• The KIPS Transactions:PartB
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• v.12B no.7 s.103
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• pp.745-754
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• 2005

This paper proposes an information hiding algorithm using channel coding technique which can be used to detect transmission errors and to protect copyright for MPEG-2 video The watermark signal is generated by applying copyright information of video data to a convolutional encoder, and the signal is embedded into macro blocks in every frame while encoding to MPEG-2 video stream In the decoder, the embedded signal is detected from macro blocks in every frame, and the detected signal is used to localize transmission errors in the video stream. The detected signal can also be used to claim ownership of the video data by decoding it to the copyright Information. In this stage, errors in the detected watermark signal can be corrected by channel decoder. The 3 video sequences which consist of 300 frames each are applied to the proposed MPEG-2 codec. Experimental results show that the proposed method can detect transmission errors in the video stream while decoding and it can also reconstruct copyright information more correctly than the conventional method.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.15 no.4
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• pp.230-236
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• 2022

In this paper, we propose an efficient concatenated code for both random and ISI errors on diffusion-based molecular communication channels. The proposed concatenated code was constructed by combining the ISI-mitigating code designed for ISI mitigation and the ISI-Hamming code strong against random errors, and the BER(bit error rate) performance was analyzed through simulation. In the case of the above M=1,200 channel environment, it was found that the error rate performance of the concatenated code follows the error rate performance of the ISI-mitigating code, which is strong against ISI, and follows the error rate performance of the ISI-Hamming code, which is strong against random errors, in the channel environment below M=600. In M=600~1,200, the concatenated code shows the best error rate performance among those of three codes, which is analyzed because it can correct both random errors and errors caused by ISI. In the following cases of below M=800, it can be seen that the error rate of the concatenated code and the ISI-mitigating code shows an error rate difference of about 1.0×10^-1 on average.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.11
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• pp.5370-5393
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• 2019

In this paper, we consider a two-way relay non-orthogonal multiple access (TWR-NOMA) system with residual hardware impairments (RHIs) and channel estimation errors (CEEs), where two group users exchange their information via the decode-and-forward (DF) relay by using NOMA protocol. To evaluate the performance of the considered system, exact analytical expressions for the outage probability of the two groups users are derived in closed-form. Moreover, the asymptotic outage behavior in the high signal-to-noise ratio (SNR) regime is examined and the diversity order is derived and discussed. Numerical simulation results verify the accuracy of theoretical analyses, and show that: i) RHIs and CEEs have a deleterious effects on the outage probabilities; ii) CEEs have significant effects on the performance of the near user; iii) Due to the RHIs, CEEs, inter-group interference and intra-group interference, there exists error floors for the outage probability.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.1
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• pp.80-93
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• 1997

This paper proposes a new technique of optimal codebook design in multistage gain-shape vector quantization (MS-GS VQ) for wireless image communication. An original image is divided into a smany blocks as possible in order to get strong robustness to channel transmission errors: the original image is decomposed into a number of subband images, each of which contains a sperate spatial frequency information and is obtained by the biorthogonal wavlet transform; each subband is separated into several consecutive VQ stages, where each stage has a residual information of the previous stage; one vector in each stage is divided into two components-gain and shape. But, this decomposition genrates too many blocks and it thus makes the determination of optimal codebooks difficult. We overcome this difficulty by evolving each block's codebook independently with different genetic algorithm that uses each stage's individual training vectors. Th eimpact of th eproposed VQ technique on the channel transmission errors is compared with that of other VQ techniques. Simulation results show that the proposed VQ technique (MS-GS VQ) with the optimal codebook designe dy genetic algorithms is very robust to channel transmission errors even under the bursty and high BER conditions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.5
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• pp.2332-2337
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• 2012

In this paper, a blind decision feedback algorithm is proposed based on the ideas that the derivative of information potential for constant modulus errors stays relatively undisturbed even when large output differences are induced by severe channel distortions and this property can prevent the error propagation that is one of the main problems in decision feedback structures. From the simulation results of the steady state MSE, the proposed blind equalizer algorithm with decision feedback has yielded about 3 dB performance enhancement in the channel model without spectrum nulls and above 9 dB in severe channel characteristics with spectrum nulls.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.1
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• pp.37-43
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• 2023

Compressed still image or video bitstreams require protection from channel errors in a wireless channel. Embedded Zerotree Coding(EZW), SPIHT could have provided unprecedented high performance in image compression with low complexity. If bit error is generated by dint of wireless channel transmission problem, the loss of synchronization on between encoder and decoder causes serious performance degradation. But wavelet zerotree coding algorithms are producing variable-length codewords, extremely sensitive to bit errors. The idea is to partition the lifting coefficients. A many partition of lifting transform coefficients distributes channel error from wireless channel to each partition. Therefore synchronization problem that caused quality deterioration in still image and video stream was improved.

• Proceedings of the IEEK Conference
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• 2001.06d
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• pp.13-16
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• 2001

In the Dedicated Short Range Communication (DSRC) system channel, a large number of bit errors occur because of Additive White Gaussian Noise (AWGN) and fading. When an image data is transmitted under the condition, reconstructed image quality is significantly degraded. In this paper, as an alternative to the error correcting code and/or automatic repeat request scheme, we propose an error recovery scheme for image data transmission. We first analyze how transmission errors in the DSRC system channel degrade image quality. Then, in order to improve image quality, we propose error resilient and concealment schemes for still image transmission using DCT-based fixed length coding, hamming code, cyclic redundancy check, and interleaver. Finally, we show its performance by an experiment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.11C
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• pp.1158-1163
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• 2002

In this paper it is focused on the relation between CLR (Cell Loss Ratio) and blocking probability, GoS(Grade of Services) parameters in the wireless ATM (Asynchronous Transfer Mode) access network which consists of access node and wireless channel. Traffic model of wireless ATM access network is based on the cell scale, burst scale and call connection level. The CLR equation due to buffer overflow for wireless access node is derived for CBR (Constant Bit Rate) traffic. The CLR equation due to random bit errors and burst errors for wireless channel is derived. Using the CLR equation for both access node and wireless channel, the CLR equation of wireless ATM access network is derived. The relation between access network CLR and blocking probability is analyzed for CBR traffic.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.4C
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• pp.364-370
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• 2010

In this paper, we propose a cooperative channel sensing scheme in the presence of feedback errors. Accurate local sensing results may not directly be applied to cooperative sensing due to feedback errors. We consider the cooperative channel sensing that utilizes local sensing results in good feedback channel condition. Finally, simulation results show that the proposed scheme can maximize the detection probability while guaranteeing desired false alarm probability.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.3
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• pp.155-157
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• 2014

In this paper, a novel codebook generation strategy is proposed. With the given codebooks, two codeword selection procedures are proposed and analyzed for generating the quantized multiple-input multiple-output (MIMO) channel state information (CSI). Furthermore, three different quantization and normalization strategies are analyzed. The simulation results suggest that the proposed 'quantized channel generation method 2' is the best strategy to reduce the quantization and normalization errors to generate the final quantized MIMO CSI.