Search

The European Commission requires all European Union (EU) Member States to use telecommunications networks to alert the population of an ongoing crisis or an upcoming threat by June 2022. Public Warning System in Long Term Evolution (LTE) and 5G System currently supports a text-based warning using Cell Broadcast technology. Cell Broadcast does not support multimedia warning message delivery. This paper analyses requirements that need to be fulfilled to support multimedia warning message delivery in the 5G System and describes trials of a broadcast multimedia public warning alert system. The trials demonstrate delivery of multimedia public warning messages using Evolved Multimedia Broadcast Multicast Service (eMBMS), dynamic spectrum management and bonded connections. By using eMBMS the public warning messages can be sent with additional robustness and in multicast mode, resulting also in less congestion to the network as the messages do not need to be sent separately to each user. Dynamic spectrum management system allows to dynamically obtain spectrum resources for the public warning system messages and the bonded connections improves the throughput and reliability of the delivery by combining the capacity of several different networks. [ABSTRACT FROM AUTHOR]

STiMi is a mobile multimedia broadcasting trade standard that was released by the Chinese State Administration of Radio Film and Television in 2006. This paper details the algorithm research and development work on the acquisition for STiMi. First, the STiMi physical layer is briefly reviewed. secondly, individual algorithms, including time slot detection, fractional frequency offset estimation, integer frequency offset estimation and fine timing synchronization are discussed with simulation results presented. An implemented STiMi receiver prototype is also introduced with a focus on the acquisition algorithms implementation. Finally, the whole acquisition procedure is summarized. Acquisition algorithms and structures presented in this paper are adopted for prototyping and perform well. [ABSTRACT FROM AUTHOR]

This paper describes a channel estimation algorithm for the advanced terrestrial digital multimedia broadcasting (T-DMB) transmission system which is fully backward compatible with the conventional T-DMB standard. The advanced T-DMB has enhanced features which provide higher transmission data rate for increasing program channel capacity and better multimedia A/V service quality than the conventional T-DMB system by adopting a hierarchical modulation and scalable audio/video CODEC. To support the higher data rate transmission for the advanced T-DMB, high performance channel estimation and equalization techniques should be adopted into the advanced T-DMB receivers. In this paper, we propose a new channel estimation technique for the Advanced T-DMB to compensate channel distortion under dynamic multipath environment. [ABSTRACT FROM AUTHOR]

In this paper, we describe how the transmission technologies developed for over-the-air Digital Television broadcasting could be used to offer Interactive Television and Internet Multimedia Service. We propose to use the ATSC-DTV system for the downlink and DVB-RCT standard to implement a wireless return channel. This paper will also present some technical aspects of the system implementation. [ABSTRACT FROM AUTHOR]

The objective of this work is to research and analyse the performance of Cyclic Delay Diversity (CDD) with two transmit antenna on DVB-H systems operating in spatially correlated channel. It is shown in this paper that CDD can achieve desirable transmit diversity gain over uncorrelated channel with or without receiver diversity. However, in reality, the respective signal paths between spatially separated antennas and the mobile receiver is likely to be correlated because of insufficient antenna separation at the transmitter and the lack of scattering effect of the channel. Under this spatially correlated channel, it is apparent that CDD cannot achieve the same diversity gain as obtained under the uncorrelated channel. In this paper, a new upper bound on the pairwise error probability (PEP) of the CDD with spatial correlation of two transmit antennas is derived. The upper bound is used to study the CDD theoretical error performance and diversity gain losses over a generalized spatially correlated Rayleigh channel. This theoretical analysis is validated by the simulation of DVB-H systems with two transmit antennas and the CDD scheme. Both the theoretical and simulated results give the valuable insight that the CDD ability to perform well with a certain amount of channel correlation. [ABSTRACT FROM AUTHOR]

