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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 34, Issue 12C - Dec 2009
Volume 34, Issue 12B - Dec 2009
Volume 34, Issue 12A - Dec 2009
Volume 34, Issue 11C - Nov 2009
Volume 34, Issue 11B - Nov 2009
Volume 34, Issue 11A - Nov 2009
Volume 34, Issue 10C - Oct 2009
Volume 34, Issue 10B - Oct 2009
Volume 34, Issue 10A - Oct 2009
Volume 34, Issue 9C - Sep 2009
Volume 34, Issue 9B - Sep 2009
Volume 34, Issue 9A - Sep 2009
Volume 34, Issue 8C - Aug 2009
Volume 34, Issue 8B - Aug 2009
Volume 34, Issue 8A - Aug 2009
Volume 34, Issue 7C - Jul 2009
Volume 34, Issue 7B - Jul 2009
Volume 34, Issue 7A - Jul 2009
Volume 34, Issue 6C - Jun 2009
Volume 34, Issue 6B - Jun 2009
Volume 34, Issue 6A - Jun 2009
Volume 34, Issue 5C - May 2009
Volume 34, Issue 5B - May 2009
Volume 34, Issue 5A - May 2009
Volume 34, Issue 4C - Apr 2009
Volume 34, Issue 4B - Apr 2009
Volume 34, Issue 4A - Apr 2009
Volume 34, Issue 3C - Mar 2009
Volume 34, Issue 3B - Mar 2009
Volume 34, Issue 3A - Mar 2009
Volume 34, Issue 2C - Feb 2009
Volume 34, Issue 2B - Feb 2009
Volume 34, Issue 2A - Feb 2009
Volume 34, Issue 1C - Jan 2009
Volume 34, Issue 1B - Jan 2009
Volume 34, Issue 1A - Jan 2009
Selecting the target year
An Optimal Orthogonal Overlay for Fixed MIMO Wireless Link
Yun, Yeo-Hun ; Cho, Joon-Ho ;
The Journal of Korean Institute of Communications and Information Sciences, volume 34, issue 10C, 2009, Pages 929~936
In this paper, we consider designing a multi-input multi-output (MIMO) overlay system for fixed MIMO wireless link, where a frequency flat narrowband channel is shared by multiple transmitter and receiver pairs. Assuming the perfect knowledge of the second-order statistics of the received legacy signals and the composite channels from the overlay transmitter to the legacy receivers, the jointly optimal linear precoder and decoder matrices of the MIMO overlay system is derived to minimize the total mean squared error (MSE) of the data symbol vector, subject to total average transmission power and zero interference induced to legacy MIMO systems already existing in the frequency band of interest. Furthermore, the necessary and sufficient condition for the existence of the optimal solution is also derived.
On the Absorbing Sets of the Regular LDPC Codes with Variable Node Degree Three
Lee, Ki-Jun ; Chung, Ha-Bong ; Jang, Hwan-Seok ;
The Journal of Korean Institute of Communications and Information Sciences, volume 34, issue 10C, 2009, Pages 937~945
In this paper, we investigate into the existence and various properties of absorbing sets in regular LDPC codes with variable node degree three. Also, we figure out the critical number of some absorbing sets that are believed to be the major cause of error floor in (3,5) Tanner LDPC codes.
A Design of RFID Mutual Authentication System based on Open Channel
Yoon, Eun-Jun ; Yoo, Kee-Young ;
The Journal of Korean Institute of Communications and Information Sciences, volume 34, issue 10C, 2009, Pages 946~954
General RFID system has assumed that the communication channel between reader and back-end database is secure channel. However, the reader can be communicated with the database through insecure channel like the communication channel between the reader and the tag according to application environment. In this paper, we propose a new secure RFID mutual authentication protocol based on open network channel which assumed that all communication channels between the database, the reader and the tag are insecure communication channels. The proposed protocol uses a secure one-way hash function to provide authentication and integrity against all communication messages which exchanged on the open channels. In addition, we designed that the proposed protocol can provide forward secrecy by performing the database and the tag update their old secret key with a new secret key after finished mutual authentication.
