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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Journal of Korean Institute of Communications and Information Sciences
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The Korean Institute of Communications and Information Sciences
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Volume & Issues
Volume 40, Issue 12 - Dec 2015
Volume 40, Issue 11 - Nov 2015
Volume 40, Issue 10 - Oct 2015
Volume 40, Issue 9 - Sep 2015
Volume 40, Issue 8 - Aug 2015
Volume 40, Issue 7 - Jul 2015
Volume 40, Issue 6 - Jun 2015
Volume 40, Issue 5 - May 2015
Volume 40, Issue 4 - Apr 2015
Volume 40, Issue 3 - Mar 2015
Volume 40, Issue 2 - Feb 2015
Volume 40, Issue 1 - Jan 2015
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A New Decision-Directed Equalization with Improved Blind Convergence Properties by Error Scaling
Oh, Kil Nam ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 3, 2015, Pages 419~424
DOI : 10.7840/kics.2015.40.3.419
The Decision-directed (DD) algorithm is known to be not effective to initialize a blind equalizer in the channel conditions when the eye diagram of received signals is completely closed because it can not open the eye diagram enough. In this paper, we propose a new error to replace the error of the conventional DD algorithm. The new DD error is the conventional DD error scaled by the modulus of symbol decision, new DD algorithm using this error is effective to open the closed eye diagram in early stage of equalization unlike the conventional DD. The new DD algorithm appling the new error is showed excellent convergence characteristics as compared to the CMA widely used in blind initialization, particularly, is useful for equalization of signals having multimodulus. The performance of the new DD algorithm is verified through the simulation for the higher-order QAM signals.
OFDM Transmission Method Based on the Beam-Space MIMO System
Choi, Jinkyu ; An, Changyoung ; Ryu, Heung-Gyoon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 3, 2015, Pages 425~431
DOI : 10.7840/kics.2015.40.3.425
Beamspace Multiple-Input Multiple Output(MIMO) system can transmit multiple data by using Electronically Steerable Parasitic Array Radiator(ESPAR) antenna which has single Radio Frequency(RF)-chain. Beamspace MIMO system can reduce complexity of the system and size of antenna in comparison with the conventional MIMO system because of characteristic of ESPAR antenna using the single antenna and the RF-chain. Heretofore, only the research of transmitting single-carrier has been conducted by the use of beamspace MIMO system. Therefore, in this paper, we propose beamspace MIMO system based on Orthogonal Frequency Division Multiplexing(OFDM) for transmitting the multi-carrier and analysis the performance of this system. We find a proper reactance value which has good performance because proposed system changes the performance by the reactance values of parasitic elements. and we confirm that performance of the proposed system is similar to conventional MIMO system based on OFDM.
Spatial and Frequency Diversity Combining Order in Uplink SC-FDMA with SIMO Systems
Lee, Jin-Hui ; Choi, Kwonhue ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 3, 2015, Pages 432~440
DOI : 10.7840/kics.2015.40.3.432
We investigate BER performance according to the order of spatial and frequency diversity combining in uplink SC-FDMA of SIMO systems. It is found that frequency diversity combining (FDC) after spatial diversity combining (SDC) is better than the reverse order combing in all SNR (Signal to Noise Ratio) range. Also, it is shown that FDC after SDC requires less computational complexity than the reverse order combining.
Multicast Scheduling Scheme in Dense WLAN Systems
Kim, Namyeong ; Kim, Wonjung ; Pack, Sangheon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 3, 2015, Pages 441~450
DOI : 10.7840/kics.2015.40.3.441
Nowadays, many WLAN access points (APs) are deployed in hotspot areas such as shopping malls and stations. As the number of WLAN APs deployed increases, how to manage densely deployed APs in an efficient manner becomes one of the most important issues in WLANs. In this environment, uncoordinated multicast services can lead to frequent collisions due to simultaneous transmissions among APs. In this paper, we propose a multicast scheduling algorithm that can exploit simultaneous transmissions in multiple sectors and avoid redundant transmissions in dense networks. Simulation results demonstrate that the proposed scheme can reduce the multicast transmission latency compared to comparison scheduling schemes.
