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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 35, Issue 12C - Dec 2010
Volume 35, Issue 12B - Dec 2010
Volume 35, Issue 12A - Dec 2010
Volume 35, Issue 11C - Nov 2010
Volume 35, Issue 11B - Nov 2010
Volume 35, Issue 11A - Nov 2010
Volume 35, Issue 10C - Oct 2010
Volume 35, Issue 10B - Oct 2010
Volume 35, Issue 10A - Oct 2010
Volume 35, Issue 9C - Sep 2010
Volume 35, Issue 9B - Sep 2010
Volume 35, Issue 9A - Sep 2010
Volume 35, Issue 8C - Aug 2010
Volume 35, Issue 8B - Aug 2010
Volume 35, Issue 8A - Aug 2010
Volume 35, Issue 7C - Jul 2010
Volume 35, Issue 7B - Jul 2010
Volume 35, Issue 7A - Jul 2010
Volume 35, Issue 6C - Jun 2010
Volume 35, Issue 6B - Jun 2010
Volume 35, Issue 6A - Jun 2010
Volume 35, Issue 5C - May 2010
Volume 35, Issue 5B - May 2010
Volume 35, Issue 5A - May 2010
Volume 35, Issue 4C - Apr 2010
Volume 35, Issue 4B - Apr 2010
Volume 35, Issue 4A - Apr 2010
Volume 35, Issue 3C - Mar 2010
Volume 35, Issue 3B - Mar 2010
Volume 35, Issue 3A - Mar 2010
Volume 35, Issue 2C - Feb 2010
Volume 35, Issue 2B - Feb 2010
Volume 35, Issue 2A - Feb 2010
Volume 35, Issue 1C - Jan 2010
Volume 35, Issue 1B - Jan 2010
Volume 35, Issue 1A - Jan 2010
Selecting the target year
A Design of SINR Measurement Unit for IEEE 802.16m
Kim, Jun-Woo ; Park, Youn-Ok ; Kim, Whan-Woo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 12A, 2010, Pages 1097~1104
This paper presents the signal-to-noise ratio (SNR) and signal-to-interference plus noise ratio (SINR) estimation based on A-Preamble of IEEE 802.16m IMT-Advanced WiMax system with simulation results. The downlink signal of IEEE 802.16m has two kinds of A-Preambles: the PA-Preamble and the SA-Preamble. This paper proposes the effective method of estimating SNR and SINR with A-Preambles, and also shows that this method can recognize the ICI(Inter-Carrier-Interference) occurrence due to doppler frequency. With the recognition of ICI, the mobile station can save the power by operating 1-tap equalizer in usual cases, and activating ICI mitigation module only when it perceives the ICI occurrence.
Anti-jamming Performance Analysis of Link-16 Waveform
Noh, Hong-Jun ; Kim, Jung-Bin ; Lim, Jae-Sung ; Nam, Jeong-Ho ; Jang, Dhong-Woon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 12A, 2010, Pages 1105~1112
Link-16 is a up-to-date tactical data link used in the armed forces of U.S. and NATO. In order to guarantee the required capabilities of anti-jamming and low probability of detection, Link-16 uses the techniques of frequency hopping and spreading code etc. In this paper, under Nakagami fading channels, we ananlyze the symbol error rates (SERs) of JTIDS/Link-16-type waveform based on both the single- and double-pulse schemes by considering the partial band noise jamming and the pulse jamming models, respectively.
