• Journal of Broadcast Engineering
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• v.15 no.6
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• pp.868-875
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• 2010

AT-DMB was developed to raise the transmission rate of existing T-DMB with backward compatability. The transmission and hierarchical video service technique were legislated as Korean TTA standards, and other application service techniques including data services are being developed for the commercial service. In this paper, we consider the power of transmission power level of signals in Advanced Terrestrial Digital Multimedia System according to the constellation ratio. And we propose a new scheme for normalization of transmission signal power level in AT-DMB system. Adopting this scheme, the signal power level of hierarchical modulated signal can be uniform in AT-DMB system both for B Mode and Q Mode.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.2
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• pp.57-63
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• 2015

There are increasing demands for the transmission of high speed and non-compressed video informations. The video data usually compressed before transmission for reducing the data. And the received data uncompressed at a receiver, consequently the processing delay is unavoided. In this paper, we implement a 60 GHz band wireless transmission system for real time multimedia contents transmission, and successfully transmit the full HD class uncompressed video information at 4 Gbps with 20 m apart. Hence the non-compressed video data from a remote camera or a smart phone can be transmitted and displayed in a large screen in real time via the developed transceiver system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.8
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• pp.3904-3917
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• 2017

IP multimedia subsystem (IMS) is an open standardized architecture for delivering multimedia service over IP network in a route-agnostic manner. With the increasing popularity of conversational class service, the delivery of a traffic flow with a certain bandwidth demand over a single network path is either not possible or not cost-effective. Multipath transmission is considered to be a promising solution to provide high-quality delivery service. This paper proposes a software defined service overlay network (SDSON) based multipath transmission framework for IMS, which is complementary to existing network architecture. The framework transforms original two-party session negotiation into three-party session negotiation that supports participants to negotiate multipath transmission capacity and path information by signaling message. Based on existing IETF standards, SIP and SDP are scalable to support these functions. Finally, the proposed framework is fully implemented on open source platform and examined by experiments. Experimental results show that multipath-enabled IMS is an effective way to improve the delivery performance of conversational class service.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.12
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• pp.2323-2329
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• 2008

Advances in wireless communication and hardware technology have made it possible to manufacture high-performance tiny sensor nodes. More recently, the availability of inexpensive cameras modules that are able to capture multimedia data from the environment has fostered the development of Wireless Multimedia Sensor Networks(WMSNs). WMSN supplements the a advanced technique that senses, transmits, and processes the multimedia contents upon the text based traditional wireless sensor network. Since the amount of data which the multimedia contents have, is significantly larger than that of text based data, multimedia contents require lots of computing power and high network bandwidth. To process the multimedia contents on the wireless sensor node which has very limited computing power and energy, a technique for WMSN should take account of computing resource and efficient transmission. In the paper, we propose a new image compression technique YWCE for efficient compression and transmission of image data in WMSN. YWCE introduces 4 type of technique for motion estimation and compensation based on the Resolution Scalability of Wavelet. Experimental result shows that YWCE has high compression performance with different set of 4 type.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.652-657
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• 2004

As the real-time multimedia applications through Internet increase, the bandwidth available to TCP connections is oppressed by the UDP traffic, result in the performance of overall system is extremely deteriorated. Therefore, developing a new transmission protocol is necessary. The TCP-friendly algorithm is an example meeting this necessity. The TCP-friendly (TFRC) is an UDP-based protocol that controls the transmission rate based on the available round transmission time (RTT) and the packet loss rate (PLR). In the data transmission processing, transmission rate is determined based on the conditions of the previous transmission period. If the one-step ahead predicted values of the control factors are available, the performance will be improved significantly. This paper proposes a prediction model of transmission rate control factors that will be used for the transmission rate control, which improves the performance of the networks. The model developed through this research is predicting one-step ahead variables of RTT and PLR. A multiplayer perceptron neural network is used as the prediction model and Levenberg-Marquardt algorithm is used for the training. The values of RTT and PLR were collected using TFRC protocol in the real system. The obtained prediction model is validated using new data set and the results show that the obtained model predicts the factors accurately.

• ETRI Journal
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• v.26 no.4
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• pp.367-370
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• 2004

A new transmission system is necessary for the Digital Multimedia Broadcasting (DMB) service in Korea. Therefore, in this paper, we propose a new architecture for the implementation of a DMB transmission system based on Eureka-147. We describe the design and implementation of the Ensemble remultiplexer, which is essential to the proposed system for remultiplexing ETI frames and MPEG-2 transport streams. The proposed system provides a solution with high flexibility and low cost for multimedia broadcasting service. The functions of this transmission system have been verified by using our DMB receiver and other related systems.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2005.11a
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• pp.87-90
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• 2005

이 연구는 DVB에서 제안한 휴대형 디지털 TV 전송시스템인 DVB-H 시스템의 이동수신 성능을 분석하였다. DVB-H 시스템은 DVB-T 시스템을 휴대용으로 보완한 것으로 4K 모드, MPE-FEC 및 In-depth Interleaver 등이 추가되었으며, 이 연구는 각 추가 기능에 대하여 이동수신 성능향상 정도를 분석하였다. 이동수신 환경을 제공하기 위하여 COST 207을 적용하였다. 4K 모드는 최대지연시간이 긴 다중경로채널에서 8K 모드와 유사하고 2K 모드보다 훨씬 우수한 수신성능을 보였으며 도플러에 대해서는 2K와 8K 모드의 중간정도의 수신성능을 보여 주었다. MPE-FEC와 In-depth Interleaver는 이동수신채널에서 약간의 수신성능 향상을 보여 주었다.

• Journal of Korea Multimedia Society
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• v.18 no.4
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• pp.541-545
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• 2015

Wireless power transmission which can transmit the electrical power through the air is the promise technology. In this paper, the effects of wireless power transmission using magnetic resonance method have been studied on coil material, resonance frequency, and antenna type. We have found copper tube as a coil material had the better characteristics than that of enameled wire, and the optimal resonance frequency was 13.6MHz in the range of from 1MHz to 20MHz. And the double square spiral type antenna as a load coil was the best. The power transmission distance by magnetic resonance method with 13.6MHz was 150 cm.

• Journal of Korea Multimedia Society
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• v.18 no.8
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• pp.909-914
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• 2015

In wireless sensor networks, sensor nodes have a short transmission range and data is transferred from source to destination node using the multi-hop transmission. Sensor nodes are powered by battery and the link qualities are different, and the routing protocol in the wireless sensor network is one of the important technical issues. Multipath routing was proposed to reduce the data congestion and increase data throughput. In the multipath routing, however, each path can be interfered by the other path, and it can aggravate network performance. In this paper, we propose the multipath routing scheme for multi-rate wireless sensor networks. The multipath routing selects transmission paths to minimize transmission delay and path interference.

• Journal of Korea Multimedia Society
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• v.19 no.5
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• pp.924-931
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• 2016

In this paper, Various network adaptive MAC scheduling technique is proposed to effectively overcome limits of narrow bandwidth and low transmission speed in underwater. UPFC(Underwater Packet Flow Control) is a technique to reduce both the number of transmission and transmission time using three types (Normal, Blocked, Parallel) of data transmission. In this technique, the load information, in which a transmission node have, is transmitted to destination node using marginal bit in reserved header. Then the transmitted information is referred to determine weighting factor. According to the weighting factor, scheduling is dynamically changed adaptively. The performance of UPFC is analyzed and flow control technique which can be applied to Cluster Based Network and Ad Hoc network as well.