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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
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Novel Pilot-Assisted Channel Estimation Techniques for 3GPP LTE Downlink with Performance-Complexity Evaluation
Qin, Yang ; Hui, Bing ; Chang, Kyung-Hi ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 7A, 2010, Pages 623~631
In this paper, various of pilot-assisted channel estimation techniques for 3GPP LTE downlink are tested under multipath Rayleigh fading channel. At first, the conventional channel estimation techniques are applied with linear zero-forcing (ZF) equalizer, such as one dimensional least square (1-D LS) linear interpolation, two dimensional (2-D) wiener filter, the time and frequency dimension separate wiener filter and maximum likelihood estimator (MLE). Considering the practical implementation, we proposed two channel estimation techniques by combining time-dimension wiener filter and MLE in two manners, which showed a good tradeoff between system performance and complexity when comparing with conventional techniques. The nonlinear decision feedback equalizer (DFE) which can show a better performance than linear ZF equalizer is also implemented for mitigating inter-carrier interference (ICI) in our system. The complexity of these algorithms are calculated in terms of the number of complex multiplications (CMs) and the performances are evaluated by showing the bit error rate (BER).
Fixed-complexity Sphere Encoder for Multi-user MIMO Systems
Mohaisen, Manar ; Han, Dong-Keol ; Chang, Kyung-Hi ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 7A, 2010, Pages 632~638
In this paper, we propose a fixed-complexity sphere encoder (FSE) for multi-user MIMO (MU-MIMO) systems. The Proposed FSE accomplishes a scalable tradeoff between performance and complexity. Also, because it has a parallel tree-search structure, the proposed encoder can be easily pipelined, leading to a tremendous reduction in the precoding latency. The complexity of the proposed encoder is also analyzed, and we propose two techniques that reduce it. Simulation and analytical results demonstrate that in a
MU-MIMO system, the complexity of the proposed FSE is 16% that of the conventional QRD-M encoder (QRDM-E). Also, the encoding throughput of the proposed endoder is 7.5 times that of the QRDM-E with tolerable degradation in the BER performance, while achieving the optimum diversity order.
Selection Relaying Scheme Based Geographic Information with Imperfectly Decoding Relays in ARQ protocols
Xuyen, Tran Thi ; Kong, Hyung Yun ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 7A, 2010, Pages 639~645
In the paper, a selection relaying scheme is proposed and analyzed in which relays retransmit the erroneous packet without checking the correctness of their received packets. The proposal not only achieves the full diversity gain in a limited number of retransmissions but it also gets better performance than other schemes. Additionally, a threshold in the number of retransmissions and the closed form expression for packet error rate (PER) are derived. Simulation results are given to confirm the accuracy of analysis and to significantly prove advantages of the proposal.
A Unified Framework for Joint Optimal Design of Subchannel Matching and Power Allocation in Multi-hop Relay Network
Jang, Seung-Hun ; Kim, Dong-Ku ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 7A, 2010, Pages 646~653
This paper provides a unified framework for the joint optimal subchannel and power allocation in multi-hop relay network, where each node in the network has multiple parallel subchannels such as in OFDM or MIMO system. When there are multiple parallel subchannels between nodes, the relay node decides how to match the subchannel at the first hop with the one at the second hop aside from determining the power allocation. Joint optimal design of subchannel matching and power allocation is, in general, known to be very difficult to solve due to the combinatorial nature involved in subchannel matching. Despite this difficulty, we use a simple rearrangement inequality and show that seemingly difficult problems can be efficiently solved. This includes several existing solution methods as special cases. We also provide various design examples to show the effectiveness of the proposed framework.
Frequency allocation method for an inter-cell interference management on 3GPP LTE systems
Cho, Kyong-Kuk ; Kim, Sang-Goo ; Yoon, Dong-Weon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 7A, 2010, Pages 654~659
In this paper, we propose a new frequency allocation method for improvement of edge and low 5% user throughputs. Although many kinds of inter cell interference mitigation methods have been proposed, those have still high complexity of implementation. The proposed algorithm has lower complexity and higher edge user throughput than conventional algorithms since the same frequency allocation method is applied in all cell. Finally, we analyze and compare the edge and low 5% user throughputs using a system level simulation (SLS).
