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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
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Performance Analysis of OFDM Timing Synchronization Method with Imperfect Noise Estimation
Lee, Ki-Chang ; Yoon, Young-Joong ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 3C, 2007, Pages 189~194
This paper derives and computes the detection probability of timing synchronization in an orthogonal frequency division multiplexing (OFDM) system encountered with a multipath Rayleigh fading channel and imperfect noise estimation. The timing synchronization scheme using a simple repeated constant amplitude zero auto-correlation (CAZAC) training symbol and correlation techniques is adopted. With this provision, we focus on the numerical analysis for OFDM timing synchronization scheme employing a preadvancement technique to reduce the inter-symbol interference (ISI). For measuring system performance, the detection performance derived in the considered system is presented in a multipath Rayleigh fading channel.
CRC-Turbo Concatenated Code for Hybrid ARQ System
Kim, Woo-Tae ; Kim, Jeong-Goo ; Joo, Eon-Kyeong ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 3C, 2007, Pages 195~204
The cyclic redundancy check(CRC) code used to decide retransmission request in hybrid automatic repeat request(HRAQ) system can also be used to stop iterative decoding of turbo code if it is used as an error correcting code(ECC) of HARQ system. Thus a scheme to use CRC code for both iteration stop and repeat request in the HARQ system with turbo code based on the standard of cdma 2000 system is proposed in this paper. At first, the optimum CRC code which has the minimum length without performance degradation due to undetected errors is found. And the most appropriate turbo encoder structure is also suggested. As results, it is shown that at least 32-bit CRC code should be used and a turbo code with 3 constituent encoders is considered to be the most appropriate one.
Low Latency Algorithms for Iterative Codes
Choi, Seok-Soon ; Jung, Ji-Won ; Bae, Jong-Tae ; Kim, Min-Hyuk ; Choi, Eun-A ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 3C, 2007, Pages 205~215
This paper presents low latency and/or computation algorithms of iterative codes of turbo codes, turbo product codes and low density parity check codes for use in wireless broadband communication systems. Due to high coding complexity of iterative codes, this paper focus on lower complexity and/or latency algorithms that are easily implementable in hardware and further accelerate the decoding speed.
Optimal Bit Split Methods and Performance Analysis for Applying to Multilevel Modulation of Iterative Codes
Bae, Jong-Tae ; Jung, Ji-Won ; Choi, Seok-Soon ; Kim, Min-Hyuk ; Chang, Dae-Ig ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 3C, 2007, Pages 216~225
This paper presents bit splitting methods to apply multilevel modulation to iterative codes such as turbo code, low density parity check code and turbo product code. Log-likelihood ratio method splits multilevel symbols to bits using the received in-phase and quadrature component based on Gaussian approximation. However it is too complicate to calculate and implement hardware due to exponential and log calculation. therefore this paper presents Euclidean, MAX and Sector method to reduce the high complexity of LLR method. We propose optimal bit splitting method for three iterative codes.
New Constructions of Binary LCZ Sequence Sets With Flexible LCZ and Set Size
Kim, Young-Sik ; Jang, Ji-Woong ; No, Jong-Seon ; Chung, Ha-Bong ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 3C, 2007, Pages 226~233
In this paper, we construct new LCZ sequence sets with parameters
. In this scheme, we can relatively freely choose the LCZ length L and the resulting LCZ sequence set has the size in which is nearly optimal with respect to Tang, Fan, and Matsufuji bound.