Residual Echo Suppression Based on Tracking Echo-Presence Uncertainty
Park, Yun-Sik ; Chang, Joon-Hyuk ;
The Journal of Korean Institute of Communications and Information Sciences, volume 34, issue 10C, 2009, Pages 955~960
In this paper, we propose a novel approach to residual echo suppression (RES) algorithm based on tracking echo-presence uncertainty (TEPU) to improve the performance of acoustic echo suppression (AES) in the frequency domain. In the proposed method, the ratio of the microphone input and the echo-suppressed output signal power is employed as the threshold value for the decision rule to estimate the echo-presence uncertainty applied to the RES filter. The proposed RES scheme estimates the echo presence uncertainty in each frequency bin and effectively reduces residual echo signal in a simple fashion. The performance of the proposed algorithm is evaluated by the objective test and yields better results compared with the conventional schemes.
Method of Lossless Image Compression Using Hybrid Bitplane Coding
Moon, Young-Ho ; Choi, Jong-Bum ; Sim, Woo-Sung ;
The Journal of Korean Institute of Communications and Information Sciences, volume 34, issue 10C, 2009, Pages 961~967
In this paper, the lossless compression method is proposed for an 8-bit bitplane of the input image. The lower bitplanes are not well compressed because of irregularity of pixels. To overcome these drawbacks, this paper propose a mixed coding method that using the block-based lossless compression and the bit-based losselss compression, introducing the H. 264 and the JBIG. First, to take advantage of the characteristics of the bitplanes, 8-bitplane against the top 4 bits and lower 4 bits were separated. Next, the JBIG compression method was used in separated top 4-bitplane because of a lot of correlation between bits. And a separated lower 4-bitplane was applied the improved method that using the H. 264 lossless prediction. A pre-processing method applied to the lower 4-bitplane then irregular distribution of pixel values are converted to regular. Using the proposed method to test for various test images were performed. Experimental results from a printer using 8-bit image compared to JBIG average 19%, lower 4bit image compression performance with an average of 11% could be obtained.
A Skipping Method of Transformation and Quantization Process for Fast H.264 Encoder
Song, Won-Seon ; Hong, Min-Cheol ;
The Journal of Korean Institute of Communications and Information Sciences, volume 34, issue 10C, 2009, Pages 968~974
In this paper, we present a skipping method of transformation and quantization process using skip blocks estimation in fast H.264 video encoder. In order to reduce the complexity, we estimate skip mode blocks using integer discrete cosine transform and quantization and a skipping condition is derived by the analysis of those processes. The experimental result show that the proposed algorithm has effective estimations.
A Mixing of H.264/AVC Video Streams Based on Slice in The Compressed Domain
Jang, Seung-Min ; Yu, Hong-Yeon ; Kim, Sang-Kyune ; Park, Il-Kyun ; Hong, Sung-Hoon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 34, issue 10C, 2009, Pages 975~982
In this paper, we propose a novel mixing algorithm for multiple video streams, which can guarantee low complexity and low end-to-end delay. In the propose algorithm, we change the syntax bitstream in the compressed domain. And we mix the H.264/AVC video streams by coded slice unit. The syntax bitstream for a mixing changes according to the arrangement of videos streams in which it organizes the mixing screen layout. Experimental results show more than 4 video streams could be mixed at high speed. Moreover, it could display in the player which it supports the standard H.264/AVC without the picture quality loss.
Real-time Optimization of H.264 Software Encoder on Embedded DSP System
Roh, Si-Bong ; Ahn, Hee-June ; Lee, Myeong-Jin ; Oh, Hyuk-Jun ;
The Journal of Korean Institute of Communications and Information Sciences, volume 34, issue 10C, 2009, Pages 983~991
While H.264/AVC is in wide use for multimedia applications such as DMB and IPTV service, we have limited usage cases for embedded real-time applications due to its high computational demand. The paper provides judicious guide line for optimization method selection, by presenting the detailed experiments data through the development process of a real time H.264 software encoder on embedded DSP. The experimental analysis includes an intensive profiling analysis, fast algorithm application, optimal memory assignment, and intrinsic-based instruction selection. We have realized a real-time software that encodes CIF resolution videos 15 fps on TMS320DM64x processors.