OFDMA FD-MAC Protocol Based on the Channel Information
Cheon, Hye-Rim ; Kim, Jae-Hyun ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 3, 2015, Pages 451~458
DOI : 10.7840/kics.2015.40.3.451
The deployment density of AP increases as well as the density WLAN stations due to increase of WLAN use and the real performance of WLAN is degraded. To improve the performance, there are many PHY/MAC technologies and OFDMA and full duplex are promising technologies among them. In conventional OFDMA WLAN MAC relate works, there are some limitations in terms of channel utilization and collision probability. Thus, it need to research for effective channel allocation protocol. Full duplex can transmit data on the same time and same frequency resource so it can allocate channel more flexible than half duplex. In this paper, we prose the OFDMA FD-MAC(Full Duplex MAC) protocol that it allocates the sub-channels based on the idle channel information for full duplex pair. In addition, it shows the throughput improvement by performance analysis.
Channel Estimation and Analog Beam Selection for Uplink Multiuser Hybrid Beamforming System
Kim, Myeong-Jin ; Ko, Young-Chai ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 3, 2015, Pages 459~468
DOI : 10.7840/kics.2015.40.3.459
In this paper, we consider an uplink multiuser hybrid beamforming system where an access point (AP) communicates with multiple users simultaneously. The performance of the uplink multiuser hybrid beamforming system depends on the effective channel which is given by the product of the channel matrix and the analog beams. Therefore, to maximize the performance, we need to obtain the channel information and then select the analog beams appropriately by using the acquired channel information. In this paper, we propose the channel estimation method and low complexity analog beam selection algorithm for the uplink multiuser hybrid beamforming system. Additionally, our analysis shows that the proposed low complexity analog beam selection algorithm provides much less complexity than the optimum analog beam selection algorithm. From the numerical results, we confirm that the proposed low complexity analog beam selection algorithm has little performance degradation in spite of much less complexity than the optimum analog beam selection algorithm under the equal system configuration.
Joint Spatial Division and Reuse for Maximizing Network Throughput in Densely-Deployed Massive MIMO WLANs
Choi, Kyung Jun ; Kim, Kyung Jun ; Kim, Kwang Soon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 3, 2015, Pages 469~477
DOI : 10.7840/kics.2015.40.3.469
In this paper, joint spatial division and reuse (JSDR) scheme is proposed for maximizing network throughput in densely-deployed wireless local area networks equipped with massive antenna array. The proposed JSDR scheme divides the massive spatial space into two subspaces: one is for suppressing the interference from the neighboring access points and another is for sensing the carrier sensing and transmitting the information-bearing signals to intended stations. By using computer simulation, the proposed JSDR can provide 133% higher network throughput, compared to the carrier sensing technique defined in the IEEE 802.11 standard so that the proposed JSDR is suitable for the next generation WLAN systems.
Yellow-Light TCP: Energy-Saving Protocol for Mobile Data Transmission
Choi, Won-Jun ; Ramneek, Ramneek ; Seok, Woo-Jin ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 3, 2015, Pages 478~490
DOI : 10.7840/kics.2015.40.3.478
Abundant data has been generated over the internet as the arrival of information age. To share the information, Wired, wireless network are required to transmit the data. Especially, In the wireless network which is using mobile device based on battery, energy consumption is growing due to uploading, downloading the abundant data on mobile device. In order to solve the problem, This paper addresses the protocol of the modified TCP congestion control that is being used for the most network protocol to save energy.
Construction of [2
-1+k, k, 2
+1] Codes Attaining Griesmer Bound and Its Locality
Kim, Jung-Hyun ; Nam, Mi-Young ; Park, Ki-Hyeon ; Song, Hong-Yeop ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 3, 2015, Pages 491~496
DOI : 10.7840/kics.2015.40.3.491
In this paper, we introduce two classes of optimal codes, [
] simplex codes and [
] codes, attaining Griesmer bound with equality. We further present and compare the locality of them. The [
] codes have good locality property as well as optimal code length with given code dimension and minimum distance. Therefore, we expect that [
] codes can be applied to various distributed storage systems.
