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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal DOI :
Electronics and Telecommunications Research Institute
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Volume & Issues
Volume 37, Issue 6 - Dec 2015
Volume 37, Issue 5 - Oct 2015
Volume 37, Issue 4 - Aug 2015
Volume 37, Issue 3 - May 2015
Volume 37, Issue 2 - Apr 2015
Volume 37, Issue 1 - Feb 2015
Selecting the target year
IDNet: Beyond All-IP Network
Jung, Heeyoung ; Lim, Wan-Seon ; Hong, Jungha ; Hur, Cinyoung ; Lee, Joo-Chul ; You, Taewan ; Eun, Jeesook ; Kwak, Byeongok ; Kim, Jeonghwan ; Jeon, Hae Sook ; Kim, Tae Hwan ; Chun, Woojik ;
ETRI Journal, volume 37, issue 5, 2015, Pages 833~844
DOI : 10.4218/etrij.15.2415.0045
Recently, new network systems have begun to emerge (for instance, 5G, IoT, and ICN) that require capabilities beyond that provided by existing IP networking. To fulfill the requirements, some new networking technologies are being proposed. The promising approach of the new networking technology is to try to overcome the architectural limitations of IP networking by adopting an identifier (ID)-based networking concept in which communication objects are identified independently from a specific location and mechanism. However, we note that existing ID-based networking proposals only partially meet the requirements of emerging and future networks. This paper proposes a new ID-based networking architecture and mechanisms, named IDNet, to meet all of the requirements of emerging and future networks. IDNet is designed with four major functional blocks-routing, forwarding, mapping system, and application interface. For the proof of concept, we develop numeric models for IDNet and implement a prototype of IDNet.
Dynamic Resource Adjustment for Coexistence of LAA and Wi-Fi in 5 GHz Unlicensed Bands
Choi, Jihoon ; Kim, Eunkyung ; Chang, Sungcheol ;
ETRI Journal, volume 37, issue 5, 2015, Pages 845~855
DOI : 10.4218/etrij.15.2415.0033
To enable the coexistence of Licensed Assisted Access (LAA) and Wi-Fi in 5 GHz unlicensed bands, a new channel access mechanism is proposed. Accounting for the fairness between LAA and Wi-Fi, the proposed mechanism finds the optimal transmission time ratio by adaptively adjusting the transmission durations for LAA and Wi-Fi. In addition, we propose a new analytical model for the distributed coordination function of IEEE 802.11 through some modifications of conventional analytical models for saturation and non-saturation loads. By computing the activity ratio of Wi-Fi, the proposed analytical model is able to control the time ratio between LAA and Wi-Fi, which is required for practical implementation of the proposed access mechanism. Through numerical simulations, the proposed channel access mechanism is compared with conventional methods in terms of throughput and utility.
Mobile Small Cells for Further Enhanced 5G Heterogeneous Networks
Lee, Choong-Hee ; Lee, Sung-Hyung ; Go, Kwang-Chun ; Oh, Sung-Min ; Shin, Jae Sheung ; Kim, Jae-Hyun ;
ETRI Journal, volume 37, issue 5, 2015, Pages 856~866
DOI : 10.4218/etrij.15.2415.0022
A heterogeneous network (HetNet) is a network topology composed by deploying multiple HetNets under the coverage of macro cells (MCs). It can improve network throughput, extend cell coverage, and offload network traffic; for example, the network traffic of a 5G mobile communications network. A HetNet involves a mix of radio technologies and various cell types working together seamlessly. In a HetNet, coordination between MCs and small cells (SCs) has a positive impact on the performance of the networks contained within, and consequently on the overall user experience. Therefore, to improve user-perceived service quality, HetNets require high-efficiency network protocols and enhanced radio technologies. In this paper, we introduce a 5G HetNet comprised of MCs and both fixed and mobile SCs (mSCs). The featured mSCs can be mounted on a car, bus, or train and have different characteristics to fixed SCs (fSCs). In this paper, we address the technical challenges related to mSCs. In addition, we analyze the network performance under two HetNet scenarios-MCs and fSCs, and MCs and mSCs.