Multi-band CIC Filter based Low Complexity Spectrum Sensing Method
Lee, Su-Bok ; Choi, Joo-Pyoung ; Lee, Won-Cheol ;
The Journal of Korean Institute of Communications and Information Sciences, volume 34, issue 10C, 2009, Pages 992~1000
Available electric wave resources have been limited than frequency demands that increase with the development of radio communication. According to FCC's (Federal Communication Commission) report, 70% of allocated spectrum was unused. This means that the lack phenomenon of electronic wave resources is ineffectively managed compare with the finiteness of frequency resources. According to the recognition of unused frequency within allocated band, this progress has been investigating to identify the unused TV channel and provide radio communication services. This paper proposed the sensing algorithm that efficiently recognizes the frequency resources which does not use and shares with the licensed user through using the multi-band CIC (Cascaded Integrator Comb) filter based on polyphase filter bank. The simulation results verifies that the proposed scheme can obtain the similar performance of variance and relatively low complexity to the existing scheme.
Blind Frequency offset Estimation for Radio Resource Saving in OFDM
Jeon, Hyoung-Goo ; Kim, Kyoung-Soo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 34, issue 10C, 2009, Pages 1001~1009
In this paper, an efficient blind frequency offset estimation method for radio resource saving in orthogonal frequency division multiplexing (OFDM) systems is proposed. In the proposed method, we obtain two time different received OFDM signal blocks by using the cyclic prefix and define the cost function by using the two OFDM signal blocks. We show that the cost function can be approximately expressed as a closed form cosine function. The approximated cosine function can be obtained from three independent cost function values calculated at three different frequency offsets. In the proposed method, the frequency offset can be estimated by calculating a frequency offset minimizing the approximated cosine function without searching all the frequency offset range. Unlike the conventional methods such as MUSIC method, the accuracy of the proposed method is independent of the searching resolution since the closed form solution exists. The computer simulation shows that the performance of the proposed method is superior to those of the MUSIC and the oversampling method.
An Improved Ordering Method for MIMO Signal Detection Using QR Decomposition and Successive Interference Cancellation
Bak, Sang-Hyun ; Kim, Jae-Kwon ; Yang, Won-Young ;
The Journal of Korean Institute of Communications and Information Sciences, volume 34, issue 10C, 2009, Pages 1010~1015
In this paper, we propose a novel detection ordering technique for MIMO signal detection methods based on QR decomposition and successive interference cancellation (SIC). Recently, new signal detection methods for spatially multiplexed (SM) MIMO systems were proposed, where all the constellation points are tried as the first layer symbol, and the remaining layer symbols are estimated via SIC, producing candidate vectors. Finally, the ML metric values are calculated for the candidate vectors, that are again used to select the best symbol vector. It was also shown that the ordering method in the conventional V-BLAST is not suitable to these signal detection methods. In this paper, we propose a novel ordering method, and we show via computer simulations that the proposed ordering method improves the error performance.
Advanced Region Slopes Method to Reduce Code Tracking Bias in Future Global Navigation Satellite Systems
Yoo, Seung-Soo ; Lee, Young-Yoon ; Kim, Yeong-Moon ; Kim, Sun-Yong ;
The Journal of Korean Institute of Communications and Information Sciences, volume 34, issue 10C, 2009, Pages 1016~1023
In this paper, a tracking bias compensation method is proposed for future global navigation satellite systems (GNSSs). It is observed that the correlation function of a GNSS signal has many peaks and remains almost unchanged in the advanced offset region as a result of the multipath signals arriving at the receiver later than a line-of-sight signal. Based on these observations, we use the slopes in the advanced offset region to compensate for the code tracking bias, and obtain the maximum code tracking bias, which is essential to implement the proposed scheme, in static multipath environments. Finally, it is demonstrated that the proposed compensation method is very effective for the GNSS signal tracking in terms of the code tracking biases and their running averages.