Digital satellite multimedia broadcasting services in Europe are specified in the Mobile Satellite Services (MSS) frequency band by two recently developed standards, namely the European Telecommunications Standards Institute (ETSI) Satellite Digital Radio (SDR) and the Digital Video Broadcasting—Satellite services to Handhelds (DVB-SH) standards. Commercial deployment of operational systems based on these standards is foreseen in the coming years targeting mainly six large European markets. For these standards, a state-of-the-art channel code is deployed based on the 3rd Generation Partnership Project 2 (3GPP2) specifications having a wide range of coding rates. The purpose of this paper is twofold: (i) It studies and compares, for the first time, the Bit Error Rate (BER) performance of the 3GPP2 turbo code used in the aforementioned systems, in order to serve as a benchmark for system design engineers; and (ii) It investigates novel alternative channel coding schemes, including other state-of-the-art turbo code configurations and also Low-Density Parity-Check (LDPC) codes with linear-time encoding, such as the Irregular Repeat-Accumulate (IRA) codes, in order to improve the performance and/or reduce the complexity in future mobile satellite broadcasting systems. Extensive performance evaluation results in the Additive White Gaussian Noise (AWGN) and uncorrelated Rayleigh/Rician fading channels have shown that the use of turbo codes with higher number of states improves performance against the 3GPP2 turbo codes of up to 0.25 dB but the decoding complexity is almost doubled. Furthermore, the use of duo-binary turbo codes reduces decoding latency and makes them more robust in puncturing with performance improvement against the 3GPP2 turbo codes of up to 0.3 dB but performance degrades at very low coding rates. On the other hand, the use of Rate Compatible (RC)-IRA codes results in smaller performance improvement against the 3GPP2 turbo codes, i.e. up to 0.1 dB, but rate compatibility is used to obtain different coding rates with simple puncturing/extending method. [ABSTRACT FROM PUBLISHER]

This paper presents an efficient VLSI architecture and implementation for LDPC decoder used in China Multimedia Mobile Broadcasting (CMMB) systems. An area-efficient layered decoding architecture based on min-sum algorithm is incorporated in the design. A novel split-memory architecture is developed to efficiently handle the weight-2 submatrices that are rarely seen in conventional LDPC decoders. In addition, the check-node processing unit is highly optimized to minimize complexity and computing latency while facilitating a reconfigurable decoding core. The proposed design is implemented using 90 nm CMOS technology with the core area of approximately 4.4 mm² and the standard supply voltage 1.0 V. The decoder can achieve the maximum throughput of 228 Mb/s for rate ½ and 342 Mb/s for rate ¾ at 15 iterations of layered decoding. Therefore, it can be deployed on the CMMB mobile platform. [ABSTRACT FROM AUTHOR]

The MobileTV, IPTV, and DVB standards (DVB-HIT) have been defined to offer mobile users interactive multimedia services with quality of service (Q0S) consistency analogous to TV services. However, the market has yet to provide effective and economical solutions for the real-time delivery of such services to the corresponding transmitters over multi-domain IP networks. The monitoring system proposed in this paper enables the Q0S in the IP networks involved in the delivery of real-time multimedia content to the transmitters to be ascertained. The system utilizes the Q0S parameters defined in MPEG-2 Transport Streams to detect problems occurring in the heterogeneous multi-domain IP networks. The ability to detect problems having an adverse effect on Q0S allows appropriate control actions to be determined to recover the QoS across the composite IP network. The design and implementation of the proposed QoS-Monitoring system (QoS-MS) is presented, followed by analysis of experimental results that demonstrate the feasibility of the system. [ABSTRACT FROM AUTHOR]

Commercial terrestrial digital multimedia broadcasting (T-DMB) service was launched in the Republic of Korea. Reflecting recent demands of high quality video, Advanced T-DMB(AT-DMB) adopting a hierarchical modulation is being developed as the way to increase the payload data. Based on the AT-DMB system, this paper proposes a method to provide increased video quality with high spatial resolution. By using the emerging H.264/MPEG-4 AVC amendment 3 scalable extension (SVC), the proposed method is able to support high spatial resolution as well as the currently serviced spatial resolution while retaining the backward compatibility to T-DMB. In the experimental results, the benefits in terms of coding efficiency and spatial scalability are proven in comparison with the conventional T-DMB and alternative methods to provide a high spatial resolution video. [ABSTRACT FROM AUTHOR]

Histogram equalization is a simple and effective method for contrast enhancement as it can automatically define the intensity transformation function based on statistical characteristics of the image. However, it tends to alter the brightness of the entire image, which it is not suitable for consumer electronic products, where preservation of the original brightness is essential to avoid annoying artifacts. This paper presents a new contrast enhancement method for generalization of the existing bihistogram equalization (BHE) and recursive mean-separate histogram equalization (RMSHE) methods. The proposed method is referred to gain-controllable clipped histogram equalization (GC-CHE) to provide both histogram equalization and brightness preservation. More specifically adaptive contrast enhancement is realized by using clipped histogram equalization with controllable gain. The clipping rate is determined based on the mean brightness, and the clipping threshold is determined based on the clipping rate. The clipping rate is adaptively controlled to enhance the contrast with preserving the mean brightness. It is mathematically proven that the mean brightness of the output image converges to that of the input image with adaptive controlled. Simulation results show that the proposed GC-CHE method outperforms existing histogram-based methods, such as HE, BHE, and RMSHE, in various situations. [ABSTRACT FROM AUTHOR]

