• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.38B no.7
• /
• pp.553-563
• /
• 2013

When the IEEE 802.11 wireless LAN-based broadcasting services, we use broadcast packets to broadcast multimedia contents to a large number of users using limited wireless resources. However, broadcast transmission is difficult to recover the loss packets compared with unicast transmission. Therefore, analysis of packet loss characteristics is required to perform efficient packet recovery. The packet loss in wireless transmissions is often bursty with high loss data rate. Even if loss patterns have the same average packet loss, they are different in the recovery rate of random loss and burst loss depending on the nature. Therefore, the analysis and research of the nature of the loss are needed to recover loss packets considering bursty characteristics. In this paper, we experimented Wi-Fi broadcast transmission according to transmission rate and analyzed bursty characteristics of loss patterns using 4-state markov model.

• Journal of Internet Computing and Services
• /
• v.20 no.2
• /
• pp.21-27
• /
• 2019

The terrestrial ATSC 3.0 broadcasting system, which is capable of converging broadcast and communication services, uses IP based technology for data transmission between broadcasting equipment. In addition, data transmission between broadcasting equipment uses IP-based technology like existing wired communication network, which has advantageous in terms of equipment construction and maintenance In case IP based data transmission technology is used, however, it may inevitably cause an error that a packet is lost during transmission depending on the network environments. In order to cope with a broadcasting accident caused by such a transmission error or a malfunction of a broadcasting apparatus, a broadcasting system is generally configured as a duplication, which can transmit a normal packet when various types of error may occur. By this reason, correction method of error packets and intelligent switching technology are essential. Therefore, in this paper, we propose a design and implementation of intelligent IP switch for Ensuring Reliability of ATSC 3.0 Broadcast Streams. The proposed intelligent IP consists of IP Stream Analysis Module, ALP Stream Analysis Module, STL Stream Analysis Module and SMPTE 2022-1 based FEC Encoding/Decoding Module.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.32 no.6A
• /
• pp.624-631
• /
• 2007

This paper presents inter-cell cooperation methods with two transmit antennas for broadcast services in a coded OFDM cellular system. In the method, cells are divided into multiple cell groups and a coded packet is partitioned into the subparts. Then, a different cell group and antenna combination is assigned to each subpart for transmission of two orthogonal branches of the diversity code. For the method, we derive the bound on the pairwise error probability to predict the coded performance and verify the performance gain of the proposed method through the simulation using turbo code and analytically derived bound.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.7A
• /
• pp.720-726
• /
• 2008

In this paper, we propose a multi-cell cooperation method for broadcast packet data services in the orthogonal frequency division multiplexing (OFDM)-based cellular system with multiple transmit antennas. In the proposed method, to transmit two streams of spatially demultiplexed or transmit diversity coded symbols over a number of transmit antennas, we divide a coded packet into multiple subparts to which different cell groups and antenna pairs are assigned. The proposed method enhances the diversity order by transforming the channel frequency responses of two symbol streams in each subpart of the broadcast packet. The increase in diversity of the proposed method is shown with the outage probability under various configurations.

• Journal of Broadcast Engineering
• /
• v.8 no.3
• /
• pp.259-267
• /
• 2003

In this paper, we propose a media processor to provide interactive services in mobile multimedia broadcasting environments. The proposed system Is designed to support various functionalities, such as generation of MPEG-4 IOD (Initial Object Descriptor)/OD(Object Descriptor)/BIFS (Binary Format for Scene) data, encapsulation of MPEG-4 AVC (Advanced Video Coding)/BSAC (Bit Sliced Arithmetic Coding) stream and generated IOD/OD/BIFS data into SL (Sync Layer) packet, packetization of SL packet into TS (Transport Stream) packet and multiplexing. The proposed media processor can provide MPEG-4 based interactive services for users.

• Journal of Broadcast Engineering
• /
• v.25 no.2
• /
• pp.252-264
• /
• 2020

Korea has launched the world-wide first terrestrial UHD broadcast services on May 31, 2017. While the existing HDTV broadcast services use MPEG-2 TS (Tranport Stream) standard for multiplexing and delivering compressed media with additional data, the terrestrial UHD broadcast services use MMT (MPEG Media Transport) standard, which is the next-generation standard beyond MPEG-2 TS. However, the production cost of UHD contents is so high that only a part of the total broadcast time is filled with UHD contents and the UHD time portion is planned to be gradually increased. On the other hand, the ATSC 3.0 standard that uses MMT is not yet used in full-fledged broadcast services in North America. Hence MMT broadcast equipment is still at an early stage with high prices. In this paper we implemented a multi-thread software running on an ordinary PC that can be utilized to realize a low-cost converter that converts the output of an existing MPEG-2 TS multiplexer to an MMTP (MMT Protocol) packet stream. We also verified the functionality of the software through experiments.

• Journal of Broadcast Engineering
• /
• v.8 no.1
• /
• pp.45-53
• /
• 2003

Traffic specification plays a crucial role in the resource reservation for video services over the packet-switching networks. The current development of QoS-guaranteed service still leaves a wide space for the selection of traffic specification. We propose a new method to estimate the traffic specification of variable-bit-rate (VBR) video for deterministic service. The method is based on the concept of empirical envelope and the delay bound. The solution shows to be simple yet it provides excellent network utilization.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2002.11a
• /
• pp.85-90
• /
• 2002

Traffic specification plays a crucial role in the resource reservation for video services over the packet-switching networks. The current development of QoS-guaranteed service still leaves a wide space for the selection of traffic specification. We propose a new method to estimate the traffic specification of variable-bit-rate (VBR) video for deterministic service. The method is based on the concept of empirical envelope and the delay bound. The solution shows to be simple yet it provides excellent network utilization.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2004.05b
• /
• pp.475-478
• /
• 2004

In this paper, a CSSMA/AI MAC protocol for data services in packet CDMA network is presented. The proposed protocol is based on the code status sensing and reservation scheme. In the proposed protocol, the base station broadcast the rode status on a frame-by-frame basis just before the beginning of each preamble transmission, and the mobile station transmits a preamble for reserving a randomly selected code based on the received code status. After having transmitted the preamble, the mobile station listens to the downlink of the selected rode and waits for the base station reply. If this reply indicates that the code has been correctly acquired, it continues the packet transmission lot the rest of the frame. If there are other packets waiting for transmission, the base station broadcasts the status of the code as reserved, and the mobile station transmits a packet through the reserved code for the successive frames.

• Journal of Broadcast Engineering
• /
• v.12 no.2
• /
• pp.80-92
• /
• 2007

IPTV Services that is representative union service of broadcasting and telecommunication need guarantee of QoS, efficiency of multicasting, and hish bandwidth on the network. Because typical TDM based metro transport network was designed by transporting fixed voice traffic with stable and recovering method, it has a defect of bottleneck and a waste of bandwidth for acceptance of data traffic with burst feature and then all of data are treated equally at the transport network because it cannot classify between advanced high end service and best effort low end service. for completely resolving this kind of problem about increasing burst traffic and QoS issues, firstly we need to new design for transport network. This paper presents transformation method from TDM based metro transport network to packet based transport network and advantage and effectiveness of packet based transport network and also indicates technical factor and characters about method of packet transport system. As a result of research, the Packet Transport System, which is a transmission network for packet delivery, take in not only a specific character of legacy TDM but QoS, Multicast and high bandwidth, then, it is able to keep an effective bandwidth and a stabilized performance of packet transmissions. Additionally, if a fault be occurred on an optical link, the system is able to guarantee a differential QoS by an each service class using an algorithm to make certain of a traffic existence and contain a protective mechanism.