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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
The Journal of Korean Institute of Communications and Information Sciences
Journal Basic Information
Journal DOI :
The Korean Institute of Communications and Information Sciences
Editor in Chief :
Kyung-Hi Chang / Song Chong / Jong-Taek Oh / Jae-Jin Lee / Myung-Sik Yoo
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
Selecting the target year
Performance Analysis of Amplify-and-Forward Relaying in Cooperative Networks with Partial Relay Selection
Hwang, Ho-seon ; Ahn, Kyung-seung ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 12, 2015, Pages 2317~2323
DOI : 10.7840/kics.2015.40.12.2317
In this paper, we analyze the performance of dual-hop amplify-and-forward (AF) relaying in cooperative networks with partial relay selection. An AF relay gain considered in this paper includes channel-noise-assisted relay gain. Leveraging a received signal-to-noise ratio (SNR) model, we derive exact closed-form expressions for the probability density function (pdf) and cumulative distribution function (cdf) of the end-to-end SNR. Moreover, an exact closed-form expression of the ergodic capacity for dual-hop AF relaying with channel-noise-assisted relay gain and partial relay selection is investigated. The analytical results shown in this paper are confirmed by Monte-Carlo simulations.
Performance Analysis of Correntropy-Based Blind Algorithms Robust to Impulsive Noise
Kim, Namyong ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 12, 2015, Pages 2324~2330
DOI : 10.7840/kics.2015.40.12.2324
In blind signal processing in impulsive noise environment the maximum cross-correntropy (MCC) algorithm shows superior performance compared to MSE-based algorithms. But optimum weight conditions of MCC algorithm and its properties related with robustness to impulsive noise have not been studied sufficiently. In this paper, through the analysis of the behavior of its optimum weight and the relationship with the MSE-based LMS algorithm, it is shown that the optimum weight of MCC and MSE-based LMS have an equal solution. Also the factor that keeps optimum weight of MCC undisturbed and stable under impulsive noise is proven to be the magnitude controlled input through simulation.
Block Diagonal Decomposition Using Uniform Channel Decomposition for Multicell MIMO Broadcast Channels
Park, Yu-han ; Park, Daeyoung ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 12, 2015, Pages 2331~2342
DOI : 10.7840/kics.2015.40.12.2331
In this paper, we design non-linear transmitter and receiver using a uniform channel decomposition (UCD) to take account of inter-cell interference in multi-cell downlink systems. The designed UCD scheme brings forth the same SINR for all sub-channels in each cell. It provides great convenience to modulation/coding process and achieves the maximum diversity gain. The simulation results confirm that it exhibits a lower BER than the conventional method.
Motion Field Estimation Using U-disparity Map and Forward-Backward Error Removal in Vehicle Environment
Seo, Seungwoo ; Lee, Gyucheol ; Lee, Sangyong ; Yoo, Jisang ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 12, 2015, Pages 2343~2352
DOI : 10.7840/kics.2015.40.12.2343
In this paper, we propose novel motion field estimation method using U-disparity map and forward-backward error removal in vehicles environment. Generally, in an image obtained from a camera attached in a vehicle, a motion vector occurs according to the movement of the vehicle. but this motion vector is less accurate by effect of surrounding environment. In particular, it is difficult to extract an accurate motion vector because of adjacent pixels which are similar each other on the road surface. Therefore, proposed method removes road surface by using U-disparity map and performs optical flow about remaining portion. forward-backward error removal method is used to improve the accuracy of the motion vector. Finally, we predict motion of the vehicle by applying RANSAC(RANdom SAmple Consensus) from acquired motion vector and then generate motion field. Through experimental results, we show that the proposed algorithm performs better than old schemes.
Interference Cancellation for Wireless LAN Systems Using Full Duplex Communications
Han, Suyong ; Song, Choonggeun ; Choi, Jihoon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 12, 2015, Pages 2353~2362
DOI : 10.7840/kics.2015.40.12.2353
In this paper, we employ the single channel full duplex radio for wireless local area network (WLAN) systems, and design digital interference cancellers using adaptive signal processing. When the full duplex scheme is used for WLAN systems with multiple transmit and receive antennas, some interference is caused through the feedback of transmit signals from multiple antennas. To remove the feedback interference, we derive the least mean square (LMS), normalized LMS (NLMS), and recursive least squares (RLS) algorithms based on adaptive signal processing techniques. In addition, we analyze the theoretical convergence of the proposed LMS and RLS methods. The channel capacity of full duplex radios increases by two times than that of half duplex radios, when the packet error rate (PER) performances for the two systems are identical. Through numerical simulations in WLAN systems, it is shown that the full duplex method with the proposed interference cancellers has a similar PER performance with the conventional half duplex transmission scheme.
