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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
Power Allocation Strategy for Soft-Decision-and-Forward Cooperative Communication System
Song, Kyoung-Young ; Kim, Jae-Hong ; No, Jong-Seon ; Chung, Ha-Bong ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 1C, 2010, Pages 1~7
In this paper, the performance of the soft-decision-and-forward (SDF) protocol in the cooperative communication network with one source, one relay, and one destination, where each node has two transmit and receive antennas, is analyzed in terms of the bit error rate (BER) obtained from the pairwise error probability (PEP). For the slow-varying Rayleigh fading channel, the optimal and suboptimal power allocation ratios are determined without feedback. The optimal power allocation can be obtained by minimizing the average PEP. For the tractability, an alternative strategy of maximizing the product SNR of direct and relay links, which we call the suboptimal power allocation, is considered. Through the numerical analysis, we show that the performance gap between the suboptimal and the optimal power allocation is negligible in the high SNR region.
Small Target Detection Using Cross Product Based on Temporal Profile in Infrared Image Sequences
Kim, Byoung-Ik ; Bea, Tea-Wuk ; Kim, Young-Choon ; Ahn, Sang-Ho ; Kim, Duk-Gyoo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 1C, 2010, Pages 8~16
This paper presents a new small target detection method using the cross product of the temporal pixels based on the temporal profile in infrared (IR) image sequences. The temporal characteristics of small targets and the various backgrounds are different. A new algorithm classifies target pixels and the background pixels through the hypothesis testing using the cross product of pixels on the temporal profile and predicts the temporal backgrounds based on the results. The small targets are detected by subtracting the predicted temporal background profile from the original temporal profile. For the performance comparison between the proposed algorithm and the conventional algorithms, the receiver operating characteristics (ROC) curves is computed in experiment. Experimental results show that the proposed algorithm has better discrimination and a lower false alarm rate than the conventional methods.
An Adaptive Noise Removal Method Using Local Statistics and Generalized Gaussian Filter
Song, Won-Seon ; Nguyen, Tuan-Anh ; Hong, Min-Cheol ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 1C, 2010, Pages 17~23
In this paper, we present an adaptive noise removal method using local statistics and generalized Gaussian filter. we propose a generalized Gaussian filter for removing noise effectively and detecting noise adaptively using local statistics based human visual system. The simulation results show the objective and subjective capabilities of the proposed algorithm.
A Study on Object Detection Algorithm for Abandoned and Removed Objects for Real-time Intelligent Surveillance System
Jeon, Ji-Hye ; Park, Jong-Hwa ; Jeong, Cheol-Jun ; Kang, In-Goo ; An, Tae-Ki ; Park, Goo-Man ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 1C, 2010, Pages 24~32
In this paper we proposed an object tracking system that detects the abandoned and removed objects, which is to be used in the intelligent surveillance applications. After the GMM based background subtraction and by using histogram method, the static region is identified to detect abandoned and removed objects. Since the system is implemented on DSP chip, it operates in realtime and is programmable. The input videos used in the experiment contain various indoor and outdoor scenes, and they are categorized into three different complexities; low, midium and high. By 10 times of experiment, we obtained high detection ratio at low and medium complexity sequences. On the high complexity video, successful detection ratio was relatively low because the scene contains crowdedness and repeated occlusion. In the future work, these complicated situation should be solved.
Blind Equalization based on Maximum Cross-Correntropy Criterion using a Set of Randomly Generated Symbol
Kim, Nam-Yong ; Kang, Sung-Jin ; Hong, Dae-Ki ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 1C, 2010, Pages 33~39
Correntropy is a generalized correlation function that contains higher order moments of the probability density function (PDF) than the conventional moment expansions. The criterion maximizing cross-correntropy (MCC) of two different random variables has yielded superior performance particularly in nonlinear, non-Gaussian signal processing comparing to mean squared error criterion. In this paper we propose a new blind equalization algorithm based on cross-correntropy criterion which uses, as two variables, equalizer output PDF and Parzen PDF estimate of a set of randomly generated symbols that complies with the transmitted symbol PDF. The performance of the proposed algorithm based on MCC is compared with the Euclidian distance minimization.
The Optimization of Timing Recovery Loop for an MQASK All Digital Receivers
Seo, Kwang-Nam ; Kim, Chong-Hoon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 1C, 2010, Pages 40~44
The timing error detector(TED) employed in the closed loop type timing synchronization scheme for an MQASK all digital receiver suffers from the selfnoise-induced timing jitter. To eliminate the timing jitter a prefilter can be added in front of the TED. The prefilter method, however, degrades the stability and timing acquisition performance due to the loop delay and increases the complexity of the synchronizer. This paper proposes a polyphase filter type resampler approach to optimize the performance and architecture of the synchronizer simultaneously. The proposed scheme uses two resamplers which performs matched filtering and matched prefiltering so that the loop delay is minimized with minimal hardware resources. Simulation results showed an excellent acquisition performance with reduced timing jitter.
