relaying is still beneficial in terms of the random access transport capacity in wireless ad hoc networks.
    01/2012; DOI:10.1109/WCNC.2012.6214098

Publication Stats

288 Citations
49.20 Total Impact Points

Institutions

  • 2008–2014
    • Korea University
      • Department of Electrical Engineering
      Sŏul, Seoul, South Korea
    • LG Electronics
      Sŏul, Seoul, South Korea
  • 2004–2014
    • Konkuk University
      • Department of Electronics Engineering
      Sŏul, Seoul, South Korea
  • 2006
    • Dankook University
      Eidō, North Chungcheong, South Korea
  • 2000–2002
    • University of Southern California
      • Department of Electrical Engineering
      Los Angeles, California, United States