Efficient Interference Control Technology for Vehicular Moving Networks
Oh, Sung-Min ; Lee, Changhee ; Lee, Jeong-Hwan ; Park, Ae-Soon ; Shin, Jae Sheung ;
ETRI Journal, volume 37, issue 5, 2015, Pages 867~876
DOI : 10.4218/etrij.15.2415.0030
This paper proposes an efficient interference control scheme for vehicular moving networks. The features of the proposed scheme are as follows: radio resources are separated into two resource groups to avoid interference between the cellular and vehicle-to-vehicle (V2V) links; V2V links are able to share the same radio resources for an improvement in the resource efficiency; and vehicles can adaptively adjust their transmission power according to the interference among the V2V links (based on the distributed power control (DPC) scheme derived using the network utility maximization method). The DPC scheme, which is the main feature of the proposed scheme, can improve both the reliability and data rate of a V2V link. Simulation results show that the DPC scheme improves the average signal-to-interference-plus-noise ratio of V2V links by more than 4 dB, and the sum data rate of the V2V links by 15% and 137% compared with conventional schemes.
3GPP LTE-Assisted Wi-Fi-Direct: Trial Implementation of Live D2D Technology
Pyattaev, Alexander ; Hosek, Jiri ; Johnsson, Kerstin ; Krkos, Radko ; Gerasimenko, Mikhail ; Masek, Pavel ; Ometov, Aleksandr ; Andreev, Sergey ; Sedy, Jakub ; Novotny, Vit ; Koucheryavy, Yevgeni ;
ETRI Journal, volume 37, issue 5, 2015, Pages 877~887
DOI : 10.4218/etrij.15.2415.0003
This paper is a first-hand summary on our comprehensive live trial of cellular-assisted device-to-device (D2D) communications currently being ratified by the standards community for next-generation mobile broadband networks. In our test implementation, we employ a full-featured 3GPP LTE network deployment and augment it with all necessary support to provide realtime D2D connectivity over emerging Wi-Fi-Direct (WFD) technology. As a result, our LTE-assisted WFD D2D system enjoys the required flexibility while meeting the existing standards in every feasible detail. Further, this paper provides an account on the extensive measurement campaign conducted with our implementation. The resulting real-world measurements from this campaign quantify the numerical effects of D2D functionality on the resultant system performance. Consequently, they shed light on the general applicability of LTE-assisted WFD solutions and associated operational ranges.
Near-Optimal Algorithm for Group Scheduling in OBS Networks
Nhat, Vo Viet Minh ; Quoc, Nguyen Hong ; Son, Nguyen Hoang ;
ETRI Journal, volume 37, issue 5, 2015, Pages 888~897
DOI : 10.4218/etrij.15.2415.0019
Group scheduling is an operation whereby control packets arriving in a time slot schedule their bursts simultaneously. Normally, those bursts that are of the same wavelength are scheduled on the same channel. In cases where the support of full wavelength converters is available, such scheduling can be performed on multiple channels for those bursts that are of an arbitrary wavelength. This paper presents a new algorithm for group scheduling on multiple channels. In our approach, to reach a near-optimal schedule, a maximum-weight clique needs to be determined; thus, we propose an additional algorithm for this purpose. Analysis and simulation results indicate that an optimal schedule is almost attainable, while the complexity of computation and that of implementation are reduced.
Joint Beamforming and Jamming for Physical Layer Security
Myung, Jungho ; Heo, Hwanjo ; Park, Jongdae ;
ETRI Journal, volume 37, issue 5, 2015, Pages 898~905
DOI : 10.4218/etrij.15.2415.0002
In this paper, we consider a joint beamforming and jamming design to enhance physical layer security against potential multiple eavesdroppers in a multiple-input and single-output cellular broadcast channel. With perfect channel state information at the base station, we propose various design approaches to improve the secrecy of the target user. Among the proposed approaches, the combined beamforming of maximum ratio transmission and zero-forcing transmission with a combination of maximum ratio jamming and zero-forcing jamming (MRT + ZFT with MRJ + ZFJ) shows the best security performance because it utilizes the full transmit antenna dimensions for beamforming and jamming with an efficient power allocation. The simulation results show that the secrecy rate of this particular proposed approach is better than the rates of the considered conventional approaches with quality-of-service and outage probability constraints.