PS-Net : Personalized Secure Wi-Fi Networks
Lee, Nam-Seh ; Lee, Ju-Ho ; Jeong, Choong-Kyo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 3, 2015, Pages 497~505
DOI : 10.7840/kics.2015.40.3.497
Existing Wi-Fi networks require users to follow network settings of the AP (Access Point), resulting in inconveniences for users, and the password of the AP is shared by all users connected to the AP, causing security information leaks as time goes by. We propose, in this work, a personalized secure Wi-Fi network, in which each user is assigned her own virtual Wi-Fi network. One virtual Wi-Fi per user makes the user-centric network configuration possible. A user sets a pair of her own SSID and password on her device a priori, and the AP publishes its public key in a suitable way. The AP also maintains an open Wi-Fi channel, to which users can connect anytime. On user's request, the user device sends a connection request message containing a pair of SSID and password encrypted with the AP's public key. Receiving the connection request message, the AP instantiates a new virtual AP secured with the pair of SSID and password, which is dedicated to that single user device. This virtual network is securer because the password is not shared among users. It is more convenient because the network adapts itself to the user device. Experiments show that these advantages are obtained with negligible degradation in the throughput performance.
Group Synchronization Method Using Adaptive Synchronization Delay Time for Media Streaming
Kwon, Dongwoo ; Ok, Kisu ; Kim, Hyeonwoo ; Ju, Hongtaek ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 3, 2015, Pages 506~515
DOI : 10.7840/kics.2015.40.3.506
In this paper, we propose a group playback synchronization method using adaptive synchronization delay time by the bit rate of media to synchronize a play position of streaming media between mobile smart devices. This method consists of streaming server-side and client-side synchronization algorithms based on synchronization delay time which includes connection time, control packet transmission time, streaming data buffering time, and synchronization processing time. We implement the Android media player application with synchronization support using the proposed algorithms and present the result of performance evaluation.
Autonomous Ad hoc Network Construction Method for Scalable Media Streaming Between Mobile Smart Devices
Kwon, Dongwoo ; Je, Huigwang ; Kim, Hyeonwoo ; Ju, Hongtaek ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 3, 2015, Pages 516~528
DOI : 10.7840/kics.2015.40.3.516
In this paper, we propose mobile ad hoc network configuration and its autonomous network construction method for efficiency and scalability of media streaming for mobile smart devices. To provide scalable network configuration for streaming traffic distribution, an IEEE 802.11 infrastructure network and ad hoc networks are hierarchically built. The proposed method autonomously configures a hierarchical streaming network by competition based on performance and states of devices and the wireless network, not depending on any specific nodes. Finally, we conduct performance measurement for the proposed configuration and analyze the experimental result.
The User Terminal Registration Method in Proximity Using the Virtual ISIM for Providing Service Continuity
Yim, Jong-Choul ; Kim, Sang-Ha ; Keum, Chang-Sup ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 3, 2015, Pages 529~540
DOI : 10.7840/kics.2015.40.3.529
The NGN should support an ubiquitous environment in which users can use multiple devices. Especially, services should be provided to users in a seamless manner across multiple devices which are dynamically found in users' vicinity. Therefore, supporting service continuity is essential in the NGN. Currently the IMS, which is a session control layer for the NGN, deals with session control procedures in detail for service continuity. However, the IMS provides limited methods how users can find target terminals for transferring the session. The target terminals tend to be located near in user's physical location, and could be shared among different users. For providing better service experience in the NGN, The NGN needs to encompass methods to enable for users to use the dynamically-found terminals in users' vicinity seamlessly. In this paper, we introduce a novel registration method based on virtual ISIM by which the target terminals in user's vicinity can register themselves to the IMS, and also we discuss how service continuity is supported.
