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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 32, Issue 12C - Dec 2007
Volume 32, Issue 12B - Dec 2007
Volume 32, Issue 12A - Dec 2007
Volume 32, Issue 11C - Nov 2007
Volume 32, Issue 11B - Nov 2007
Volume 32, Issue 11A - Nov 2007
Volume 32, Issue 10C - Oct 2007
Volume 32, Issue 10B - Oct 2007
Volume 32, Issue 10A - Oct 2007
Volume 32, Issue 9C - Sep 2007
Volume 32, Issue 9B - Sep 2007
Volume 32, Issue 9A - Sep 2007
Volume 32, Issue 8C - Aug 2007
Volume 32, Issue 8B - Aug 2007
Volume 32, Issue 8A - Aug 2007
Volume 32, Issue 7C - Jul 2007
Volume 32, Issue 7B - Jul 2007
Volume 32, Issue 7A - Jul 2007
Volume 32, Issue 6C - Jun 2007
Volume 32, Issue 6B - Jun 2007
Volume 32, Issue 6A - Jun 2007
Volume 32, Issue 5C - May 2007
Volume 32, Issue 5B - May 2007
Volume 32, Issue 5A - May 2007
Volume 32, Issue 4C - Apr 2007
Volume 32, Issue 4B - Apr 2007
Volume 32, Issue 4A - Apr 2007
Volume 32, Issue 3C - Mar 2007
Volume 32, Issue 3B - Mar 2007
Volume 32, Issue 3A - Mar 2007
Volume 32, Issue 2C - Feb 2007
Volume 32, Issue 2B - Feb 2007
Volume 32, Issue 2A - Feb 2007
Volume 32, Issue 1C - Jan 2007
Volume 32, Issue 1B - Jan 2007
Volume 32, Issue 1A - Jan 2007
Selecting the target year
The Flexible Design of 0.96 Tbps WDM System over 1,000km NZ-DSF by Using Optimal Parameters of Optical Phase Conjugator
Lee, Seong-Real ; Doh, Kyu-Bong ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 7A, 2007, Pages 657~665
In this paper, it is investigated that the limitation due to the asymmetry of optical power and chromatic dispersion with respect to optical phase conjugator (OPC) for compensating optical signal distortion of WDM channels in mid-span spectral inversion (MSSI) technique is overcame by using OPC position offset and optimal dispersion coefficients of fiber sections, which depend on OPC position offset. It is confirmed that overall WDM channels are efficiently compensated by applying the optimal parameter values obtained from the proposed method into 24 channels
WDM system with non zero - dispersion shifted fiber (NZ-DSF) of 1,000 km, such as power penalties of inter-channel are reduce to almost 3.5 dB from the infinite value. It is also confirmed that the flexible design of WDM system with OPC is possible by using the optimal parameters, in which OPC is placed at
from 500 km for efficiently compensating overall channels.
Application of EPON to Wireless Network and Handover Algorithm
Cho, Won-Kuk ; Chung, Jun-Hoi ; Park, Jae-Uk ; Choi, Byung-Chul ; Park, Young-Il ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 7A, 2007, Pages 666~671
EPON is proposed to be used in an infrastructure of the next generation wireless network. EPON can reduce fiber deployment cost and easily decrease the occurrence of layer-3 handover by introducing group cell concept. An EPON-based layer-2 handover algorithm is suggested for fast handover. The time-delay of the control signals are examined using simulation.
Automatic Off Level Biasing for Electro Optic Mach-Zehnder Modulator
Yang, Choong-Reol ; Ko, Je-Soo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 7A, 2007, Pages 672~677
A novel method for stabilizing the bias of an Electro-Optic Mach-Zehnder modulator has been proposed and demonstrated to maximize the switching extinction ratio in burst mode packet traffic. By sampling and minimizing the off-level output power of the modulator, a high extinction optical gate switch in obtain regardless of the variation of the packet traffic density.
An Implementation of the Network Synchronization Equipment on Optical Transmission Flatform and Impact Analysis of the Wander on NG-SDH Network
Yang, Choong-Reol ; Ko, Je-Soo ; Lee, Chang-Ki ; Kim, Whan-Woo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 7A, 2007, Pages 678~685
We implemented the network synchronization equipment for the optical transmission platform or next generation Packet/TDM(Time Division Multiplexing) data converged switching system and then, presented an impact of wander generation on the NG-SDH optical transmission network.
Setting Up/Down Step-Size in Open Loop Power Control for WiBro Reverse Link
Guk, Hyun ; Kim, Jung-Bin ; Kim, Dong-Woo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 7A, 2007, Pages 686~693
In this paper, we describe how to set up/down step-size in open loop power control for WiBro reverse link. Since open loop power control does not use feedback information, it is difficult to efficiently use wireless resource with accurate power control. We also provides a method of estimating levels of noise and interference. With numerical investigation, asymmetric up/down power-control step-size is shown to be promising to achieve high sector throughput as well as low error rate.