Adaptive Techniques for Joint Optimization of XTC and DFE Loop Gain in High-Speed I/O
Oh, Taehyoun ; Harjani, Ramesh ;
ETRI Journal, volume 37, issue 5, 2015, Pages 906~916
DOI : 10.4218/etrij.15.0114.0306
High-speed I/O channels require adaptive techniques to optimize the settings for filter tap weights at decision feedback equalization (DFE) read channels to compensate for channel inter-symbol interference (ISI) and crosstalk from multiple adjacent channels. Both ISI and crosstalk tend to vary with channel length, process, and temperature variations. Individually optimizing parameters such as those just mentioned leads to suboptimal solutions. We propose a joint optimization technique for crosstalk cancellation (XTC) at DFE to compensate for both ISI and XTC in high-speed I/O channels. The technique is used to compensate for between 15.7 dB and 19.7 dB of channel loss combined with a variety of crosstalk strengths from
adaptively, where the transmit non-return-to-zero signal amplitude is a constant
Optimal Admission Control and State Space Reduction in Two-Class Preemptive Loss Systems
Kim, Bara ; Ko, Sung-Seok ;
ETRI Journal, volume 37, issue 5, 2015, Pages 917~921
DOI : 10.4218/etrij.15.0114.0348
We consider a multiserver system with two classes of customers with preemption, which is a widely used system in the analysis of cognitive radio networks. It is known that the optimal admission control for this system is of threshold type. We express the expected total discounted profit using the total number of customers, thus reducing the stochastic optimization problem with a two-dimensional state space to a problem with a one-dimensional birth-and-death structure. An efficient algorithm is proposed for the calculation of the expected total discounted profit.
Reducing PAPR of SC-FDMA Signals through Simple Amplitude Predistortion
Xia, Yujie ; Ji, Jinwei ;
ETRI Journal, volume 37, issue 5, 2015, Pages 922~928
DOI : 10.4218/etrij.15.0114.1194
A novel peak-to-average power ratio (PAPR) reduction method is proposed for single-carrier frequency-division multiple access (SC-FDMA) signals. The proposed method deliberately distorts the amplitude values of a few of the complex modulated symbols that cause peaks beyond a predetermined threshold in the samples of the output signal. The method then marks the location indices of the distorted symbols by using a pilot block at the transmitter without transmitting side information. At the receiver, the method is then able to recover the distorted amplitude values through the marked location indices. Computer simulation results show that when compared to conventional SC-FDMA signals, the proposed scheme can effectively reduce the PAPR of SC-FDMA signals with asymptotically consistent bit error rate (BER) performance.
Conception and Performance Analysis of Efficient CDMA-Based Full-Duplex Anti-collision Scheme
Cao, Xiaohua ; Li, Tiffany ;
ETRI Journal, volume 37, issue 5, 2015, Pages 929~939
DOI : 10.4218/etrij.15.0114.0375
Ultra-high-frequency radio-frequency identification (UHF RFID) is widely applied in different industries. The Frame Slotted ALOHA in EPC C1G2 suffers severe collisions that limit the efficiency of tag recognition. An efficient full-duplex anti-collision scheme is proposed to reduce the rate of collision by coordinating the transmitting process of CDMA UWB uplink and UHF downlink. The relevant mathematical models are built to analyze the performance of the proposed scheme. Through simulation, some important findings are gained. The maximum number of identified tags in one slot is g/e (g is the number of PN codes and e is Euler's constant) when the number of tags is equal to mg (m is the number of slots). Unlike the Frame Slotted ALOHA, even if the frame size is small and the number of tags is large, there aren't too many collisions if the number of PN codes is large enough. Our approach with 7-bit Gold codes, 15-bit Gold codes, or 31-bit Gold codes operates 1.4 times, 1.7 times, or 3 times faster than the CDMA Slotted ALOHA, respectively, and 14.5 times, 16.2 times, or 18.5 times faster than the EPC C1 G2 system, respectively. More than 2,000 tags can be processed within 300 ms in our approach.