Feature Matching Algorithm Robust To Viewpoint Change
Jung, Hyun-jo ; Yoo, Ji-sang ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 12, 2015, Pages 2363~2371
DOI : 10.7840/kics.2015.40.12.2363
In this paper, we propose a new feature matching algorithm which is robust to the viewpoint change by using the FAST(Features from Accelerated Segment Test) feature detector and the SIFT(Scale Invariant Feature Transform) feature descriptor. The original FAST algorithm unnecessarily results in many feature points along the edges in the image. To solve this problem, we apply the principal curvatures for refining it. We use the SIFT descriptor to describe the extracted feature points and calculate the homography matrix through the RANSAC(RANdom SAmple Consensus) with the matching pairs obtained from the two different viewpoint images. To make feature matching robust to the viewpoint change, we classify the matching pairs by calculating the Euclidean distance between the transformed coordinates by the homography transformation with feature points in the reference image and the coordinates of the feature points in the different viewpoint image. Through the experimental results, it is shown that the proposed algorithm has better performance than the conventional feature matching algorithms even though it has much less computational load.
Frequency Allocation and Path Selection Scheme in Underlay Cognitive Radio Networks Using Network Coding
Lee, Do-Haeng ; Lee, Won Hyoung ; Kang, Sung-Min ; Hwang, Ho Young ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 12, 2015, Pages 2372~2380
DOI : 10.7840/kics.2015.40.12.2372
In this paper, we propose frequency allocation and path selection scheme in underlay cognitive radio (CR) networks using network coding. In the proposed scheme, we choose the path with consideration of network coding and interference temperature in underlay CR networks and propose an optimization problem to maximize the system throughput of secondary users (SUs). Then, we represent the proposed optimization problem as the multi-dimensional multiple-choice knapsack problem and give the theoretical upper bound for the system throughput of SUs by using linear programming. Finally, we compute the system throughput of SUs by using brute-force search (BFS) and link quality first (LQF) scheme in underlay CR networks. Simulation results show that the system throughput of SUs with BFS is higher than that with LQF in underlay CR networks with and without application of network coding, respectively.
Joint Operation of ABS with Power Control and Derivation of an Effective ABS Ratio for LTE Hetnet Environments
Sung, No-Hoon ; Choi, Young-June ; Jang, Ji-Woong ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 12, 2015, Pages 2381~2388
DOI : 10.7840/kics.2015.40.12.2381
It has been known that interference occurs between macrocell ans small-cell base stations in a heterogeneous network (HetNet) of LTE-A. For solving this problem, 3GPP suggested eICIC (Enhanced Inter Cell Interference Coordination) that includes ABS (Almost Blank Subframe) and power control. This paper proposes to use ABS with power control and derives an effective ABS ratio as a function of the number of users and HeNBs. Through simulation, we confirm that integration of ABS and power control can mitigate interference than using ABS only. Furthermore, we verify that an effective ABS ratio is different depending on the number of users and HeNBs.
Feasibility of Interference Alignment for Full-Duplex MIMO Cellular Networks
Kim, Kiyeon ; Yang, Janghoon ; Jeon, Sang-Woon ; Kim, Dong Ku ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 12, 2015, Pages 2389~2391
DOI : 10.7840/kics.2015.40.12.2389
The feasibility condition of interference alignment (IA) for full-duplex (FD) multiple-input multipleoutput (MIMO) cellular networks is considered. The necessary and sufficient condition on the IA feasibility is established, characterizing the achievable sum degrees of freedom (DoF). The results demonstrate that FD operation with appropriate IA is able to improve the sum DoF on the conventional half-duplex operation.
Adaptable PANID Generation Scheme for Resolving Address Conflict Based on Hash Mechanism in IoT Environment
Lee, Jaeho ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 12, 2015, Pages 2392~2400
DOI : 10.7840/kics.2015.40.12.2392
Zigbee, which was a representative standard technology for dealing low energy and mesh networks in large deployment area such as smart home, smart building, and massive sensor networks, has been developed and deployed for increasing communication area by using Ad hoc method. It has been originally developed based on IEEE 802.15.4 standard so every node needs 48bit unique address defined by IEEE. However, it is absolutely inefficient to assign an unique address to every communication node where it would be deployed through large-scale network area, e.g., smart lighting and massive sensor networks, because there could be variously multiple companies to deploy network infrastructure and they could have different policy to assign node ID. To prevent the problem, this paper proposes a method of dynamic PANID assignment in overall Personal Coordinators, and also proposes a method for addressing PANID conflict problem which could be derived from dynamic PANID assignment.