An Efficient Power Allocaction Scheme to Maximize Network Lifetime in Wireless Relay Networks with Energy Contraint
Park, Dae-Jun ; Kim, Hyung-Myung ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 7A, 2010, Pages 660~668
In energy resource constrained networks, the network lifetime can be enhanced by optimally allocating energy resource among users based on the available channel state information and the residual energy information at each node. In this paper, we propose the relay selection scheme and power allocation scheme to maximize the network lifetime in wireless relay networks with capacity constraint. The computer simulation results show that the proposed scheme increase the network lifetime in comparison to the conventional schemes.
UWB-based Class 4 Active RFID Protocol for USN Application
Hong, Sung-Hyun ; Zhang, Hong ; Chang, Kyung-Hi ; Shin, Dong-Beom ; Lee, Heyung-Sub ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 7A, 2010, Pages 669~681
In this paper, we analyze the active RFID system ISO/IEC 18000-7. In order to apply to USN, which consists active RFID tags and sensor nodes, we propose UWB-based Class 4 active RFID protocol using active RFID relay tag as relay AP. To compare the performance between the existing ISO/IEC 18000-7 system and the proposed system, we introduce sensitivity-based measurement of achieved coverage and system efficiency. Also, we analyze the performance of the proposed system and compare it with that of the existing system through MCL analysis and SLS analysis.
Novel Multiple Access Schemes for IEEE 802.15.4a Low-rate Ultra-wide Band Systems
Zhang, Hong ; Hui, Bing ; Chang, Kyung-Hi ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 7A, 2010, Pages 682~687
The IEEE 802.15.4a specification targets the low-rate (LR) Impulse-radio (IR) ultra-wideband (UWB) system which is now widely applied in the WPANs considering rather short distance communications with low complexity and power consumption. The physical (PHY) layer uses concatenated coding with mixed binary phase-shift keying and binary pulse-position modulation (BPSK-BPPM), and direct sequence spreading with time hopping in order that both coherent and non-coherent receiver architectures are supported. In this paper, the performances of multiple access schemes compliant with IEEE 802.15.4a specification are investigated with energy detection receiver, which allow avoiding the complex channel estimation needed by a coherent receiver. However, the performance of energy detection receiver is severely degraded by multi-user interference (MUI), which largely diminishes one of the most fascinating advantages of UWB, namely robustness to MUI as well as the possibility to allow parallel transmissions. So as to improve the performance of multiple access schemes, we propose to apply the novel TH sequences as well as to increase the number of TH positions. The simulation results show that our novel multiple access schemes significantly improve the performance against MUI.
Global Mobility Support in Network Based Proxy Mobile IPv6
Phung, Gia Khiem ; Ro, Soong-Hwan ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 7A, 2010, Pages 688~696
The Proxy Mobile IPv6 (PMIPv6) is a network localized mobility management protocol that is independent of global mobility management protocols. In a single mobility domain (LMD), the mobile node (MN) is not involved in any IP mobility-related signaling and uses only its PMIPv6 home address for all its communication. Subsequently, when the MN moves into another LMD, the MN must change its PMIPv6 home address. In such a circumstance, host-based mobility signaling is activated. Thus, the nature of the network-based mobility of the PMIPv6 cannot be retained. Additionally, if the MN does not support global mobility, it cannot maintain communication with its correspondent node (CN). In this paper, we propose a solution for global mobility support in PMIPv6 networks, called Global-PMIPv6 that allows current communication sessions of a MN without mobility protocol stacks to be maintained, even when the MN moves into another LMD. Thus, Global-PMIPv6 retains the advantages of the PMIPv6 for global mobility support. We then evaluate and compare network performance between our proposed solution and PMIPv6.
Impact of Sensing Models on Probabilistic Blanket Coverage in Wireless Sensor Network
Pudasaini, Subodh ; Kang, Moon-Soo ; Shin, Seok-Joo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 7A, 2010, Pages 697~705
In Wireless Sensor Networks (WSNs), blanket (area) coverage analysis is generally carried to find the minimum number of active sensor nodes required to cover a monitoring interest area with the desired fractional coverage-threshold. Normally, the coverage analysis is performed using the stochastic geometry as a tool. The major component of such coverage analysis is the assumed sensing model. Hence, the accuracy of such analysis depends on the underlying assumption of the sensing model: how well the assumed sensing model characterizes the real sensing phenomenon. In this paper, we review the coverage analysis for different deterministic and probabilistic sensing models like Boolean and Shadow-fading model; and extend the analysis for Exponential and hybrid Boolean-Exponential model. From the analytical performance comparison, we demonstrate the redundancy (in terms of number of sensors) that could be resulted due to the coverage analysis based on the detection capability mal-characterizing sensing models.