Frame Synchronization Algorithm for LDPC Coded Burst Systems
Man, Xin ; Zhai, Haitao ; Zhang, Eryang ;
ETRI Journal, volume 37, issue 5, 2015, Pages 940~944
DOI : 10.4218/etrij.15.0113.0514
We present a frame synchronization algorithm for lowdensity parity-check (LDPC) coded burst transmissions, which combines a conventional pilots-assisted frame synchronization algorithm and a code-aided algorithm based on the mean magnitude of the soft outputs from the LDPC decoder. With moderate computational complexity, the proposed algorithm is more efficient in bandwidth than conventional pilots-assisted algorithms. When compared with other code-aided algorithms, the proposed algorithm offers a better trade-off between complexity and performance. Simulation results in the case of an 8-PSK system with (1944, 972) LDPC code show that the proposed algorithm can achieve a performance equivalent to that of the perfect frame synchronization, with a bandwidth efficiency loss of 0.06 dB due to the use of pilot symbols.
Analysis of Novel Approach to Design of Ultra-wide Stopband Microstrip Low-Pass Filter Using Modified U-Shaped Resonator
Karimi, Gholamreza ; Lalbakhsh, Ali ; Dehghani, Khatereh ; Siahkamari, Hesam ;
ETRI Journal, volume 37, issue 5, 2015, Pages 945~950
DOI : 10.4218/etrij.15.0114.0188
A novel microstrip low-pass filter is presented to achieve an ultra-wide stopband with 11 harmonic suppression and very sharp skirt characteristics. The filter is composed of a modified U-shaped resonator (which creates two fully adjustable transmission zeroes), a T-shaped resonator (which determines a cut-off frequency), and four radial stubs (which provide a wider stopband). The operating mechanism of the filter is investigated based on a proposed equivalent-circuit model, and the role of each section of the proposed filter in creating null points is theoretically discussed in detail. The presented filter with 3 dB cut-off frequency (
) has been fabricated and measured. Results show that a relative stopband bandwidth of 164% (referred to as a 22 dB suppression) is obtained while achieving a high figure-of-merit of 15,221.
Electrothermal Analysis for Super-Junction TMOSFET with Temperature Sensor
Lho, Young Hwan ; Yang, Yil-Suk ;
ETRI Journal, volume 37, issue 5, 2015, Pages 951~960
DOI : 10.4218/etrij.15.0115.0226
For a conventional power metal-oxide-semiconductor field-effect transistor (MOSFET), there is a trade-off between specific on-state resistance and breakdown voltage. To overcome this trade-off, a super-junction trench MOSFET (TMOSFET) structure is suggested; within this structure, the ability to sense the temperature distribution of the TMOSFET is very important since heat is generated in the junction area, thus affecting its reliability. Generally, there are two types of temperature-sensing structures-diode and resistive. In this paper, a diode-type temperature-sensing structure for a TMOSFET is designed for a brushless direct current motor with on-resistance of
. The temperature distribution for an ultra-low on-resistance power MOSFET has been analyzed for various bonding schemes. The multi-bonding and stripe bonding cases show a maximum temperature that is lower than that for the single-bonding case. It is shown that the metal resistance at the source area is non-negligible and should therefore be considered depending on the application for current driving capability.
250 mV Supply Voltage Digital Low-Dropout Regulator Using Fast Current Tracking Scheme
Oh, Jae-Mun ; Yang, Byung-Do ; Kang, Hyeong-Ju ; Kim, Yeong-Seuk ; Choi, Ho-Yong ; Jung, Woo-Sung ;
ETRI Journal, volume 37, issue 5, 2015, Pages 961~971
DOI : 10.4218/etrij.15.0114.0985
This paper proposes a 250 mV supply voltage digital low-dropout (LDO) regulator. The proposed LDO regulator reduces the supply voltage to 250 mV by implementing with all digital circuits in a
CMOS process. The fast current tracking scheme achieves the fast settling time of the output voltage by eliminating the ringing problem. The over-voltage and under-voltage detection circuits decrease the overshoot and undershoot voltages by changing the switch array current rapidly. The switch bias circuit reduces the size of the current switch array to 1/3, which applies a forward body bias voltage at low supply voltage. The fabricated LDO regulator worked at 0.25 V to 1.2 V supply voltage. It achieved 250 mV supply voltage and 220 mV output voltage with 99.5% current efficiency and 8 mV ripple voltage at
Accurate Tunable-Gain 1/x Circuit Using Capacitor Charging Scheme
Yang, Byung-Do ; Heo, Seo Weon ;
ETRI Journal, volume 37, issue 5, 2015, Pages 972~978
DOI : 10.4218/etrij.15.0114.0577
This paper proposes an accurate tunable-gain 1/x circuit. The output voltage of the 1/x circuit is generated by using a capacitor charging time that is inversely proportional to the input voltage. The output voltage is independent of the process parameters, because the output voltage depends on the ratios of the capacitors, resistors, and current mirrors. The voltage gain of the 1/x circuit is tuned by a 10-bit digital code. The 1/x circuit was fabricated using a
CMOS process. Its core area is
), and it consumes
. Its error is within 1.7% at
to 1 V.