Improvement of Handoff Performance Using Prefetched AP Information in IEEE 802.11
Lee, Han-Na ; Kim, Hyang-Mi ; Kim, Sangkyung ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 12, 2015, Pages 2401~2409
DOI : 10.7840/kics.2015.40.12.2401
This paper proposes the improved handoff mechanism for IEEE 802.11 wireless LANs. When a wireless mobile node moves out of the coverage of its currently associated AP(Access Point) and needs to be re-associated with a new AP, a handoff procedure is initiated. Channel scanning process during a handoff procedure occupies over 90% of total handoff latency. Long latency leads to many packet losses and service discontinuity, which degrades wireless network performance. This paper describes about the new mechanism to improve handoff performance by skipping channel scanning during a handoff procedure. In oerder for that, acquires neighboring AP information such as its address, location, channel number in use, the number of associated nodes before handoff, and delivers the information to its associated mobile nodes. The mobile nodes can reduce handoff latency and perform more exact handoff using the delivered AP information. We have conducted simulations to analyze our proposal's performance and confirmed that handoff latency and the number of handoff occurrences are decreased.
Self-Organized Resource Allocation for Femtocell Network to Mitigate Downlink Interference
Sable, Smita ; Bae, Jinsoo ; Lee, Kyung-Geun ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 12, 2015, Pages 2410~2418
DOI : 10.7840/kics.2015.40.12.2410
In this paper, we consider the femto users and their mutual interference as graph elements, nodes and weighted edges, respectively. The total bandwidth is divided into a number of resource blocks (RBs) and these are assigned to the femto user equipment (FUEs) using a graph coloring algorithm. In addition, resources blocks are assigned to the femto users to avoid inter-cell interference. The proposed scheme is compared with the traditional scheduling schemes in terms of throughput and fairness and performance improvement is achieved by exploiting the graph coloring scheme.
A Named Data Networking Testbed with Global NDN Connection
Ni, Alexander ; Lim, Huhnkuk ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 12, 2015, Pages 2419~2426
DOI : 10.7840/kics.2015.40.12.2419
Named Data Networking (NDN) is one of the powerfully evolving future internet architectures. In this paper installation, configuration and several tests are addressed to show how well and properly our NDN testbed have been prepared and established using NDN platform, in order to have interoperability with global NDN testbed. Global NDN testbed status with our NDN node participation was addressed. To verify one reachability on the NDN connection to global NDN testbed, a latency result is presented using NDN ping test.
Gain Enhancement of a Circularly-Polarized Patch Antenna with a Double-Layered Superstrate for Wireless LAN
Lee, Sangrok ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 12, 2015, Pages 2427~2433
DOI : 10.7840/kics.2015.40.12.2427
A high-gain circularly-polarized patch antenna with a double-layered superstrate is proposed operating at a wireless LAN frequency. A superstrate has an array of metallic periodic unit cells and is located above the patch antenna with an air-gap. The designed antenna has a high gain of over 9.59dBi, which is the gain enhancement of 6.48dB compared to the patch antenna without superstrate. And it has a low axial ratio of under 3dB, so that it maintains the circular polarization of the patch antenna. The optimum air-gap height at the superstrate of
arrays is 25mm, which is equivalent to about
at the frequency of 2.45GHz. We confirmed that the double-layered stacking of a superstrate increases the effective aperture size and hence it leads to enhance a gain of the patch antenna.
International Benchmarking on Factors Affecting the Number of Country Domain Name
Kim, So-ra ; Jun, Hyo-Jung ; Kim, Tae-Sung ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 12, 2015, Pages 2434~2442
DOI : 10.7840/kics.2015.40.12.2434
With the arrival of the era of the Internet of Things (IoT), identification of an individual object is gaining significance. Internet address resources such as domain name, IP address, and OID are expected to play the role of an identifier and demand for them is also expected to increase. Accordingly, it becomes important to obtain the Internet address resources. As the Internet address resources market development, Internet address resources at the present time there is a need to gauge whether the potential to develop into industry. For this purpose, we have selected factors affecting the number of country domain name with 18 countries among OECD member countries as research target and carried out a regression analysis.