In this paper, we consider a peer-to-peer (P2P) network, where multimedia streams are broadcast by matched peers based on their resource reciprocation profiles. We propose a new framework where each peer creates a coalition of matched peers with which it can exchange resources in order to improve its utility. The utility is determined based on explicit consideration of the peer's multimedia attributes and the quality derived by the peers' reciprocation behavior. We adopt the proportional bargaining solution to negotiate the upload bandwidth among the matched peers. Proportional bargaining allows to determine each peer's optimal (in a Pareto optimal sense) upload rates in a coalition in terms of its utility impact. The impact of an incoming peer on the coalition value, which represents the collective utility achieved by the peers in a coalition, is assessed by explicitly investigating the coalition value improvement. Finally, our results show that the proposed coalition-based resource reciprocation can improve the resource allocation/scheduling algorithms deployed in existing P2P systems such as BitTorrent and CoolStreaming. We also discuss how the proposed resource reciprocation approach can be implemented in other multimedia broadcasting applications. [ABSTRACT FROM AUTHOR]

With the emergence of new TV media such as digital cable and satellite, the task of finding one's favorite program among hundreds of channels becomes a time consuming job. Furthermore, the channel zapping time of DTV is much longer than that of analogue one. To relieve the time overhead in channel navigation, this paper presents an intelligent channel navigation scheme for DTV channel selectors. The proposed navigation scheme analyzes each person's previous watching behavior in terms of recency and frequency, and then utilizes this information in the control of the up-down channel selector. Simulation studies show that the proposed scheme reduces the seek distance of the DTV channel navigation system by up to 68.7% under various conditions. [ABSTRACT FROM AUTHOR]

Convergence between broadcasting services and telecommunication services and provisioning of rich media services are two major requirements that recent mobile broadcast TV services try to satisfy. Although there exist independent technologies and international standards for each of the requirements, few efforts have been paid for providing solutions supporting these requirements together. In this paper, we present a standard-based implementation for mobile handsets in support of rich media enabled mobile broadcast TV services. [ABSTRACT FROM AUTHOR]

This paper deals with cross-layer measurements for the efficient analysis of Digital Video Broadcasting-Terrestrial (DVB-T) system performance. In particular, valuable relation- ships between some cross-layer DVB-T system parameters are investigated through measurements conducted at the physical and application layers. Specifically, channel power, error vector magnitude, and modulation error ratio are assessed at the physical layer, whereas objective video quality indices are estimated at the application layer. To this aim, a number of real-life experiments are executed through a purposely developed testbed that enlists a suitable DVB-T transmission platform and real-life receivers. The ultimate goal is to highlight the importance of cross-layer measurements in the analysis and troubleshooting of DVB-T system operation and to show how to deduce from such measurements practical information and hints to be profitably used in the design and setup of any DVB-T broadcasting system. [ABSTRACT FROM AUTHOR]

Current satellite digital broadcasting transmission system "ISDB-S " employs digital modulation schemes, BPSK, QPSK, and 8PSK combined with a concatenated code consists of convolution code and Reed- Solomon code. While, in recent years, transmission systems adopted LDPC codes have been developed. Multi-level digital modulation schemes combined with LDPC codes can achieve more efficient transmission. In this paper, we propose a new transmission system employed LDPC, multi-level modulation and advanced TMCC signal. [ABSTRACT FROM AUTHOR]

The interactive media platform(IMP) scheme proposed here provides an efficient solution for interactive digital TV in back-end. The platform actually integrates traditional TV guide system, interactive application execution system and digital video recorder(DVR) system together. The IMP consists of hardware infrastructures and middleware-based system software. This paper addresses a reference solution for interactive digital TV receiver that compliant with DVB-MHP. The architecture of IMP is proposed. The hardware architecture and middleware-based system software architecture are also presented respectively. In broadcast networks, all data including service information and interactive applications are transmitted from front-end to back-end periodically. Thus, broadcast latency is introduced to the platform while receivers processing broadcast data. Considering that broadcast latency has great influences to the platform performance, optimized strategies to reduce such latency while implementing is described in detail. The proposed platform has been implemented and the experimental result shows a good performance. [ABSTRACT FROM AUTHOR]