Constructions and Properties of General (k, n) Block-Based Progressive Visual Cryptography
Yang, Ching-Nung ; Wu, Chih-Cheng ; Lin, Yi-Chin ; Kim, Cheonshik ;
ETRI Journal, volume 37, issue 5, 2015, Pages 979~989
DOI : 10.4218/etrij.15.0114.0327
Recently, Hou and others introduced a (2, n) block-based progressive visual cryptographic scheme (BPVCS) in which image blocks can be gradually recovered step by step. In Hou and others' (2, n)-BPVCS, a secret image is subdivided into n non-overlapping image blocks. When t (
) participants stack their shadow images, all the image blocks associated with these t participants will be recovered. However, Hou and others' scheme is only a simple 2-out-of-n case. In this paper, we discuss a general (k, n)-BPVCS for any k and n. Our main contribution is to give two constructions (Construction 1 and Construction 2) of this general (k, n)-BPVCS. Also, we theoretically prove that both constructions satisfy a threshold property and progressive recovery of the proposed (k, n)-BPVCS. For k = 2, Construction 1 is reduced to Hou and others' (2, n)-BPVCS.
Reversible Binary Image Watermarking Method Using Overlapping Pattern Substitution
Dong, Keming ; Kim, Hyoung Joong ; Choi, Yong Soo ; Joo, Sang Hyun ; Chung, Byung Ho ;
ETRI Journal, volume 37, issue 5, 2015, Pages 990~1000
DOI : 10.4218/etrij.15.0114.1058
This paper presents an overlapping pattern substitution (PS) method. The original overlapping PS method as a reversible data hiding scheme works well with only four pattern pairs among fifteen possible such pairs. This paper generalizes the original PS method so that it will work well with an optimal pair from among the fifteen possible pattern pairs. To implement such an overlapping PS method, changeable and embeddable patterns are first defined. A class map is virtually constructed to identify the changeable and embeddable pairs. The run-lengths between consecutive least probable patterns are recorded. Experiments show that an implementation of our overlapping PS method works well with any possible type of pairs. Comparison results show that the proposed method achieves more embedding capacity, a higher PSNR value, and less human visual distortion for a given embedding payload.
Static Dalvik Bytecode Optimization for Android Applications
Kim, Jeehong ; Kim, Inhyeok ; Min, Changwoo ; Jun, Hyung Kook ; Lee, Soo Hyung ; Kim, Won-Tae ; Eom, Young Ik ;
ETRI Journal, volume 37, issue 5, 2015, Pages 1001~1011
DOI : 10.4218/etrij.15.0114.0036
Since just-in-time (JIT) has considerable overhead to detect hot spots and compile them at runtime, using sophisticated optimization techniques for embedded devices means that any resulting performance improvements will be limited. In this paper, we introduce a novel static Dalvik bytecode optimization framework, as a complementary compilation of the Dalvik virtual machine, to improve the performance of Android applications. Our system generates optimized Dalvik bytecodes by using Low Level Virtual Machine (LLVM). A major obstacle in using LLVM for optimizing Dalvik bytecodes is determining how to handle the high-level language features of the Dalvik bytecode in LLVM IR and how to optimize LLVM IR conforming to the language information of the Dalvik bytecode. To this end, we annotate the high-level language features of Dalvik bytecode to LLVM IR and successfully optimize Dalvik bytecodes through instruction selection processes. Our experimental results show that our system with JIT improves the performance of Android applications by up to 6.08 times, and surpasses JIT by up to 4.34 times.