Big-Data Traffic Analysis for the Campus Network Resource Efficiency
An, Hyun-Min ; Lee, Su-Kang ; Sim, Kyu-Seok ; Kim, Ik-Han ; Jin, Seo-Hoon ; Kim, Myung-Sup ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 3, 2015, Pages 541~550
DOI : 10.7840/kics.2015.40.3.541
The importance of efficient enterprise network management has been emphasized continuously because of the rapid utilization of Internet in a limited resource environment. For the efficient network management, the management policy that reflects the characteristics of a specific network extracted from long-term traffic analysis is essential. However, the long-term traffic data could not be handled in the past and there was only simple analysis with the shot-term traffic data. However, as the big data analytics platforms are developed, the long-term traffic data can be analyzed easily. Recently, enterprise network resource efficiency through the long-term traffic analysis is required. In this paper, we propose the methods of collecting, storing and managing the long-term enterprise traffic data. We define several classification categories, and propose a novel network resource efficiency through the multidirectional statistical analysis of classified long-term traffic. The proposed method adopted to the campus network for the evaluation. The analysis results shows that, for the efficient enterprise network management, the QoS policy must be adopted in different rules that is tuned by time, space, and the purpose.
Analysis of Time-Based Unauthorized AP Detection Methods According to Hardware Performance of Unauthorized AP
Jang, Rhong-Ho ; Kang, Jeon-Il ; Nyang, Dae-Hun ; Lee, Kyung-Hee ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 3, 2015, Pages 551~558
DOI : 10.7840/kics.2015.40.3.551
As more people use Wi-Fi and hotspot, unauthorized APs become one of big security problems in modern society. From the beginning of 2010, researchers study about unauthorized AP continually and contributed a lot of methods of detecting unauthorized AP that use wireless resources. Many researches about unauthorized AP detection use time-delay measurement (e.g., average or standard deviation) which is caused by additional wireless connection. In the most previous researches, however, the unauthorized APs consist of laptop and pulg-in Wi-Fi adaptor, and researchers did not concern about time-delay caused by software network sharing. In this paper, we show that existing unauthorized AP detection scheme that can not efficiently classify the high performance unauthorized AP.
Performance Analysis of a Cellular Networks Using Power Control Based Frequency Reuse Partitioning
Mohsini, Mustafa Habibu ; Kim, Seung-Yeon ; Cho, Choong-Ho ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 3, 2015, Pages 559~567
DOI : 10.7840/kics.2015.40.3.559
This paper focuses on evaluating the performance of a cellular network using power control based frequency reuse partitioning (FRP) in downlink (DL). In our work, in order to have the realistic environment, the spectral efficiency of the system is evaluated through traffic analysis, which most of the previous works did not consider. To further decrease the cell edge user's outage, the concept of power ratio is introduced and applied to the DL FRP based cellular network. In considering network topology, we first divide the cell coverage area into two regions, the inner and outer regions. We then allocate different sub-bands in the inner and outer regions of each cell. In the analysis, for each zone ratio, the performance of FRP system is evaluated for the given number of power ratios. We consider performance metrics such as call blocking probability, channel utilization, outage probability and effective throughput. The simulation results show that there is a significant improvement in the outage experienced by outer UEs with power control scheme compared to that with no power control scheme and an increase in overall system throughput.
RFID Tag Ownership Relocation Protocol Based on Trusted Third Party
Kim, Young-Sik ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 3, 2015, Pages 568~574
DOI : 10.7840/kics.2015.40.3.568
Recently RFID not only is widely utilized in various fields such as inventory management, merchandize logistics, etc., but also, has evolved as an important component of the Internet of Things (IoT). According to increasing the utilization field of RIFD, studies for security and privacy for RFID system have been made diverse. Among them, the ownership transfer protocols for RFID tags have also been proposed in connection with the purchase of products embedded with RFID tag. Recently, Kapoor and Piramuthu proposed a RFID ownership transfer protocol to solve the problems of security weakness of the previous RFID ownership transfer protocols. In this paper, we show that Kapoor-Piramuthu's protocol also has security problems and provide a new protocol to resolve them. Security analysis of newly proposed protocol shows the security concerns are resolved.