On the Optimal Antenna Weighting Method for Closed-Loop Transmit Antenna Diversity with Average and Peak Power Constraints
Lee, Ye-Hoon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 7A, 2007, Pages 694~699
We consider an optimal antenna weighting scheme for a closed-loop transmit antenna diversity system in Rayleigh fading channels. We derive a closed-form expression for the optimal transmitter weights that minimize the average bit error rate (BER) subject to fixed average and peak transmit power constraints. It is shown that the peak power limitation degrades the average BER performance more significantly as the available average power and/or the number of transmit antennas increase.
TCP Congestion Control based on Context Switch in Heterogeneous Wireless Networks
Seok, Woo-Jin ; Choi, Young-Hwan ; Park, Gui-Soon ; Na, Jee-Hyeon ; Kim, Sang-Ha ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 7A, 2007, Pages 700~709
The heterogeneous wireless access networks has been envisioned to characterize the future wireless networks. In such environments, TCP(Transmission Control Protocol) has to experience poor end-to-end performance because bandwidth and link delay change suddenly when a mobile node moves over different types of wireless networks, which is called vertical handoff. In this paper, we propose a new TCP which maintains each set of congestion control variables, which we call TCP context, for each type of wireless network. The proposed TCP can switch the TCP context against vertical handoff in order to adjust quickly to a newly arrived network. In simulations, the proposed TCP has higher throughput than TCP SACK(Selective Acknowledgment Options) due to its great features to vertical handoff situations.
Co-Channel Interference Cancellation in Cellular OFDM Networks PART II: Co-Channel Interference Cancellation in Single Frequency OFDM Networks using Soft Decision MLE CCI Canceler
Mohaisen, Manar ; Chang, Kyung-Hi ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 7A, 2007, Pages 710~716
In this paper, a new scheme of downlink co-channel interference (CCI) cancellation in OFDM cellular networks is introduced for users at the cell-edge. Coordinated symbol transmission between base stations (BS) is operated where the same symbol is transmitted from different BS on different sub-carriers. At the mobile station (MS) receiver, we introduce a soft decision maximum likelihood CCI canceler and a modified maximum ratio combining (M-MRC) to obtain an estimate of the transmitted symbols. Weights used in the combining method are derived from the channels coefficients between the cooperated BSs and the MS. Simulations show that the proposed scheme works well under frequency-selective channels and frequency non-selective channels. A gain of 9 dB and 6 dB in SIR is obtained under multipath fading and flat-fading channels, respectively.
Efficient Security Mechanism using Light-weight Data Origin Authentication in Sensor Networks
Park, Min-Ho ; Lee, Chung-Keun ; Son, Ju-Hyung ; Seo, Seung-Woo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 7A, 2007, Pages 717~723
There are many weaknesses in sensor networks due to hardware limitation of sensor nodes besides the vulnerabilities of a wireless channel. In order to provide sensor networks with security, we should find out the approaches different from ones in existing wireless networks; the security mechanism in sensor network should be light-weighted and not degrade network performance. Sowe proposed a novel data origin authentication satisfying both of being light-weighted and maintaining network performance by using Unique Random Sequence Code. This scheme uses a challenge-response authentication consisting of a query code and a response code. In this paper, we show how to make a Unique Random Sequence Code and how to use it for data origin authentication.
Joint Tx-Rx Optimization in Additive Cyclostationary Noise with Zero Forcing Criterion
Yun, Yeo-Hun ; Cho, Joon-Ho ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 7A, 2007, Pages 724~729
In this paper, we consider a joint optimization of transmitter and receiver in additive cyclostationary noise with zero forcing criterion. We assume that the period of the cyclostationary noise is the same as the inverse of the symbol transmission rate and that the noise has a positive-definite autocorrelation function. The data sequence is modeled as a wide-sense stationary colored random process and the channel is modeled as a linear time-invariant system with a frequency selective impulse response. Under these assumptions and a constraint on the average power of the transmitted signal, we derive the optimum transmitter and receiver waveforms that jointly minimizes the mean square error with no intersymbol interference. The simulation results show that the proposed system has a better BER performance than the systems with receiver only optimization and the systems with no transmitter and receiver optimization.
Calculation of TDD-based Occupied Frequency Bandwidth in Technique Criteria for 4G Mobile Communication
Hyun, Young-Ju ; Lee, Young-Hwan ; Jang, Dong-Won ; Kim, Kyung-Seok ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 7A, 2007, Pages 730~737
The new wireless multimedia environment is coming because of the variety of an user requirement and a traffic increase which we can not accept in the IMT-2000 present systems. To offer the wireless multimedia service the world wireless communication company which included the ITU-R is developing the standard and technique of 4G systems. We analyzed the technique criteria of the 4G wireless communication system in this paper which is based on that of WiBro System. We referred to the technique criteria of the WiBro system and deduced an occupied frequency bandwidth which is the common element of the uplink and downlink system among main wireless communication technique criteria. And we verified this through the simulation. So we proposed the occupied frequency bandwidth for 4G wireless communication in this paper.