A Robust Scheme for Emergency Message Delivery in Vehicle Communications on Freeway
Park, Jeong-Seo ; Park, Tae-Keun ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 12A, 2010, Pages 1113~1121
The Vehicle Safety Communications (VSC) is one of VANET applications for preventing vehicle accidents, and it utilizes vehicle-to-vehicle communication to exchange emergency messages. To propagate such messages in VSC, several schemes based on selective flooding have been proposed. Their common idea is that an emergency message is relayed by one of vehicles receiving the message. However, the schemes do not consider the transmission errors and duplications of an emergency event. In the schemes, if there are transmission errors and a vehicle detects a hazard, there may be vehicles which fail to receive an emergency message. If k vehicles detect a hazard, k emergency messages are created and propagated. The duplications of an event increase reliability of the message delivery but decrease efficiency. In this paper, we propose an emergency message delivery scheme which is efficient and robust to transmission errors. Our proposed scheme utilizes clustering for massage aggregation and retransmissions in a cluster. It also uses an acknowledgment mechanism for reliable inter-cluster communication. Our simulation results show that the proposed scheme outperforms Least Common Neighbor Flooding which is one of the selective flooding schemes.
Relay-based Cooperative Communication Technique using Repetitive Transmission on D-STBC
Song, Ki-O ; Jung, Yong-Min ; Jung, Hyeok-Koo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 12A, 2010, Pages 1122~1127
In this paper, we propose a relay-based DF cooperative communication scheme using repetitive transmission algorithm for wireless LAN environments on D-STBC. Additional transmission diversity gain can be obtained by repetitive transmission algorithm. However, in comparison with conventional schemes, data rate is decreased in half. We consider data modulation constellation twice higher than conventional schemes. Further, system complexity is decreased and performance degradation is minimized because repetitive transmission algorithm is adapted between source and relay node. We show the uncoded BER performance of the proposed algorithm over HiperLAN/2 Rayleigh fading channel.
A Study on UWB Ranging and Positioning Technique using Common Clock
Park, Jae-Wook ; Choi, Yong-Sung ; Lee, Soon-Woo ; Lee, Won-Cheol ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 12A, 2010, Pages 1128~1135
A wireless positioning system using ultra-wideband (UWB) for indoor wireless positioning uses ranging data in order to accurately estimate location. Commonly, ranging uses time of arrival (TOA), time difference of arrival (TDOA) based on arrival time. The most fundamental issue in the ranging for wireless positioning is to obtain clock synchronization among the sensor nodes and to correct an error caused by the relative clock offset from each node. In this paper, we propose ranging and positioning technique using common clock in order to solve both clock synchronization and clock offset problems. To verify the performance of proposed, we simulated ranging and positioning in channel model introduced by IEEE 802.15.4a Task Group and then results show that location estimation is unaffected by clock offset.
Performance Improvement of ARQ Protocol using HARQ Feedback Information in IEEE 802.16m Systems
Lee, Jong-Min ; Hong, Dae-Hyoung ; So, Jae-Woo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 12A, 2010, Pages 1136~1144
In this paper, the effects of HARQ feedback error are evaluated in IEEE 802.16m system when the HARQ and ARQ interactions that utilize the HARQ feedback information is used. Also, the HARQ and ARQ interaction scheme considering HARQ feedback errors are proposed. The HARQ and ARQ interaction scheme improve the system throughput by using the HARQ feedback information instead of the ARQ feedback message, which reduce retransmission time. However, errors in the HARQ feedback information generate severe performance degradation. Especially, the local NAK errors between HARQ feedback error critically degrade the performance, because the local NAK errors lead the loss of ARQ blocks. We propose a channel state-based schemes for HARQ and ARQ interactions to mitigate the throughput degradation due to HARQ feedback errors. Simulation results show that the proposed scheme improves the throughput and the delay performance.
On the Relationship Between the Performance Criteria of Unitary Space-Time Codes with Noncoherent and Coherent Decoding
Cheun, Kyung-Whoon ; Kim, Jeong-Chang ; Choi, Soong-Yoon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 12A, 2010, Pages 1145~1151
Hochwald et al. introduced unitary space-time codes for quasi-static Rayleigh fading channels which allows for noncoherent decoding when the channel response is not known at the receiver. However, when reliable information on the channel response is available, coherent decoding is preferable for improved performance. Here, we study the relationship between the performance criteria on the diversity and coding advantages provided by unitary space-time codes with noncoherent and coherent decoding. We show that when a unitary space-time code achieves full spatial diversity with noncoherent decoding, full spatial diversity is also guaranteed with coherent decoding.