Load-Aware Cell Selection Method for Efficient Use of Network Resources
Park, Jaesung ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 12, 2015, Pages 2443~2449
DOI : 10.7840/kics.2015.40.12.2443
Downlink (DL) data rate for a MS is influenced by not only the signal to interference and noise ratio (SINR) but also the amount of radio resources allocated to the MS. Therefore, when a MS uses SINR to select a cell to associate with, it cannot receive the fastest DL data rate all the time if it associates with a congested cell. Moreover, the SINR-based cell selection may result in cell loads unbalance, which decreases the efficiency of a network. To address the issue, we propose a novel cell selection method by considering not only SINR but also a cell load which are combined into two cell selection criteria. One is the maximum achievable data rate and the other is the minimum outage probability. The simulation results show that the cell selection based on the maximum achievable data rate is superior to the SINR-based method and the method using the minimum outage probability in terms of the system efficiency and the fairness in cell loads while the cell selection method based on the minimum outage probability is superior to the others in terms of the outage probability of a MS.
Two Solutions for Unnecessary Path Update Problem in Multi-Sink Based IoT Networks
Lee, Sungwon ; Kang, Hyunwoo ; Yoo, Hongsoek ; Jeong, Yonghwan ; Kim, Dongkyun ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 12, 2015, Pages 2450~2460
DOI : 10.7840/kics.2015.40.12.2450
Recently, as interest in IoT (Internet of Things) increase, research and standardization of a new protocol which reflects the characteristics of IoT has progressed. Among them, RPL(IPv6 for Low-Power Lossy Network) is a standardized routing protocol for IoT. RPL utilizes DIO (DODAG Information Object) messages which is flooded from the sink node to the whole network for path establish and maintenance. However, in large scale networks, not only a long time is required to propagate the DIO message to the whole networks but also a bottleneck effect around the sink node is occurred. Multi-sink based approaches which take advantage of reducing routing overhead and bottleneck effect are widely used to solve these problems. In this paper, we define 'unnecessary path update problems' that may arise when applying the RPL protocol to the multi sink based IoT networks and propose two methods namely Routing Metric based Path Update Decision method and Immediate Successor based Path Update Decision method for selective routing update.
Study on the Linear Non-Complementary 2-Arm Slot Sinuous Antenna for Low Input Impedance
Yoon, Sung Hyun ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 12, 2015, Pages 2461~2468
DOI : 10.7840/kics.2015.40.12.2461
Sinuous antenna is utilized in a number of application like direction-finding system that require ultra wideband, but because of high input impedance of the antenna, it is difficult to design low-profile antenna and balun. In this study, we used Babinet's principle and proposed linear 2-arm slot sinuous antenna that is divided sinuous 6 cell with equal spacing between the most largest radius
and the smallest radius
instead of exponential 2-arm strip sinuous antenna for 2-18[GHz] frequency band to obtain low input impedance, and we have studied -10dB bandwidth of antenna when has been fed by
at feeder point. As a result, we have obtained return loss below than -10dB for about 4-18[GHz] frequency range in the case of slot antenna, but at all frequency band, return loss was above -10dB in the case of strip antenna.
Hardware-Based High Performance XML Parsing Technique Using an FPGA
Lee, Kyu-hee ; Seo, Byeong-seok ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 12, 2015, Pages 2469~2475
DOI : 10.7840/kics.2015.40.12.2469
A structured XML has been widely used to present services on various Web-services. The XML is also used for digital documents and digital signatures and for the representation of multimedia files in email systems. The XML document should be firstly parsed to access elements in the XML. The parsing is the most compute-instensive task in the use of XML documents. Most of the previous work has focused on hardware based XML parsers in order to improve parsing performance, while a little work has studied parsing techniques. We present the high performance parsing technique which can be used all of XML parsers and design hardware based XML parser using an FPGA. The proposed parsing technique uses element analyzers instead of the state machine and performs multibyte-based element matching. As a result, our parsing technique can reduce the number of clock cycles per byte(CPB) and does not need to require any preprocessing, such as loading XML data into memory. Compared to other parsers, our parser acheives 1.33~1.82 times improvement in the system performance. Therefore, the proposed parsing technique can process XML documents in real time and is suitable for applying to all of XML parsers.