Triangulation Algorithm for Multi-user Spatial Multiplexing in MIMO Downlink Channels
Lee, Heun-Chul ; Paulraj, Aroyaswami ; Lee, In-Kyu ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 1C, 2010, Pages 45~54
This paper studies the design of a multiuser multiple-input multiple-output (MIMO) system, where a base station (BS) transmits independent messages to multiple users. The remarkable "dirty paper coding (DPC)" result was first presented by Costa that the capacity does not change if the Gaussian interference is known at the transmitter noncausally. While several implementable DPC schemes have been proposed recently for single-user dirty-paper channels, DPC is still difficult to implement directly in practical multiuser MIMO channels. In this paper, we propose a network channel matrix triangulation (NMT) algorithm for utilizing interference known at the transmitter. The NMT algorithm decomposes a multiuser MIMO channel into a set of parallel, single-input single-output dirty-paper subchannels and then successively employs the DPC to each subchannel. This approach allows us to extend practical single-user DPC techniques to multiuser MIMO downlink cases. We present the sum rate analysis for the proposed scheme. Simulation results show that the proposed schemes approach the sum rate capacity of the multiuser MIMO downlink at moderate signal-to-noise ratio (SNR) values.
Baseband Signal Compensation Scheme for Frequency Selective Fading Channel and RF Impairments in OFDM System
Kim, Jae-Kil ; Kim, Jeong-Been ; Hwang, Jin-Yong ; Shin, Dong-Chul ; Ahn, Jae-Min ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 1C, 2010, Pages 55~64
In this paper, we propose a new compensation scheme for combined channel distortions and RF impairments based on the analysis of the impacts of IQ(In-phase/Quadrature) imbalance and phase noise on the OFDM(Orthogonal Frequency Division Multiplexing) system in the direct conversion transceiver and frequency selective fading channel distortion. The proposed scheme estimates the combined distortion by the use of training symbols and the residual distortion by pilot symbols and compensates the combined distortion, including IQ imbalance, phase noise and multipath fading at the same time. The simulation results show that the proposed scheme compensates the combined distortion of IQ imbalance, phase noise and multipath fading simultaneously.
Compensation for Nonlinear Distortion in OFDM Systems Using a Digital Predistorter Based on the Canonical PWL Model
Seo, Man-Jung ; Shim, Hee-Sung ; Im, Sung-Bin ; Jung, Jae-Ho ; Lee, Kwang-Chun ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 1C, 2010, Pages 65~76
Orthogonal frequency division multiplexing (OFDM) is an attractive technique for achieving high-bit-rate wireless data transmission. However, multicarrier systems such as OFDM show great sensitivity to nonlinear distortion. The OFDM structure requires a summation of a large number of subcarriers for multicarrier modulation, and as a result of this summation large signal envelope fluctuations occur. These fluctuations make OFDM systems to be very sensitive to nonlinear distortion introduced by the high power amplifier (HPA) at the transmitter. In this paper, we propose a canonical piecewise-linear (CPWL) model based digital predistorter to compensate for nonlinear distortion introduced by the high peak-to-average power ratio (PAPR) and the HPA in OFDM systems. The performance of the new predistortion scheme for OFDM systems is evaluated in terms of total degradation (TD) and bit error rate (BER). The simulation results demonstrated that the proposed predistorter achieves significant performance improvement by effectively compensating for the nonlinear distortion introduced by the HPA.
Analysis of Ranging Performance According to Analog Front End Characteristics in a Noncoherent UWB System
Kim, Jae-Woon ; Park, Young-Jin ; Lee, Soon-Woo ; Shin, Yo-An ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 1C, 2010, Pages 77~86
In this paper, we present a noncoherent IR-UWB (Impulse Radio-Ultra Wide Band) ranging system with an AFE (Analog Front End) composed of a simple integrator and an 1-bit ADC (Analog-to-Digital Converter), and define AFE characteristics affecting the ranging performance. This system is realistic and easy to implement, since the integrator simply accumulates signal energies and the simple 1-bit ADC is applied instead of the multi-bit ADCs for coherent IR-UWB systems. On the other hand, its ranging accuracy is largely affected channel environments such as noise, multipath fading and so on, since the noncoherent receiver simply squares and integrates the received signals. However, despite these practical importances, there are few conventional researches on the performance analysis according to AFE characteristics in IR-UWB ranging systems. To this end, we analyze in this paper ranging performance according to AFE characteristics for the noncoherent IR-UWB ranging system in various wireless channel environments, and through these results we also present system parameters to be considered in UWB hardware designs.
An Improved TDoA Localization with Particle Swarm Optimization in UWB Systems
Le, Tan N. ; Kim, Jae-Woon ; Shin, Yo-An ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 1C, 2010, Pages 87~95
In this paper, we propose an improved TDoA (Time Difference of Arrival) localization scheme using PSO (Particle Swarm Optimization) in UWB (Ultra Wide Band) systems. The proposed scheme is composed of two steps: re-estimation of TDoA parameters and re-localization of a tag position. In both steps, the PSO algorithm is employed to improve the performance. In the first step, the proposed scheme re-estimates the TDoA parameters obtained by traditional TDoA localization to reduce the TDoA estimation error. In the second step, the proposed scheme with the TDoA parameters estimated in the first step, re-localizes the tag to minimize the location error. The simulation results show that the proposed scheme achieves a more superior location performance to the traditional TDoA localization in both LoS (Line-of-Sight) and NLoS (Non-Line-of-Sight) channel environments.