Application Traffic Identification Speed Improvement by Optimizing Payload Signature Matching Sequence
Lee, Sung-Ho ; Park, Jun-Sang ; Kim, Myung-Sup ; Seok, Woojin ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 3, 2015, Pages 575~585
DOI : 10.7840/kics.2015.40.3.575
The traffic classification is a preliminary and essential step for stable network service provision and efficient network resource management. However, the payload signature-based method has significant drawbacks in high-speed network environment that the processing speed is much slower than other methods such as header-based and statistical methods. In addition, as signature numbers are increasing, traffic analysis speed also declines because of signature matching method that does not consider analytic efficiency of each signature and traffic occurrence feature. In this paper, we propose a signature list reordering method in order by analytic value of each signature. When we reordered the signature list by the proposed method, we achieved about 30% improvement in speed of the traffic analysis compared with random signature list.
VLC Based Positioning Scheme in Vehicle-to-Infra(V2I) Environment
Kim, Byung Wook ; Song, Deok-Weon ; Lee, Ji-Hwan ; Jung, Sung-Yoon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 3, 2015, Pages 588~594
DOI : 10.7840/kics.2015.40.3.588
Although GPS technology for location positioning system has been widely used, it is difficult to be used in intelligent transport systems, due to the large positioning error and limited area for receiving radio signals. Thanks to the rapid development of LED technology, LED lights become popular in many applications. Especially, visible light communications (VLC) has raised a lot of interests because of the simultaneous functioning of LED illumination and communication. Recent studies on positioning system using VLC mainly focused on indoor environments and still difficult to satisfy positioning accuracy and simple implementation simultaneously. In this paper, we propose a positioning system based on VLC using the coordinate information of LEDs installed on the road infrastructure. Extracting the LED signal, obtained through VLC, from the easily accessible camera image, it is possible to estimate the position of the car on the road. Simulation results show that the proposed scheme can achieve a high positioning accuracy of 1 m when large number of pixels is utilized and the distance from the LED light is close.
Performance of CSK Scheme for V2I Visible Light Communication
Kim, Hyeon-Cheol ; Kim, Byung Wook ; Jung, Sung-Yoon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 3, 2015, Pages 595~601
DOI : 10.7840/kics.2015.40.3.595
These days, research related to Intelligent Transportation System (ITS) technology is being widely considered. ITS is inevitable for future transportation systems to reduce accidents, congestion, and offer a smooth flow of traffic. The use of Visible Light Communication (VLC) in ITS systems has been considered widely because of its EMC/EMI free and LED infrastructure reusable properties. Among the VLC schemes, this study analyzed the performance of the Color Shift Keying (CSK) scheme under a Vehicle-to-Infrastructure (V2I) downlink scenario to verify the capability of CSK as a communication tool for ITS. By modeling daylight noise using the modified Blackbody radiation model, this study examined the performance of V2I VLC under daytime conditions. The relationship between BER, the communication distance, and the amount of ambient-light noises under the pre-described V2I scenario were determined by simulations.
Data Dissemination in LTE-D2D Based Vehicular Network
Shim, Yong-Hui ; Kim, Young-Han ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 3, 2015, Pages 602~612
DOI : 10.7840/kics.2015.40.3.602
Current IEEE 802.11p which is suggested for vehicle to vehicle communication supports one hop communication. Thus, it has a limitation to carry out efficient data dissemination. In this thesis, we suggest LTE-D2D based vehicle network to provide efficient data dissemination in the vehicle environment. In this network architecture, we use name based message with IP packet options and we put the intermediate vehicle node called 'super vehicle node' and each normal vehicle node in the cell requests data to the super vehicle node. The super vehicle node responses data to the normal vehicle node. Performance analysis is based mathematical modeling. We compare LTE cellular network to LTE-D2D based vehicle network about throughput according to packet delivery time.