• Journal of Internet Computing and Services
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• v.5 no.6
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• pp.59-66
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• 2004

In this paper, we propose a transmission rate prediction method of video data. The proposed method checks shot transition characteristics after dividing MPEG video data into a GoP unit and then uses Kalman filter. It used algorithm to detect shot transition information by high speed in compressed domain in order to check a correct shot transition of video data and classified into a abrupt shot transition type and a gradual shot transition type. Information to have been classifying is used as factors of Kalman filter and predicts a transmission rate of video data. Also, the proposed method decreased processing time with detecting shot transition and predicting a transmission rate of video data in compressed domain. It predicted a transmission rate with 96.2- 97.6% in the experiment that used three kinds of 911 1frames of different video data.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.60 no.4
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• pp.262-266
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• 2011

In high data-rate communication systems, encryption/decryption must be processed in high speed. In this paper, we implement CCM security mode which is the basis of security. Specifically, we combine CCM with AES block encryption algorithm in hardware. With the combination, we can carry out encryption/decryption as well as data transmission/reception simultaneously without reducing data-rate, and we keep low-power consumption with high speed by optimizing CCM block.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.6 s.324
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• pp.25-31
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• 2004

fireless LAN can offer high data rate communication between wireless terminals. In IEEE 802.11 wireless LAN, a basic service unit is called a Basic Service Set (BSS), which consists of one AP and more than one wireless terminals. Terminals far from the AP may not communicate with high data rate because signal strength is weakened as they move away from the AP. In this paper we propose a method to permit high speed data transmission by grouping terminals and by using part of wireless terminals as repeaters. We analyze the proposed and algorithm via simulations. Our proposed grouping mechanism is shown to be an effective way to increase the distance for high rate transmission.

• JSTS:Journal of Semiconductor Technology and Science
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• v.4 no.4
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• pp.275-279
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• 2004

A new burst mode clock and data recovery circuit is realized that improves the previousldy-known gated-oscilletor technique with half rate clock recovery, The circuit was fabricated with 0.25um CMOS technology, and its functions were confirmed up to 1 Gbps.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.9B
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• pp.785-791
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• 2006

A CF-Poll frame which contains the channel reservation time can be piggybacked in QoS-Data frame to increase the channel efficiency in HCCA. However, if any QSTA in the network uses the low physical transmission rate, the QoS-Data frame which includes the CF-Poll frame must be transmitted by the minimum transmission rate. Therefore, it can cause the decrease of the channel efficiency and the increase of the frame transmission delay for other traffic streams when any QSTA has the low physical transmission rate. In this paper, we define this phenomenon as the piggyback problem at the low physical transmission rate and evaluate the effect of this problem. In the simulation results, when a CF-Poll piggyback is used, the delay is increased about 25% if any QSTA has the low physical transmission rate, while the delay is decreased about 7.8% if all QSTA has the high physical transmission rate. We also found that the gain of the CF-Poll piggyback mechanism is achieved when all QSTA has higher physical transmission rate than 24 or 36Mbps.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.1
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• pp.414-435
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• 2017

As network adaptive streaming technology becomes increasingly common, transport protocol also becomes important in guaranteeing the quality of multimedia streaming. At the same time, because of the appearance of high-quality video such as Ultra High Definition (UHD), preventing buffering as well as preserving high quality while deploying a streaming service becomes important. The Internet Engineering Task Force recently published Multipath TCP (MPTCP). MPTCP improves the maximum transmission rate by simultaneously transmitting data over different paths with multiple TCP subflows. However, MPTCP cannot preserve high quality, because the MPTCP subflows slowly increase the transmission rate, and upon detecting a packet loss, drastically halve the transmission rate. In this paper, we propose a new multipath congestion control scheme for high-quality multimedia streaming. The proposed scheme preserves high quality of video by adaptively adjusting the increasing parameter of subflows according to the network status. The proposed scheme also increases network efficiency by providing load balancing and stability, and by supporting fairness with single-flow congestion control schemes.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.5
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• pp.996-1000
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• 2010

In order to apply VLC (visible light communication) in harsh environment of nuclear power plant in-containment building, the high luminance LEDs, which are key components of the VLC system, have been gamma irradiated at the dose rate of 4 kGy/h during 72 hours up to a total dose of 288 kGy. The radiation induced coloration effect in the high luminance LED bulb made of acryl or plastic material was observed. In the VLC wireless data transmission experiment using the high luminance LEDs irradiated by high dose rate gamma-ray, the radiation induced coloration effect of the high luminance LED bulb extended the communication distance compared to non-irradiated LEDs.

• Journal of Information Technology Services
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• v.9 no.2
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• pp.151-161
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• 2010

Recently, as the era of ubiquitous has arrived, an infrastructure for the short-distance wireless communication has been extended socially, and thus a variety of services are being proposed. The Multimedia Contents Delivery System using the ZigBee, in particular, has an important stance in enlargement of a variety of services in the aspect of individual-oriented service support though Wireless Personal Area Network (WPAN). Nonetheless, the ZigBee, or the IEEE 802.15.4 Standard, has many restrictions on the Multimedia Contents Delivery System due to the low data transport rate. In order to improve the ZigBee which presents a limit on the transport rate at the IEEE 802.15.4 Standard, this thesis has designed the burst mode which is a method of transmitting a certain amount of data in block units at a high speed without any stoppage until the completion of the transmission. Also, to provide a Multimedia Contents Delivery Service with an application of the normal data transmission mode, it improved the transmission performance of the ZigBee. In addition, for the Multimedia Contents Delivery Service under the ubiquitous environment, it designed and implemented a broadcasting Multimedia Contents Delivery System based on the ZigBee to conduct a comparative analysis on the data transmission performance according to the transmission method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.12B
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• pp.2109-2119
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• 2000

In this paper, the Packet CDMA Reservation ALOHA protocol is proposed to support the multi-traffic services such as voice and videophone services with handoff calls, high-rate data and low-rate data services efficiently on the multi-rate transmission in uplink cellular systems. The frame structure, composed of the access slot and the transmission slot, and the proposed access permission probability based on the estimated number of contending users for each service are presented to reduce MAI. The assured priority to the voice and the videophone handoff calls is given through higher access permission probability. And through the proposed code assignment scheme, the voice service can be provided without the voice packet dropping probability in the CDMA/PRMA protocols. The code reservation is allowed to the voice and the videophone services. The low-rate data service uses the available codes during the silent periods of voice calls and the remaining codes in the codes assigned to the voice service to utilize codes efficiently. The high-rate data service uses the assigned codes to the high-rate data service and the remaining codes in the codes assigned to the videophone service. Using the Markov-chain subsystem model for each service including the handoff calls in uplink cellular systems, the steady-state performances are simulated and analyzed. After a round of tests for the examples, through the proposed code assignment scheme and the access permission probability, the Packet CDMA Reservation ALOHA protocol can guarantee the priority and the constant QoS for the handoff calls even at large number of contending users. Also, the data services are integrated efficiently on the multi-rate transmission.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.7
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• pp.43-51
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• 2013

This paper describes the development of the telemetry link system for the high data rate transmission in high speed rocket application. In consideration of bandwidth efficiency, frequency selective fading and doppler frequency offset, we used DQPSK instead of PCM/FM which has been the primary modulation format in aeronautical telemetry. Also we used the spatial diversity with multiple receiving antennas to mitigate multipath interference which is the dominant channel impairment and the Turbo Product Code for Forward Error Correction to improve bit error rate performance.