A Feedback and Noise Cancellation Algorithm of Hearing Aids Using Adaptive Beamforming Method
Lee, Haeng-Woo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 1C, 2010, Pages 96~102
This paper proposes a new adaptive algorithm to cancel the acoustic feedback and noise signals in the digital hearing aids. The proposed algorithm improves its convergence performances by canceling the speech signal from the residual signal using two microphones. The feedback canceller firstly cancels the feedback signal among the mic signal, and then it is reduced the noise using the beamforming method. To verify the performances of the proposed algorithm, the simulations were carried out for some cases. As the results of simulations, it was proved that the feedback canceller and the noise canceller advance about 14.43 dB for SFR, 10.19 dB for SNR respectively during speech, in the case of using the new algorithm.
An Enhanced Frequency Synchronization Algorithm for 3GPP LTE FDD/TDD Dual Mode Downlink Receiver
Shim, Myung-Jun ; Jang, Jun-Hee ; Choi, Hyung-Jin ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 1C, 2010, Pages 103~112
In this paper, we propose a coarse and fine frequency synchronization method which is suitable for the 3GPP(3rd Generation Partnership Project) LTE(Long Term Evolution) FDD(Frequency Division Duplexing) / TDD(Time Division Duplexing) dual mode system. In general, PSS(Primary Synchronization Signal) correlation based estimation method and CP(Cyclic Prefix) correlation based tracking loop are applied for coarse and fine frequency synchronization in 3GPP LTE OFDMA(Orthogonal Frequency Division Multiple Access) system, respectively. However, the conventional coarse frequency synchronization method has performance degradation caused by fading channel and squaring loss. Also, the conventional fine frequency synchronization method cannot guarantee stable operation in TDD mode because of signal power difference between uplink and downlink subframe. Therefore, in this paper, we propose enhanced coarse and fine frequency synchronization methods which can estimate more accurately in multi-path fading channel and high speed channel environments and has stable operation for TDD frame structure, respectively. By computer simulation, we show that the proposed methods outperform the conventional methods, and verify that the proposed frequency synchronization method can guarantee stable operation in 3GPP LTE FDD/TDD dual mode downlink receiver.
A CP Detection Based SSS Detection Method for Initial Cell Search in 3GPP LTE FDD/TDD Dual Mode Downlink Receiver
Kim, Jung-In ; Jang, Jun-Hee ; Choi, Hyung-Jin ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 1C, 2010, Pages 113~122
In this paper, we propose a CP (Cyclic Prefix) detection based SSS (Secondary Synchronization Signal) detection method for initial cell search in 3GPP LTE (3rd Generation Partnership Project Long Term Evolution) FDD/TDD (Frequency Division Duplex/Time Division Duplex) dual mode downlink receiver. In general, a blind coherent SSS detection method which can detect SSS without CP detection is applied. However, coherent detection method caused performance degradation by channel compensation error at high speed environment because it uses estimated CFR (Channel Frequency Response) at PSS (Primary Synchronization Signal), and it can be more serious problem in TDD mode due to increased distance between PSS and SSS. Also blind detectionhas the drawback of high computational complexity. Therefore, we proposed a CP type pre-decision structure with non-coherent SSS detection which has stable operation in high speed channel environments for 3GPP LTE TDD mode as well as FDD mode, and can reduce computational complexity by applying CP detection before SSS detection. Simulation results show that the proposed method has stable operation for 3GPP LTE TDD/FDD dual mode downlink receiver in various channel environments.
An Analysis of Code Tracking Bias for Civilian Signals in GNSS
Yoo, Seung-Soo ; Kim, Yeong-Moon ; Kim, Jun-Tae ; Kim, Sun-Yong ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 1C, 2010, Pages 123~129
In this paper, we analyze the code tracking biases of single and double early-minus-late processing schemes which are widely used code tracking method for global navigation satellite systems. The code tracking bias which results from the distortion in symmetry of correlation values is arisen in the presence of multipath signals. To analyze them, two civil signals which are spreading signals modulated by binary phase shift keying and binary offset carrier are considered.
A Design for Uplink Indoor Acoustic Positioning System based on Time-Difference-of-Arrival of Self-Generating Sounds
Yoo, Seung-Soo ; Kim, Yeong-Moon ; Lee, Ki-Seung ; Yoon, Kyoung-Ro ; Lee, Seok-Pil ; Kim, Sun-Yong ;
The Journal of Korean Institute of Communications and Information Sciences, volume 35, issue 1C, 2010, Pages 130~137
An uplink indoor positioning system is proposed in the present work, where the acoustic signals are solely used for positioning. The underlying acoustic signals include whistle, finger snap, and hands-clapping. In the proposed method, positioning is achieved by finding the time-difference-of-arrivals using several self-generating sounds. To evaluate the feasibility of the signals and their positioning accuracies, the database of 100 persons about self-generating acoustic signals is built up. The results show that the hands-clapping sound is the most suitable for acoustic-based indoor positioning.