In this paper, a novel high-performance 8k-point fast Fourier transform(DFT) processor architecture for OFDM digital video broadcasting(DVB) is proposed based on a novel radix-8 FFT architecture. Distributed arithmetic(DA) is used to implement the basic 8-point FFTs directly, where the hardware cost of complex multipliers and adders can be greatly reduced. The twiddle multiplications are performed by CORDIC-based twiddle multipliers. The results show that the proposed processor architecture can greatly save the area cost while keeping a high-speed processing speed, which may be attractive for many real-time DVB-T systems. [ABSTRACT FROM AUTHOR]

The Hybrid Fiber Coax (HFC) is a modern broadband access network, providing advanced interactive services such as Internet access, digital interactive television and cable telephony. The edge costs dominate the cost of launching new services, at the time of deployment (CapEx) as well as for maintenance (OpEx). Therefore next-generation edge devices aim at the convergence of these services and their platforms into a single multi-service infrastructure, thus sharing resources and bandwidth. The focus of this paper is on the HFC access network design for bandwidth-intensive TV services, bringing standard as well as switched broadcast technologies into play. Standard broadcast TV service deployments, offered through the Digital Video Broadcast (DVB) platform, require low installation costs, but the bandwidth consumption increases linearly with the number of available TV channels, even for very unpopular channels. Switched broadcast TV channels, offered on the (Euro-) DOCSIS platform together with other interactive unicast services such as Video on Demand, are only streamed to a node on the HFC access network if they are requested locally, thus limiting bandwidth consumption for less popular channels. We present an access network design tool, based on an analytical TV traffic model, minimizing the installation cost on the edge devices and study the influence of the most important traffic and content parameters. [ABSTRACT FROM AUTHOR]

In this paper, we introduce a new scheme to improve the performance of the terrestrial - digital multimedia broadcasting (T-DMB) system, which exploits the burst error characteristics at the output of the convolutional decoder and the properties of the Reed-Solomon (RS) decoder to correct more errors by predicting erasures in each RS packet in advance as many as possible before decoding in the RS decoder. Simulation results show that the proposed scheme yields performance gain of around 1 dB at BER of 10-8 which can result in the extended coverage area of the T-DMB system. [ABSTRACT FROM AUTHOR]

In this paper, we describe a new 1/4 rate robust modulation techniques for Enhanced-xVSB system which is fully backward compatible with ATSC 8-VSB standard. 1/4 rate mode Enhanced-xVSB system provides broadcasters with a wide choice of trade-offs of data rate vs amount of robustness of enhanced data for pedestrian/mobile services. Lab test results of proposed Enhanced-xVSB 1/4 rate mode robust stream is a significantly improved multipath as well as AWGN reception performance for Enhanced-xVSB receiver. We suggest an Enhanced-xVSB terrestrial broadcasting system for ATSC HDTV and pedestrian/portable TV simultaneous broadcasting service providing. [ABSTRACT FROM AUTHOR]

In this paper, novel and yet simple techniques are presented to minimize the error propagation caused by the large precursors and postcursors of the decision feedback equalizer (DFE) in 8VSB DTV system. A technique that selects a reference tap (symbol timing of DFE) from an estimated channel impulse response (CIR) is presented to minimize the effect of the large precursors. Another technique that selects the reference tap position, i.e., decision delay in a feedforward filter (FFF), from the estimated CIR and the amplitude of the selected reference tap is proposed to minimize the effect of large postcursors. The combined structure of a feedback filter (FBF) and Viterbi decoder for use in 8VSB DTV system is also proposed to replace the past unreliable decision symbols in FBF as well as to reduce the decision error probability. Simulation results show that our proposed DFE can prevent effectively the error propagation, in particular, by changing the reference tap and its position in FFF according to the channel condition. It is also shown that an echo removing capability of the proposed DFE, where 400 and 620 taps are used for the FFF and FBF, respectively, is greater than that of conventional DFEs by about -20 μs in the single pre-echo of -10 dB channel and by about 10 μs in the single post-echo of -1 dB channel. [ABSTRACT FROM AUTHOR]