Designing a Quantizer of LPC Parameters for the Narrowband Speech Coder using Block-Constrained Trellis Coded Quantization
Jun, Ja-Kyoung ; Park, Sang-Kuk ; Kang, Sang-Won ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 3C, 2007, Pages 234~240
In this paper, low complexity block constrained trellis coded quantization (BC-TCQ) structures are introduced, and a predictive BC TCQ encoding method is developed for quantization of line spectrum frequencies (LSF) parameters for narrowband speech coding applications. Trellis-coded quantization(TCQ) is a form of VQ that builds the VQ codebook from interleaved constituent scalar quantization codebooks. The performance is compared to the other VQ, demonstrating reduction in spectral distortion and significant reduction in encoding complexity. The predictive BC-TCQ is about 0.47107 dB superior to the IS-641 split-VQ, 26bits/frame, in spectral distortion sense. The BC-TCQ is 64.54%, 76.93%, 2.35% of the IS-641 split-VQ, respectively, in the complexity of the additions, multiplies, comparisons.
Low Complexity Hybrid Interpolation Algorithm using Weighted Edge Detector
Kwon, Hyeok-Jin ; Jeon, Gwang-Gil ; Jeong, Je-Chang ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 3C, 2007, Pages 241~248
In predictive image coding, a LS (Least Squares)-based adaptive predictor is an efficient method to improve image edge predictions. This paper proposes a hybrid interpolation with weighted edge detector. A hybrid approach of switching between bilinear interpolation and EDI (Edge-Directed Interpolation) is proposed in order to reduce the overall computational complexity The objective and subjective quality is also similar to the bilinear interpolation and EDI. Experimental results demonstrate that this hybrid interpolation method that utilizes a weighted edge detector can achieve reduction in complexity with minimal degradation in the interpolation results.
A New Coeff-Token Decoding Method based on the Reconstructed Variable Length Code Table
Moon, Yong-Ho ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 3C, 2007, Pages 249~255
In general, a large amount of the memory accesses are required for the CAVLC decoding in H.264/AVC. It is a serious problem for the applications such as a DMB and videophone services because the considerable power is consumed for accessing the memory. In order to solve this problem, we propose an efficient decoding method for the coeff-token which is one of the syntax elements of CAVLC. In this paper, the variable length code table is re-designed with the new codewords which are defined by investigating the architecture of the conventional codeword for the coeff_token element. A new coeff_token decoding method is developed based on the suggested table. The simulation results show that the proposed algorithm achieves an approximately 85% memory access saving without video-quality degradation, compared to the conventional CAVLC decoding.
A Blind Watermarking for 3-D Mesh Sequence Using Temporal Wavelet Transform of Vertex Norms
Kim, Min-Su ; Cho, Jae-Won ; Prost, Remy ; Jung, Ho-Youl ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 3C, 2007, Pages 256~268
In this paper, we present a watermarking method for 3-D mesh sequences. The main idea is to transform vertex norm with the identical connectivity index along temporal axis using wavelet transform and modify the distribution of wavelet coefficients in temporally high (or middle) frequency frames according to watermark bit to be embedded. All vertices are divided into groups, namely bin, using the distribution of coefficients in low frequency frames. As the vertices with the identical connectivity index over whole frames belong to one bin, their wavelet coefficients are also assigned into the same bin. Then, the watermark is embedded into the wavelet coefficients of vertex norm. Due to the use of the distribution, our method can retrieve the hidden watermark without any information about original mesh sequences in the process of watermark detection. Through simulations, we show that the proposed is flirty robust against various attacks that are probably concerned in copyright protection of 3-D mesh sequences.
Fast Mode Decision for MPEG-2 to H.264 Transcoding
Kim, Won-Kyun ; Park, Kyung-Jun ; You, Jong-Min ; Jeong, Je-Chang ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 3C, 2007, Pages 269~277
In this paper, we present a efficient transcoding method from MPEG-2 to H.264. The proposed transcoder is the transcoding method for spatial domain which consists of MPEG-2 decoder part and H.264 encoding part. In transcoder, we can get useful information to estimate less probable modes from MPEG-2 decoder. Using this information, H.264 encoder chooses the macroblock mode of I-frame and P-frame adaptively to reduce the whole complexity of the transcoder. Our experimental result shows that the proposed algorithm can archive about
computational saving without significant degradation of visual quality and increasing of bit rate.