Restricted Multi-hop Information Lookahead Scheme for Real-Time Data Dissemination in Wireless Sensor Networks
Jung, Ju-Hyun ; Oh, Seung-Min ; Lee, Jeong-Cheol ; Park, Ho-Sung ; Yim, Yong-Bin ; Kim, Sang-Ha ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 7A, 2010, Pages 706~714
In wireless sensor networks, real-time data delivery schemes typically achieve a desired delivery speed by performing one-hop lookahead. Recently, to reduce the deadline miss ratio against the desired delivery speed, a study has proposed a real-time routing protocol based on proactively performing two-hop lookahead. However, the study might cause heavy message exchange overhead and high computing complexity to carry out obtainment of two-hop neighborhood speed information in the entire sensor nodes whether data are delivered or not. Moreover, although multi-hop lookahead provides the least deadline miss ratio, due to the restriction from the overhead and the complexity, the recent study merely adopts the two-hop lookahead manner. In this paper, we propose a novel real-time routing protocol that adopts on-demand neighborhood multi-hop information obtainments only around data forwarding paths. Simulation results prove that the proposed routing protocol offers better performances with respect to deadline miss ratio, total communication costs, energy efficiency, and network lifetime.
The Construction and Performance Test of High-Speed Satellite Network Pilot System for Hydrological observations
Hong, Sung-Teak ; Shin, Gang-Wook ; Jang, Sung-Woon ; Park, Seong-Soo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 7A, 2010, Pages 715~724
K-water has used satellite networks for 12 years for hydrological observation in various parts such as remote data acquisition and providing information including flood forecasting. It is the time to replace equipments according to long-term use of the system. A pilot system for high speed satellite networks is implemented by seven terminals, three 2-hops and 1 hub in Ku-Band bandwidth by using VSAT. According to the result for the performance test on the system, the result fot all items, including Link Budget designed meets performance levels.
Calculation of Effective Receiving Electric Field Level using the Measurement Analysis from Actual Domestic DTV Environment
Choi, Sung-Woong ; Lee, Kyung-Ryang ; Yang, Chung-Mo ; Kim, Seong-Kweon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 7A, 2010, Pages 725~730
Preparing the conversion to the digital broadcasting system, we are deciding broadcasting network plan and interference protection area, using the measured receiving electric field level from the digital broadcasting station. However, the essential researches are needed about a receiving electric field level, because a digital TV (DTV) broadcasting receiver has been improved and an actual receiving environment should be considered. In this paper, the measured data were classified with domestic terrain of line of sight (LOS) and those of non-LOS, and effective receiving electric field level was proposed based on the LOS data. It is known that receiving electric field-level of 48 ㏈uV/m or more should be required for receiving rate of 90% and 50 ㏈uV/m for that of 95%, on the basis of the information of domestic terrain LOS.
On the Performance of Incremental Opportunistic Relaying with Differential Modulation over Rayleigh Fading Channels
Bao, Vo Nguyen Quoc ; Kong, Hyung-Yun ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 7A, 2010, Pages 731~742
We propose an incremental relaying protocol in conjunction with opportunistic communication for differential modulation with an aim to make efficient use of the degrees of freedom of the channels by exploiting a imited feedback signal from the destination. In particular, whenever the direct link from the source to the destination is not favorable to decoding, the destination will request the help from the opportunistic relay (if any). The performance of the proposed system is derived in terms of average bit error probability and achievable spectral efficiency. The analytic results show that the system assisted by the opportunistic relaying can achieve full diversity at low SNR regime and exhibits a 30㏈ gain relative to direct transmission, assuming single-antenna terminals. We also determine the effect of power allocation on the bit error probability BEP) performance of our relaying scheme. We conclude with a discussion on the relationship between the given thresholds and channel resource savings. Monte-Carlo simulations are performed to verify the analysis.