Study on Hidden Period Estimation in Propeller Noise by Applying Compressed Sensing to Auto-Correlation and Filter-Bank Structure
Lim, Jun-Seok ; Pyeon, Yong-Guk ; Hong, Woo-Young ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 12, 2015, Pages 2476~2484
DOI : 10.7840/kics.2015.40.12.2476
Narrow band signal estimation and broad band signal estimation can be used to detect the ship-radiated noise. The broad band signal estimation method to detect the ship-radiated noise is called DEMON (Detection of Envelop Modulation On Noise). This paper proposes a new DEMON algorithm applying compressed sensing algorithm to filter bank and autocorrelation. We show the proposed algorithm estimates the hidden period in the wide band signal better than the conventional DEMON algorithm and the recently proposed filter-bank based DEMON algorithm. Especially we show that the proposed algorithm needs shorter data length than the conventional DEMON algorithm.
Tag Search System Using the Keyword Extraction and Similarity Evaluation
Jung, Jaein ; Yoo, Myungsik ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 12, 2015, Pages 2485~2487
DOI : 10.7840/kics.2015.40.12.2485
Recently, Hashtag is widely used in SNS like Facebook, Twitter and personal blogs. However, the efficiency of tag search system is poor due to the indiscriminate use of hashtags. To enhance the accuracy of tag search system, we proposed a tag search system using the keyword extraction and similarity evaluation. The experimental results show that the proposed system provides the higher accuracy on tag search results.
Facebook Fan Page Evaluation System Based on User Opinion Mining
Phan, Trong-Ngoc ; Yoo, Myungsik ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 12, 2015, Pages 2488~2490
DOI : 10.7840/kics.2015.40.12.2488
In this paper, we propose the Facebook fan page evaluation system, which evaluates user opinions based on lexicon-based analysis and positive/negative response from users. By comparing the performance with existing evaluation systems, it is verified that the proposed system can evaluate the fan page in more accurate way.
Technology and Issue on Embodiment of Smart Factory in Small-Medium Manufacturing Business
Park, Jong-man ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 12, 2015, Pages 2491~2502
DOI : 10.7840/kics.2015.40.12.2491
Main issue for embodiment of smart factory in small-medium manufacturing business(SMMB) is to whether might be successful or not in achieving a goal, exact materializing for smart factory related technology, and in seeking possible solutions for limited capacity to invest and develop technology. It is required for effective driving of manufacturing innovation 3.0 paradigm that ensures expertise to push forward technology policy based on value chain level of SMMB, and ensures detailed action plans by investment priority and development of core technology against global trend. This paper focuses to suggest countermeasure strategy and task through analysis of advanced technology and patent trend about industrial IoT(IIoT) and cyber physical system(CPS), and support embodiment of smart factory in underlying manufacturing innovation 3.0 scheme.
Implementation of Single-Phase Energy Measurement IC
Lee, Youn-Sung ; Seo, Hae-Moon ; Kim, Dong Ku ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 12, 2015, Pages 2503~2510
DOI : 10.7840/kics.2015.40.12.2503
This paper presents a single-phase energy measurement IC to measure electric power quantities. The entire IC includes two programmable gain amplifiers (PGAs), two
modulators, a reference circuit, a low-dropout (LDO) regulator, a temperature sensor, a filter unit, a computation engine, a calibration control unit, registers, and an external interface block. The proposed energy measurement IC is fabricated with
CMOS technology and housed in a 32-pin quad-flat no-leads (QFN) package. It operates at a clock speed of 4,096 kHz and consumes 10 mW in 3.3 V supply.
Active IP-RFID System for Maritime Logistics
Kim, Tae-Hoon ; Lee, Byung-Ha ; Park, Byung-Kwon ; Choi, Sung-Pil ; Moon, Young-Sik ; Jung, Jun-Woo ; Kim, Jae-Joong ; Choi, Hyong-Rim ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 12, 2015, Pages 2511~2519
DOI : 10.7840/kics.2015.40.12.2511
In maritime logistics, the technology for transmitting status information has been greatly developed, but it has not been available in general logistics environment or it is impossible to support two-way communication as it simply receives and transfers a container's information. In particular, to support two-way communication in all sections of the global maritime logistics, the address value, which can identify the tag, should be managed. In this context, to improve the 433 MHz-based RFID, the project called "DASH 7" has been conducted in recent years. However, it has stopped proceeding because of its slow progress, including the standardization and development of references. In this paper, we introduced an active IP-RFID system configuration for real-time communication in global maritime logistics using a two-way communication-which is characteristic of an IP-applying virtual address values in the RFID tag, and proposing its process and function. When you apply the IP-RFID system proposed in this paper, not only real-time status tracking in the maritime logistics area is possible, but it is also applicable for controlling the tag.
