• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.6C
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• pp.570-579
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• 2003

The performance of turbo codes is investigated in the direct detection optical PPM channel. We assume that an ideal photon counter is used as an optical detector and that the channel has background noise as well as quantum noise. Resulting channel model is M-ary PPM Poisson channel. We propose the structure of the transmitter and receiver for applying turbo codes to this channel. We also derive turbo decoding algorithm for the proposed coding system, by modifying the calculation of the branch metric inherent in the original turbo decoding algorithm developed for the AWGN channel. Analytical bounds are derived and computer simulation is performed to analyze the performance of the proposed coding scheme, and the results are compared with the performances of Reed-Solomon codes and convolutional codes.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.6
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• pp.119-125
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• 2005

We propose a new code-based publick key encryption scheme. It is obtained by modifying the Augot and Finiasz scheme proposed at Eurocrypt 2003. We replace the Reed-Solomon codes with general algebraic-geometry codes and employ Guruswami-Sudan decoding algorithm for decryption. The scheme is secure against Colon's attack or Kiayias and Yung's attack to which the Augot and Finiasz scheme is vulnerable. Considering basic attacks aprlied to the Augot and Finiasz scheme, we claim that the proposed scheme provides similar security levels as the Augot and Finiasz scheme was claimed to provide for given key lengths.

• Journal of Industrial Technology
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• v.25 no.B
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• pp.171-174
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• 2005

In this paper, we propose a new data encoding algorithm for a two-dimensional bar code system. In general, the one-dimensional bar code is just a key which can access detailed information to the host computer database. But the two-dimensional bar code is a new technology which can obtain high density information without access to the host computer database. We implemented the encoding algorithm for Data Matrix bar code which is the most widely used among the many kinds of two-dimensional bar codes in the field of marking using Digital Signal Processor (TMS320C31). The performance of the proposed algorithm is verified by comparing the imprinted symbols on the steel surfaces with the codes which are decoded by a bar code reader.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.5
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• pp.1035-1040
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• 2009

We propose a new encoder/decoders based on an tune able wavelength converter(TWC) and an arrayed waveguide grating(AWG) router for large capacity optical CDMA networks. The proposed encoder/decoder treats codewords of wavelength/time 2-D code simultaneously using the dynamic code allocation property of the TWC and the cyclic property of the AWG router, and multiple subscribers can share the encoder/decoder in networks. Feasibility of the structure of the proposed encoder/decoder for dynamic code allocation is tested through simulations using two wavelength/time 2-D codes, which are the generalized multi-wavelength prime code(GMWPC) and the generalized multi-wavelength Reed-Solomon code(GMWRSC). Test results show that the proposed encoder/decoder can increase the channel efficiency not only by increasing the number of simultaneous users without any multiple-access interference but by using a relatively short length CDMA codes.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.882-885
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• 2010

In view of the severe energy constraint in sensor networks, it is important to use the error control scheme of the energy efficiently. In this paper, we presented FEC (Forward Error Correcting) codes in terms of their power consumption. One method of FEC is RS (Reed-Solomon) coding, which uses block codes. RS codes work by adding extra redundancy to the data. The encoded data can be stored or transmitted. It could have errors introduced, when the encoded data is recovered. The added redundancy allows a decoder to detect which parts of the received data is corrupted, and corrects them. The number of errors which are able to be corrected by RS code can determine by added redundancy. We could predict the lifetime of RS codes which transmitted at 32 byte a 1 minutes. RS(15, 13), RS(31, 27), RS(63, 57), RS(127,115), and RS(255,239) can keep the days of 138, 132, 126, 111, and 103 respectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.7C
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• pp.659-664
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• 2006

We propose two error correcting algorithms for high-density optical storage systems. The first algorithm reduces the false-erasure declaration by reducing the sensitivity on random errors and increases the code rate using a simple erasure indication method. The second one exploits just the known indicator flag instead of error correcting code such as Reed-Solomon(RS) code. The proposed algorithms are superior to the error correcting algorithms of conventional systems such as DVD and BD.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.406-408
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• 2005

A passive Optical Network (PON) is famous for the most cost-efficient solution among the optical networks. This is because there is no active device between a central office and subscribers. A wavelength division multiplexing (WDM) offers each subscriber to feel unlimited bandwidth. A WDM-PON, however, has a cost problem that WDM-PON is used commercially. To solve this trouble, it is surveyed that a Sub-Carrier Multiplexing (SCM) used in a WDM-PON increases the number of subscribers. The performance of WDM/SCM-PON varies with various noises. The several FEC Codes can reduce the effects of noise and improve the performance of the system. Thus, Choosing a suitable FEC code is important work. This paper describes that a Reed-Solomon (RS) code is the most suitable code for WDM/SCM-PON at the object of 100 Mbps and $10^{-9}$ BER

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2000.11b
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• pp.119-124
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• 2000

하루 동안에도 인터넷의 QoS(Quality of Service)는 급속하게 변하므로 예측한다는 것은 불가능하며 열악한 인터넷망에서 효율적인 비디오 서비스를 제공하는데는 많은 어려움이 있다. 본 연구에서는 통신 환경이 열악한 인터넷 상에서 보다 효율적인 비디오 서비스를 제공하기 위한 적응적 QoS 관리 방법을 제시하고 확률적 분석과 시뮬레이션을 통해 서로의 결과를 비교한다. 첫째, 패킷 크기와 지연, 손실률의 관계와 하루 동안의 인터넷망의 QoS 변화를 파악한다. 둘째, Reed-Solomon code의 효율성을 확률적 분석을 통해 알아본다. 셋째, 인터넷망의 에러 패턴을 실제 시뮬레이션과 확률적 분석을 통해 비교한다.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1986.10a
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• pp.79-82
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• 1986

For the purpose of error correcting, a concatenated coding system has been proposed by cascading two codes-(7, 3) Reed-Solomon and (2, 1, 6) convolutional codes. As a result of the result of the computer simulation and the experiment, the (98.21) concatenated code has been show to be able to correct 12 randome error and 16 bust errors. When the channel error is about 1.2x10, this system indicats most efficient.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.35T no.1
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• pp.59-66
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• 1998

In this paper, the high-speed decoder for RS(Reed-Solomon) code, one of the most popular error correcting code, is implemented using VHDL. This RS decoder is designed in transform domain instead of most time domain. Because of the simplicity in structure, transform decoder can be easily realized VLSI chip. Additionally the pipeline architecture, which is similar to a systolic array is applied for all design. Therefore, This transform RS decoder is suitable for high-rate data transfer. After synthesis with FPGA technology, the decoding rate is more 43 Mbytes/s and the area is 1853 LCs(Logic Cells). To compare with other product with pipeline architecture, this result is admirable. Error correcting ability and pipeline performance is certified by computer simulation.