• Title, Summary, Keyword: QR code decoder

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Application Development and Performance Analysis of Smartphone-based QR Code Interpreter (스마트폰 기반의 QR코드 해석기 성능분석 및 응용개발)

  • Park, Chan-Jung;Hyun, Jung-Suk
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.10
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    • pp.2242-2250
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    • 2009
  • Recently, with the advance of Ubiquitous era, the types of services become diverse. Especially, due to the rapid development of mobile technology, the new functions of mobile phones are added and the new applications of mobile phones are developed actively. Among the various applications related to mobile phones, 2 dimensional barcode-based applications are increasing. 2 dimensional barcode is mostly used for the management of past record. However, by combing 2 dimensional barcode with mobile phones, the application areas of 2 dimensional barcode are expanded to the means of publicity for education, tourism, and festivals. In this paper, we develop a QR code decoder running on smartphones, which connects on-line and off-line. In addition, we modify our decoder by detecting the point for performance enhancement based on TRIZ. We compare our decoder with an open-source based decoder in terms of the code size of decoding and the speed of decoding in order to prove that our decoder has a better performance than the other. Finally, we introduce two applications: u-map and u-pamphlet as QR code applications.

Low Complexity Maximum-likelihood Decoder for VBLAST-STBC scheme using non-square O-STBC code rate $\frac{3}{4}$

  • Pham Van-Su;Le Minh-Tuan;Mai Linh;Yoon Gi-Wan
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.107-110
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    • 2006
  • This work presents a low complexity maximum-likelihood decoder for signal detection in VBLAST-STBC system, which employs non-square O-STBC code rate 3/4. By stacking received symbols from different received symbolduration and applying QR decomposition resulting the special format of upper triangular matrix R, the proposed decoder is able to provide not only ML-like BER performance but also very low computational load. The low computational load and ML-like BER performance properties of the proposed decoder are verified by computer simulations.

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Low-Complexity Maximum-Likelihood Decoder for VBLAST-STBC Scheme Using Non-square OSTBC Code Rate 3/4

  • Pham Van-Su;Le Minh-Tuan;Mai Linh;Yoon Gi-Wan
    • Journal of information and communication convergence engineering
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    • v.4 no.2
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    • pp.75-78
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    • 2006
  • This work presents a low complexity maximum-likelihood decoder for signal detection in VBLAST-STBC system, which employs non-square O-STBC code rate 3/4. Stacking received symbols from different symbol duration and applying QR decomposition result in the special format of upper triangular matrix R so that the proposed decoder is able to provide not only ML-like BER performance but also very low computational load. The low computational load and ML-like BER performance properties of the proposed decoder are verified by computer simulations.

A Variable Rate LDPC Coded V-BLAST System (가변 부호화 율을 가지는 LDPC 부호화된 V-BLAST 시스템)

  • Noh, Min-Seok;Kim, Nam-Sik;Park, Hyun-Cheol
    • Proceedings of the IEEK Conference
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    • pp.55-58
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    • 2004
  • This this paper, we propose vertical Bell laboratories layered space time (V-BLAST) system based on variable rate Low-Density Parity Check (LDPC) codes to improve performance of receiver when QR decomposition interference suppression combined with interference cancellation is used over independent Rayleigh fading channel. The different rate LDPC codes can be made by puncturing some rows of a given parity check matrix. This allows to implement a single encoder and decoder for different rate LDPC codes. The performance can be improved by assigning stronger LDPC codes in lower layer than upper layer because the poor SNR of first detected data streams makes error propagation. Keeping the same overall code rates, the V-BLAST system with different rate LDPC codes has the better performance (in terms of Bit Error Rate) than with constant rate LDPC code in fast fading channel.

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