Fine Directional De-interlacing Algorithm
Park, Sang-Jun ; Jin, Soon-Jong ; Jeong, Je-Chang ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 3C, 2007, Pages 278~286
In this paper, an efficient algorithm is proposed for the interpolation of interlaced images. First of all, by efficiently estimating the directional spatial correlations of neighboring pixels, increased interpolation accuracy can be achieved. And then using the gradient vector which was obtained by Sobel operation, enables to consider the fine directional edges and make it possible to estimate the accurate direction of edges. In other words, it is possible to interpolate the interlaced images with considering the characteristics of images. In addition, by altering the conventional edge detector for the purpose of a easy De-interlacing and multiplying the optimal translation coefficients to each of the gradient vectors, an efficient interpolation for images can be achieved. Comparing with the conventional De-interlacing algorithms, proposed algorithm not only reduced the complexity but also estimated the accurate edge direction and the proposed scheme have been clearly verified that it enhances the objective and subjective image quality by the extensive simulations for various images.
3D Animation Watermarking Using Position Interpolator
Bae, Sung-Ho ; Lee, Suk-Hwan ; Kim, Jung-Hyun ; Kwon, Ki-Ryong ; Lee, Eung-Joo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 3C, 2007, Pages 287~296
3D keyframe animation is used widely in 3D graphics for real-time animation. This is a method that registers the animated key values in the important several frames among the entire frames and generates the rest frame by interpolator using the registered key values. This paper proposed the watermarking for 3D keyframe animation using PositionInterpolator. The proposed algorithm selects randomly the embedding meshes, which are transform nodes among the entire hierarchical structure. Then the watermark is embedded into keyValues of PositionInterpolator in selected transform node. Experimental results verified that the proposed algorithm has the robustness against geometrical attacks and timeline attacks.
FPGA Design of Motion JPEG2000 Encoder for Digital Cinema
Seo, Young-Ho ; Choi, Hyun-Jun ; Kim, Dong-Wook ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 3C, 2007, Pages 297~305
In the paper, a Motion JPEG2000 coder which has been set as the standard for image compression by the Digital Cinema Initiatives (DCI), an organization composed of major movie studios was implemented into a target FPGA. The DWT (Discrete Wavelet Transform) based on lifting and the Tier 1 of EBCOT (Embedded Block Coding with Optimized Truncation) which are major functional modules of the JPEG2000 were setup with dedicated hardware. The Tier 2 process was implemented in software. For digital cinema the tile-size was set to support
pixels. To ensure the real-time operations, three entropy encoders were used. When Verilog-HDL was used for hardware, resources of 32,470 LEs in Altera's Stratix EP1S80 were used, and the hardware worked stably at the frequency of 150Mhz.
FPGA Design of Turbo Code based on MAP
Seo, Young-Ho ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 3C, 2007, Pages 306~313
In this paper, we efficiently implemented turbo code algorithm in FPGA H/W(hardware) resource. The used turbo code algorithm has the characteristics; the size of constraint is 3, encoder type is 1/3, the size of random interleaver is 2048. The proposed H/W consists of MAP block for calculating alpha and delta using delta value, storing buffer for each value, multiplier for calculating lamda, and lamda buffer. The proposed algorithm and H/W architecture was verified by C++ language and was designed by VHDL. Finally the designed H/W was programmed into FPGA and tested in wireless communication environment for field availability. The target FPGA of the implemented H/W is VERTEX4 XC4VFX12-12-SF363 and it is stably operated in 131.533MHz clock frequency (7.603ns).