Alternative Scheme of INS-Dependent Positioning for Relative Navigation without GRUs
Kim, Ki-hyoung ; Lee, Kyu-man ; Lim, Jae-sung ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 12, 2015, Pages 2520~2527
DOI : 10.7840/kics.2015.40.12.2520
Position information is important to carry out military operations. In general, GPS is used to estimate position. However, GPS is vulnerable to jamming due to the low received signal strength, therefore GPS can be easily jammed. The relative navigation is an auxiliary navigation system defined in JTIDS. When GPS is jammed, the relative navigation requires ground reference units on the ground to operate accurately. If the ground reference unit does not exist, nodes operated by the relative navigation depend on the inertial navigation system to identify their position. However, this positioning scheme based on only INS causes accumulative position error, therefore the nodes cannot identify their position accurately for a long time. In this paper, we propose an alternative to reduce position error generated by depending inertial navigation system. In order to verify that the performance of proposed scheme is better than that of the existing scheme, various simulations are conducted.
Region-Based Error Concealment of Depth Map in Multiview Video
Kim, Wooyeun ; Shin, Jitae ; Oh, Byung Tae ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 12, 2015, Pages 2530~2538
DOI : 10.7840/kics.2015.40.12.2530
The pixel value of depth image is depth value so that different objects which are placed on nearby position have similar pixel value. Moreover, the pixels of depth image have distinct pixel values compared to adjacent pixels while those of color image has very similar values. Accordingly distorted depth image of multiview video plus depth (MVD) needs proper error concealment methods considering the characteristics of depth image when transmission errors are happened. In this paper, classifying regions of depth image to consider edge directions and then applying adaptive error concealment methods to each region are proposed. Recovered depth images utilize with multiview video data to synthesize intermediate-view point video. The synthesized view is evaluated by objective quality metrics to demonstrate proposed method performance.
Dynamic Frequency Reuse Scheme Based on Traffic Load Ratio for Heterogeneous Cellular Networks
Chung, Sungmoon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 12, 2015, Pages 2539~2548
DOI : 10.7840/kics.2015.40.12.2539
Overcoming inter-cell interference and spectrum scarcity are major issues in heterogeneous cellular networks. Static Frequency reuse schemes have been proposed as an effective way to manage the spectrum and reduce ICI(Inter cell Interference) in cellular networks. In a kind of static frequency reuse scheme, the allocations of transmission power and subcarriers in each cell are fixed prior to system deployment. This limits the potential performance of the static frequency reuse scheme. Also, most of dynamic frequency reuse schemes did not consider small cell and the network environment when the traffic load of each cell is heavy and non-uniform. In this paper, we propose an inter-cell resource allocation algorithm that dynamically optimizes subcarrier allocations for the multi-cell heterogeneous networks. The proposed dynamic frequency reuse scheme first finds the subcarrier usage in each cell-edge by using the exhaustive search and allocates subcarrier for all the cells except small cells. After that it allocates subcarrier for the small cell and then iteratively repeats the process. Proposed dynamic frequency reuse scheme performs better than previous frequency reuse schemes in terms of the throughput by improving the spectral efficiency due to it is able to adapt the network environment immediately when the traffic load of each cell is heavy and non-uniform.
On Non-Orthogonal Multiple Access (NOMA) in 5G Systems
Islam, SM Riazul ; Kim, Jae Moung ; Kwak, Kyung Sup ;
The Journal of Korean Institute of Communications and Information Sciences, volume 40, issue 12, 2015, Pages 2549~2558
DOI : 10.7840/kics.2015.40.12.2549
The non-orthogonal multiple access (NOMA) is one of the fledging paradigms which next generation radio access technologies are sprouting toward. The NOMA with superposition coding (SC) in the transmitter and successive interference cancellation (SIC) at the receiver comes with many desirable features and benefits over orthogonal multiple access (OMA) such as orthogonal frequency division multiple access (OFDMA) adopted by Long-Term Evolution (LTE). In this paper, we study the recent research trends on NOMA in 5G systems. We discuss the basic concept of NOMA and explain its aspects of importance for future radio access. Then, we provide a survey of the state of the art in NOMA for 5G systems in a categorized manner. Further, we analyze the NOMA performances with numerical examples; and provide some avenues for future research on NOMA on a set of open issues and challenges.