A Rate Separating Multi-Channel Protocol for Improving Channel Diversity and Node Connectivity in IEEE 802.11 Mesh Networks
Kim, Sok-Hyong ; Suh, Young-Joo ; Kwon, Dong-Hee ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 12A, 2010, Pages 1152~1159
Wireless Mesh Networks (WMNs) provides Internet accesses to users by forming backbone networks via wireless links. A key problem of WMN is network capacity. For this, multi-channel and multi-rate functions of IEEE 802.11 can be utilized. Depending on channel assignments, multi-channel determines node connectivity and channel diversity. Also, in IEEE 802.11 multi-rate networks, the rate anomaly problem occurs, the phenomenon that low-rate links degrades the performance of high-rate links. In this paper, we propose rate separating multi-channel (RSMC) protocols that improves the node connectivity and channel diversity, and mitigates the rate anomaly problem. RSMC increases the channel diversity by forming tree-based WMNs and decreases the rate anomaly by separating different rate links on the tree via channels. In addition, it uses network connectivity (NC) algorithm to increase the node connectivity. Through simulations, we demonstrate that the RSMC shows improved performance than existing multi-channel protocols in terms of aggregate throughput, node connectivity, channel diversity.
An Energy Efficient Explicit Disjoint Multipath Routing in Wireless Sensor Networks
Oh, Hyun-Woo ; Jang, Jong-Hyun ; Moon, Kyeong-Deok ; Kim, Sang-Ha ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 12A, 2010, Pages 1160~1170
Existing multipath routing mechanism has much overhead to maintain the state of nodes on the multipath route and does not guarantees completely disjoint multipath construction from source to destination. In this paper, we propose an Explicit Disjoint Multipath (EDM) routing algorithm to enhance energy efficiency through removing the flooding mechanism for route discovery process, minimizing the number of nodes participating in route update and balancing the traffic load for entire network. EDM constructs logical pipelines which can create disjoint multipaths in logical way. Then it physically performs anchor node based geographic routing along the logical pipeline in order to build multipath to the destination. EDM can provide the distribution effect of traffic load over the network, help to balance the energy consumption and therefore extend the network lifetime.
Reliable Continuous Object Detection Scheme in Wireless Sensor Networks
Nam, Ki-Dong ; Park, Ho-Sung ; Yim, Young-Bin ; Oh, Seung-Min ; Kim, Sang-Ha ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 12A, 2010, Pages 1171~1180
In wireless sensor networks, reliable event detection is one of the most important research issues. For the reliable event detection, previous works usually assume the events are only individual objects such as tanks and soldiers. Recently, many researches focus on detection of continuous objects such as wild fire and bio-chemical material, but they merely aim at methods to reduce communication costs. Hence, we propose a reliable continuous object detection scheme. However, it might not be trivial. Unlike individual objects that could be referred as a point, a continuous object is shown in a dynamic two-dimensional diagram since it may cover a wide area and it could dynamically alter its own shape according to physical environments, e.g. geographical conditions, wind, and so on. Hence, the continuous object detection reliability can not be estimated by the indicator for individual objects. This paper newly defines the reliability indicator for continuous object detection and proposes an error recovery mechanism relying on the estimation result from the new indicator.
A Neural Network-based Artificial Intelligence Algorithm with Movement for the Game NPC
Joe, In-Whee ; Choi, Moon-Won ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 12A, 2010, Pages 1181~1187
This paper proposes a mobile AI (Artificial Intelligence) conducting decision-making in the game through education for intelligent character on the basis of Neural Network. Neural Network is learned through the input/output value of the algorithm which defines the game rule and the problem solving method. The learned character is able to perceive the circumstances and make proper action. In this paper, the mobile AI using Neural Network has been step-by-step designed, and a simple game has been materialized for its functional experiment. In this game, the goal, the character, and obstacles exist on regular 2D space, and the character, evading obstacles, has to move where the goal is. The mobile AI can achieve its goals in changing environment by learning the solution to several problems through the algorithm defined in each experiment. The defined algorithm and Neural Network are designed to make the input/output system the same. As the experimental results, the suggested mobile AI showed that it could perceive the circumstances to conduct action and to complete its mission. If mobile AI learns the defined algorithm even in the game of complex structure, its Neural Network will be able to show proper results even in the changing environment.