GBNSGA Optimization Algorithm for Multi-mode Cognitive Radio Communication Systems
Park, Jun-Su ; Park, Soon-Kyu ; Kim, Jin-Up ; Kim, Hyung-Jung ; Lee, Won-Cheol ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 3C, 2007, Pages 314~322
This paper proposes a new optimization algorithm named by GBNSGA(Goal-Pareto Based Non-dominated Sorting Genetic Algorithm) which determines the best configuration for CR(Cognitive Radio) communication systems. Conventionally, in order to select the proper radio configuration, genetic algorithm has been introduced so as to alleviate computational burden along the execution of the cognition cycle proposed by Mitola. This paper proposes a novel optimization algorithm designated as GBNSGA for cognitive engine which can be described as a hybrid algorithm combining well-known Pareto-based NSGA(Non-dominated Sorting Genetic Algorithm) as well as GP(Goal Programming). By conducting computer simulations, it will be verified that the proposed method not only satisfies the user's service requirements in the form of goals. It reveals the fast optimization capability and more various solutions rather than conventional NSGA or weighted-sum approach.
Performance of a Rectangular Smart Antenna in CDMA Basestation
Hong, Young-Jin ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 3C, 2007, Pages 323~330
Performance indicators such as output SNR, SIR, SINR for rectangular smart antennas in CDMA basestations have been derived. Simulations have been carried out to find the rectangular smart antenna performance while varying the input SNR, number of antenna elements, and the interferers' spatial distributions. Simplified Conjugate Gradient Method was chosen as the underlying beam forming algorithm. It has been shown that the performance of a rectangular smart antenna is similar to that of the linear one having the same number of elements when the interferers are randomly distributed over the whole azimuth angle range.
Walsh Coded Training Signal Aided Time Domain Channel Estimation Scheme In MIMO-OFDM Systems
Jeon, Hyoung-Goo ; Jang, Jong-Wook ; Song, Hyoung-Kyu ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 3C, 2007, Pages 331~337
In this paper, we propose a novel Walsh coded training signal design and Walsh decoding method to estimate the channel response in MIMO-OFDM systems. The Walsh coded training signals are designed to have orthogonal property in time domain. Using the orthogonal property, the Walsh decoding process makes it possible to separate the desired training signal from the received signal and to estimate the channel response. The computer simulation results show that the proposed method exhibits almost the same performance as Li's original method using the optimal training sequence, even though the proposed method has much lower complexity.
A Weighted Block Adaptive Estimation for STBC Single-Carrier System in Frequency-Selective Time-Varying Channels
Baek, Jong-Seob ; Kwon, Hyuk-Jae ; Seo, Jong-Soo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 3C, 2007, Pages 338~347
In this paper, a weighted block adaptive channel estimation (WBA-CE) for a space-time block-coded (STBC) single-carrier transmission with a cyclic-prefix is proposed. In operation of the WBA-CE, a STBC matrix-wise block for filter input symbols is first formulated. Applying a weighted a posteriori error vector-based least-square (LS) criterion for this block, the coefficient correction terms of the WBA-CE are then computed. An approximate steady-state excess mean-square error (EMSE) of the WBA-CE for the stationary optimal coefficient is also analyzed. Simulation results show in a time-varying typical urban (TU) channel that the proposed channel estimator provides better bit-error-rate (BER) performances than conventional algorithms such as the NLMS and RLS channel estimators.
RFID Mutual Authentication Protocol Against Reflection Attack
Kim, Bae-Hyun ; Ryoo, In-Tae ;
The Journal of Korean Institute of Communications and Information Sciences, volume 32, issue 3C, 2007, Pages 348~354
RFID system is emerging new technology for ubiquitous computing environment. RFID system, however, provides privacy problems while the technology offers incredible rich opportunities for applications in the filed of logistics, distribution, and medical services, etc. Many researches have been conducted in order to solve this problem, but the current RFID authentication protocols are still insufficient for settling the privacy problem in the point of view of privacy intrusion and system efficiency. The purpose of this paper is to present a RFID mutual authentication protocol which improves safety level, compared with current authentication protocols. The proposed authentication protocol can provide mutual authentication services, and is secure against location tracing, spoofing, reflection attack.