• Journal of information and communication convergence engineering
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• v.4 no.3
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• pp.97-100
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• 2006

In this paper, the transmission service for medical image is proposed via IEEE 802.15.4a on WPAN environment. Also, transmission and receiving performance of medical image using TH UWB-IR system is evaluated on indoor multi-path fading environment. On the results, the proposed scheme can solve the problem of interference from the medical equipment in same frequency band, and minimize the loss due to the indoor multi-path fading environment. Therefore, the transmission with low power usage is possible.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2000.11a
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• pp.12-15
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• 2000

In this paper, we have evaluated the performance of an OFDM system using hierarchical 16QAM (OFDM/HL-16QAM) for achieving high quality and high speed data and image transmission in multipath fading channel. The wireless channel for performance evaluation is assumed to include AWGN and two ray multipath fading. Through simulation we have obtained the BER performance of the system according to $E_{b}$, $N_{0}$, then compared the received image quality of proposed system with that of conventional system. From the result, it is shown that the OFDM/HL-16QAM system is more effective for data and image transmission.n.n.

• Journal of Internet Computing and Services
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• v.6 no.5
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• pp.133-141
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• 2005

In this paper, we designed about OFDM/QPSK image transmission system simulator embedded watermark in wireless channel environment. Channel environment used OFDM/QPSK still image transmission system considering AWGN, Multi-path fading. And, we analyzed effect of still image and watermark information in considered channel environment. Watermark information is coded by DM-SS (Direct Matric/Spread Spectrum) image watermarking scheme, Also, we used interleaving scheme for mitigating the degradation in watermarking data under wireless channel. As a results, we could know that PSNR of watermark image improved of about 1dB by 54.2371dB then apply interleaving in same multi-path fading environment.

• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.233-235
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• 2005

As a class of block codes, LDPC code with any desired code rate and code length is easily constructed. In OFDM system high data transmission is possible, In this paper, we examined the performance of four high-rate(0.75, 0.8, 0.889, 09412) LDPC coded OFDM in image transmission over Rayleigh fading channel. The high-rate of 0.9412 LDPC coded OFDM system obtained about 12dB gain over the OFDM at BER of $10^{-3}$ over Rayleigh fading channel. Also, the PSNR of code rate 0.9412 LDPC coded OFDM system at SNR=10dB is given by 18.8047dB where uncoded OFDM system gives 9.7303 dB.

• Journal of Advanced Navigation Technology
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• v.8 no.1
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• pp.1-9
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• 2004

In this paper, we have studied the reliable scheme for transmission of digital watermarking-inserted image data through wireless channel. Multimedia data and watermarking data are degraded because of the high BER (Bit Error Rate) and the effect of fading in wireless channel. We adapt the error correction scheme for mitigating the degradation in watermarking data. We have evaluated the error performance of watermarking data modulated by OFDM/16QAM and sent through Rician fading channel. The simulation results show that when error correcting scheme is used the watermarking data can be detected without severe error even though watermarking-inserted image data is suffered from severe damage.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.9
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• pp.43-48
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• 2012

This paper presents an iterative single-frequency continuous-wave signal-based I/Q regeneration method for improving image-rejection performance of multi-port junction-based direct receivers (MPDRs). This paper analyzes I/Q regeneration in MPDRs as I/Q mismatch compensation for direct conversion receivers. Based on the analysis, this paper evaluates the accuracy of I/Q regeneration in terms of the image-rejection ratio (IRR). The proposed method improves the IRR performance more than 20 dB compared to existing I/Q regeneration methods. Simulation results show that MPDRs using the proposed method can achieve an IRR of more than 70 dB, and that the bit error rate performances are almost the same as those of conventional coherent demodulators, even in fading channels.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.11
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• pp.1954-1959
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• 2006

In this paper, we proposed TH UWB-IR medical image transmission system using the IEEE an. 802.15.4a specification in WPAN environment. Also, we analyzed reception performance of wireless medical image transmission system in indoor multi-path fading environment using ITU-R M.1225 channel model. As a results, the proposed scheme can solve the problem of interference from the medical equipment in same frequency band, and minimize the loss due to the indoor multi-path fading environment. Therefore, the transmission with low power usage is possible.

• Journal of Radiation Protection and Research
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• v.19 no.1
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• pp.37-50
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• 1994

The experimental evaluation of exposure conversion formula using the relationship between optical photo-density, exposure dose and the quality of radiation characteristics of radiation energy to X-ray and ${\gamma}-rays$. The film badge dosimeter is analysed by exposure conversion formula which evaluate image fading characteristics for development time and directional characteristics for incident beam angle. In conclusion, exposure conversion formula evaluated of this study is satisfied with quality decision criterion of the film badge dosimeter.

• Journal of Information Processing Systems
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• v.10 no.2
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• pp.215-222
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• 2014

In this paper, we discuss optical encryption and decryption considering wireless communication channels. In wireless communication systems, the wireless channel causes noise and fading effects of the transmitted information. Optical encryption technique such as double-random-phase encryption (DRPE) is used for encrypting transmitted data. When the encrypted data is transmitted, the information may be lost or distorted because there are a lot of factors such as channel noise, propagation fading, etc. Thus, using digital modulation and maximum likelihood (ML) detection, the noise and fading effects are mitigated, and the encrypted data is estimated well at the receiver. To the best of our knowledge, this is the first report that considers the wireless channel characteristics of the optical encryption technique.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.1B
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• pp.114-124
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• 2002

In this paper, we proposed the image-based 3D ray tracing indoor propagation model using a patch scattering model for fading analysis of indoor propagation environments. An image-based 3D ray tracing technique is mainly used, which allows the rapid generation of the complex channel impulse response for any given location and polarization of transmitter and receiver. Due to the site specific nature of indoor environment, we took into account the location and the electrical properties of individual walls and objects such as windows, doors and plaster board in our propagation model. Besides, the 3D radiation beam-patterns and polarizations of arbitrary antennas were considered, and using patch scattering model we can consider the change of the polarization due to the scattering from the various indoor objects, like desks, chairs and etc. the are almost impossible to be modeled with the basic image-based ray tracing method. The model will predict the impulse response, the rms delay spread, the fading characteristics of the channel and performances of the polarization diversity schemes.