Load-balanced Topology Maintenance with Partial Topology Reconstruction
Hong, Youn-Sik ; Lim, Hwa-Seok ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 12A, 2010, Pages 1188~1197
A most important thing in a connected dominating set(CDS)-based routing in a wireless ad-hoc network is to select a minimum number of dominating nodes and then build a backbone network which is made of them. Node failure in a CDS is an event of non-negligible probability. For applications where fault tolerance is critical, a traditional dominating-set based routing may not be a desirable form of clustering. It is necessary to minimize the frequency of reconstruction of a CDS to reduce message overhead due to message flooding. The idea is that by finding alternative nodes within a restricted range and locally reconstructing a CDS to include them, instead of totally reconstructing a new CDS. With the proposed algorithm, the resulting number of dominating nodes after partial reconstruction of CDS is not changed and also its execution time is faster than well-known algorithm of construction of CDS by 20~40%. In the case of high mobility situation, the proposed algorithm gives better results for the performance metrics, packet receive ratio and energy consumption.
Effective Frequency Reuse Scheme for OFDMA Cellular Multihop Networks for Improving Cell Throughput with Low Outage Ratio
Lim, Sung-Gook ; Jeon, Hahn-Earl ; Lee, Jai-Yong ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 12A, 2010, Pages 1198~1206
Recently smart phone and tablet PC are regarded as the most valuable mobile devices, so the demand of customers for multimedia supporting has been greatly increased. The network operators are now considering the deployment of relay stations ensuring low installation costs for its service cell to improve the cell capacity. Enhancing the relay stations, however, increases intra-cell interference, which is affecting the quality of service and outage ratio. In this paper, we present MPFR(Multihop Partial Frequency reuse) as the new frequency reuse scheme to increase cell throughput while maintaining low outage ratio for the OFDMA cellular multihop networks. Dynamic power control is also introduced to improve cell capacity. Overall cell throughput and outage ratio are observed by the simulation, and comparison between MPFR and conventional multihop frequency reuse schemes is convincing the performance enhancement.
A Study on Additional Data Transmission Scheme Based on T-DMB System for Emergency Broadcasting Service
Cha, Jae-Sang ; Bae, Jung-Nam ; Lee, Kyong-Gun ; Kim, Geon ; Lee, Yong-Tae ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 12A, 2010, Pages 1207~1213
In this paper, we proposed analysis additional data transmission scheme based on T-DMB system with watermarking technique for emergency broadcasting service. By applying the proposed scheme to T-DMB system, it allows additional data transmission and improves spectral efficiency of data transmission through watermarking spreading code. In the emergency situation, we can react the emergency situation using the emergency information that generated by proposed scheme. We are certified availability of our proposed technology by using various simulation. The performance is evaluated in terms of bit error rate (BER). From the simulation result, we confirmed the performance of T-DMB system embedded watermarking scheme and it is shown that system performance is affected the watermarking level. The results of the paper can be applied to wireless multimedia digital broadcasting system.
The Implementation of UWB Bandpass Filter using SIR(Stepped Impedance Resonators) Structure
Shin, Seung-Ha ; Choi, Chang-Ho ; Jun, Kye-Suk ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 12A, 2010, Pages 1214~1218
A new compact UWB bandpass filter with sharp-rejection and low insertion-loss is designed in this paper, using the parallel transmission line with SIR structure. An Example filter is firstly theoretically designed by the proposed synthesis procedure, the optimized by EM simulator, fabricated in microstrip line and finally characterized by a network analyzer. A good agreement between the simulation results and prototype validates the proposed UWB bandpass filter. The designed filter also realized a sharp rejection of higher order with a relatively small size which is proper for the UWB communication system.