Conditional Re-encoding Method for Cryptanalysis-Resistant White-Box AES
Lee, Seungkwang ; Choi, Dooho ; Choi, Yong-Je ;
ETRI Journal, volume 37, issue 5, 2015, Pages 1012~1022
DOI : 10.4218/etrij.15.0114.0025
Conventional cryptographic algorithms are not sufficient to protect secret keys and data in white-box environments, where an attacker has full visibility and control over an executing software code. For this reason, cryptographic algorithms have been redesigned to be resistant to white-box attacks. The first white-box AES (WB-AES) implementation was thought to provide reliable security in that all brute force attacks are infeasible even in white-box environments; however, this proved not to be the case. In particular, Billet and others presented a cryptanalysis of WB-AES with 230 time complexity, and Michiels and others generalized it for all substitution-linear transformation ciphers. Recently, a collision-based cryptanalysis was also reported. In this paper, we revisit Chow and others's first WB-AES implementation and present a conditional re-encoding method for cryptanalysis protection. The experimental results show that there is approximately a 57% increase in the memory requirement and a 20% increase in execution speed.
Infrared Target Extraction Using Weighted Information Entropy and Adaptive Opening Filter
Bae, Tae Wuk ; Kim, Hwi Gang ; Kim, Young Choon ; Ahn, Sang Ho ;
ETRI Journal, volume 37, issue 5, 2015, Pages 1023~1031
DOI : 10.4218/etrij.15.0114.0118
In infrared (IR) images, near targets have a transient distribution at the boundary region, as opposed to a steady one at the inner region. Based on this fact, this paper proposes a novel IR target extraction method that uses both a weighted information entropy (WIE) and an adaptive opening filter to extract near finely shaped targets in IR images. Firstly, the boundary region of a target is detected using a local variance WIE of an original image. Next, a coarse target region is estimated via a labeling process used on the boundary region of the target. From the estimated coarse target region, a fine target shape is extracted by means of an opening filter having an adaptive structure element. The size of the structure element is decided in accordance with the width information of the target boundary and mean WIE values of windows of varying size. Our experimental results show that the proposed method obtains a better extraction performance than existing algorithms.
Co-Pilot Agent for Vehicle/Driver Cooperative and Autonomous Driving
Noh, Samyeul ; Park, Byungjae ; An, Kyounghwan ; Koo, Yongbon ; Han, Wooyong ;
ETRI Journal, volume 37, issue 5, 2015, Pages 1032~1043
DOI : 10.4218/etrij.15.0114.0095
ETRI's Co-Pilot project is aimed at the development of an automated vehicle that cooperates with a driver and interacts with other vehicles on the road while obeying traffic rules without collisions. This paper presents a core block within the Co-Pilot system; the block is named "Co-Pilot agent" and consists of several main modules, such as road map generation, decision-making, and trajectory generation. The road map generation builds road map data to provide enhanced and detailed map data. The decision-making, designed to serve situation assessment and behavior planning, evaluates a collision risk of traffic situations and determines maneuvers to follow a global path as well as to avoid collisions. The trajectory generation generates a trajectory to achieve the given maneuver by the decision-making module. The system is implemented in an open-source robot operating system to provide a reusable, hardware-independent software platform; it is then tested on a closed road with other vehicles in several scenarios similar to real road environments to verify that it works properly for cooperative driving with a driver and automated driving.
Developing and Evaluating New ICT Innovation System: Case Study of Korea's Smart Media Industry
Kim, Eungdo ; Lee, Daeho ; Bae, Kheesu ; Rim, Myunghwan ;
ETRI Journal, volume 37, issue 5, 2015, Pages 1044~1054
DOI : 10.4218/etrij.15.0115.0059
The smart media (SM) industry has demonstrated that it has the characteristics to increase user innovative activities, enhance open innovativeness, and increase the segmentation of innovation value. This study introduces and evaluates an innovation system that reflects the characteristics of the SM industry. We categorize the SM industry into hardware, network, platform, and content industries and perform an AHP analysis (based on a survey of 96 experts) to evaluate the relative importance of the factors/factor groups affecting the creation of innovation. The results show that 'collaboration activity" is a more important factor than other innovation factor groups (financial support, R&D, policy environment, human resources) in the SM industry. The results also show that the important factors/factor groups differ by industry.