SER Analysis of Arbitrary Two-Dimensional Signaling over Nonlinear AWGN Channels
Lee, Jae-Yoon ; Yoon, Dong-Weon ; Cho, Kyong-Kuk ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 7A, 2007, Pages 738~745
The non-linearity of HPA(high power amplifier) which is an important component in modern communications systems introduces AM/AM and AM/PM distortion so that the transmitted signal is deteriorated. And, the I/Q unbalances and phase error which are generated by non-ideal components are inevitable physical phenomena and lead to performance degradation when we implement a practical two-dimensional (2-D) modulation system. In this paper, we provide an exact and general expression involving the 2-D Gaussian Q-function for the error probabilities of arbitrary 2-D signaling with I/Q amplitude and phase unbalances in nonlinear additive white Gaussian noise (AWGN) channels by using the coordinate rotation and shifting technique.
Fast Micro-mobility Management Scheme without DAD Session in HMIPv6 Networks
Lee, Sung-Kuen ; Kim, Eal-Lae ; Lim, Tae-Hyung ; Jeong, Seok-Jong ; Park, Jin-Woo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 7A, 2007, Pages 746~754
In this paper, we propose a fast handoff algorithm for micromobility management enhancement in HMIPv6 networks, which eliminates the DAD procedure involved in the regular HMIPv6 in order to o decrease handoff latency and increase the resource utilization efficiency. In the proposed scheme, the MAP is designed to guarantee the uniqueness of MN's interface identifier within a MAP domain as long as the MN moves in a MAP domain, so that the MN configures the new address without the DAD procedure resulting in the decreased handoff latency significantly When the MN resides in a subnet, MIPv6 is used adaptively as a mobility management protocol, which is to reduce bandwidth waste from the IP packet header overhead of IP-in-IP tunneling from the regular HMIPv6. We evaluate the performance of the proposed handoff micromobility algorithm in terms of handoff delay and packet loss thru computer simulation. Thru various computer simulation results, we verified the superior performance of the proposed scheme by comparing with the results of other schemes, MIPv6 and HMIPv6.
Performance Analysis of Wireless Internet System of WiBro Employing the Uplink Single Carrier Scheme
Kim, Jeong-Ho ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 7A, 2007, Pages 755~761
In this paper the uplink single carrier scheme is proposed for wireless Internet application and its performance is evaluated in terms of PAPR (peak to average power ratio) and ABR (achievable bit rate) compared with the uplink OFDM scheme. There exist constraints regarding the signal amplification because the non-linear amplifier should be exploited instead of the linear amplifier due to its high cost of linear amplifier and power inefficiency at the WiBro terminal. Therefore characteristics in the uplink scheme design are discussed in order to maximize ABR and relieve the requirements for the amplifier specifications.
A Robust Adaptive MIMO-OFDM System Over Multipath Transmission Channels
Kim, Hyun-Dong ; Choe, Sang-Ho ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 7A, 2007, Pages 762~769
Adaptive MIMO-OFDM (Orthogonal Frequency Division Multiplexing) system adaptively changes modulation scheme depending on feedback channel state information (CSI). The CSI feedback channel which is the reverse link channel has multiple symbol delays including propagation delay, processing delay, frame delay, etc. The unreliable CSI due to feedback delay degrades adaptive modulation system performance. This paper compares the MSE and data capacity with respect to delay and channel signal to noise ratio for the two multi-step channel prediction schemes, CTSBP and BTSBP, such that robust adaptive SISO-OFDM/MIMO-OFDM is designed over severe mobile multipath channel conditions. This paper presents an interpolation method to reduce feedback overhead for adaptive MIMO-OFDM and shows MSE with respect to interpolation interval.
A Handover Method for Service Continuity of Mobile Multimedia
Lee, Jong-Chan ; Lee, Moon-Ho ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 7A, 2007, Pages 770~777
Smaller cell size in the micro-cell or pico-cell structure brings about more frequent hand-overs between cells, and higher speed movement of the mobile terminal makes short the permissible time interval for executing these hand-over procedures. In this situation the hand-over failure may occur or some packets may be lost during the hand-over. Moreover a rapid degradation of throughput is triggered by packet re-transmission for compensating such errors. The QoS (Quality of Services) of mobile multimedia applications with higher bits rate requirements and higher speed mobility are severely affected by even shot service interruption. This paper proposes a new hand-over scheme to provide seamless services in the next generation mobile communication systems. Simulation is done to evaluate the performance of the proposed scheme based on its hand-over failure rate and packet loss rate.
Prediction Accuracy Enhancement Based on Adaptive Reporting Schemes of Mobile's Mobility Status Information
Ko, Yong-Chae ; Bae, Jung-Hwa ; Park, Jin-Woo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 7A, 2007, Pages 778~784
Predictive channel reservation techniques have widely been studied in mobile cellular networks in order to meet the desired quality-of-service requirements. Those efforts are mostly concentrated on predicting the target cell that a mobile will move to and reserving the channel before the actual handoff, and subsequently reducing handoff-dropping probability and improving bandwidth utilization. In this paper, we propose adaptive reporting schemes that a mobile reports its mobility status information such as position, speed, and direction in an appropriate moment based on the user's mobility pattern characteristics and, hence the network can make a more-accurate prediction on the user's mobility. We show from the simulations that the proposed scheme is capable of keeping target cell prediction more accurate and required number of reporting through the wireless up-link channel lower.