It has been demonstrated that turbo codes substantially outperform other codes, e.g., convolutional codes, both in the non-fading additive white Gaussian noise (AWGN) channel as well as multiple-transmit and multiple-receive antenna fading channels. Moreover, it has also been reported that turbo codes perform very well in fast fading channels, but perform somewhat poorly on slow and block fading channels of which the broadband fixed wireless access (FWA) channel is an example. In this paper, we thoroughly compare the performance of turbo-coded and convolutional-coded broadband FWA systems both with and without antenna diversity under the condition of identical complexity for a variety of decoding algorithms. In particular, we derive mathematical expressions to characterize the complexity of turbo decoding based on state-of-the-art Log-MAP and Max-Log-MAP algorithms as well as convolutional decoding based on the Viterbi algorithm in terms of the number of equivalent addition operations. Simulation results show that turbo codes do not offer any performance advantage over convolutional codes in FWA systems without antenna diversity or FWA systems with limited antenna diversity. Indeed, turbo codes only outperform convolutional codes in FWA systems having significant antenna diversity. [ABSTRACT FROM AUTHOR]

In a world driven by the accessibility of data for business, for communication and entertainment, but one populated by an increasingly nomadic society, it is no surprise that the appetite for wireless services continues to grow. The limitations of existing technologies however, particularly for wireless multi-casting and broadcasting, suggest that new approaches are needed to allow users to access services in the all wireless world. A popular approach for improving wireless services proposes to equip Mobile Terminals (MTs) with more than one radio interface to enable access to services in an always best connected paradigm. One such architecture envisages a co-operating overlay network, or inter-network, that comprises of a cellular telephony network and a digital broadcasting network. MTs in the inter-network have two corresponding radio interfaces and co-operation between the networks provide the user with seamless access to diverse services across the inter-worked platform. In this paper, we introduce novel location management proposals for co-operating overlay networks that incorporate a unidirectional broadcast overlay and provide a cost and latency analysis of the schemes. Our cost analysis demonstrates the soundness of the techniques and the value of the analyses as comparative evaluation tools. In particular, it is shown that there are a wide range of realistic operating conditions where the novel proposals presented here provide an optimum performance in cost terms. [ABSTRACT FROM AUTHOR]

Video broadcasting has been proved to be an efficient technique to increase the scalability of a video-on-demand (VoD) system. In this paper, we address the problems in providing interactive functions for VBR encoded videos in a broadcast VoD system. A traffic smoothing scheme is proposed to support the VCR functions in delivering VBR videos over CBR channels by the staggered broadcasting protocol. By introducing a small buffering delay, the customers are able to join back to the broadcasting groups after the interactive functions. A system model is then developed to determine the optimal parameters such that the system can meet the delay requirement as well as provide the expected quality of service to the customers. The results show that the proposed system framework is very efficient in terms of bandwidth requirement and buffering delay to provide interactive VoD services. [ABSTRACT FROM AUTHOR]

In this paper we present the results of a study that examines the user's perception—understood as both information assimilation and subjective satisfaction—of multimedia quality, when impacted by varying network-level parameters (delay and jitter). In addition, we integrate eye-tracking assessment to provide a more complete understanding of user perception of multimedia quality. Results show that delay and jitter significantly affect user satisfaction; variation in video eye path when either no single/obvious point of focus exists or when the point of attention changes dramatically. Lastly, results showed that content variation significantly affected user satisfaction, as well as user information assimilation. [ABSTRACT FROM AUTHOR]

Digital multimedia broadcasting (DMB) is a reliable multi-service system for mobile and portable receivers. DMB system allows interference-free reception under the conditions of multipath propagation and transmission errors using coded orthogonal frequency division multiplexing modulation (COFDM) and unequal error protection (UEP) scheme. For error correction of portable DMB receivers, punctured convolutional code and viterbi decoder is developed but it needs lots of computations for real-time operation. So, it is desired to design a high speed and low-power hardware scheme for viterbi decoder. This paper proposes a combined add-compare-select (ACS) and path metric normalization (PMN) unit using pre-computation technique for DMB system. The proposed PMN unit reduces the critical path by applying fixed value selection algorithm using the comparison tree properties. We also propose an ACS structure using the decomposition and pre-computation technique for reducing the complexity of the adder, comparator and multiplexer. Simulation results shows that area, gate delay and power consumption are reduced about 3.78 %, 23.80 %, and 12.22 %, respectively. [ABSTRACT FROM AUTHOR]

In traditional mobile streaming networks such as 3G cellular networks, all users pull streams from a server. Such pull model leads to high streaming cost and problem in system scalability. In this paper, we propose and investigate a fully distributed, scalable, and cost-effective protocol to distribute multimedia content to mobiles in a peer-to-peer manner. Our protocol, termed Collaborative Streaming among Mobiles (COSMOS), makes use of broadcasting and data sharing to achieve high performance (in terms of delay, cost fairness, stream continuity, etc.). In COSMOS, only a few peers pull video descriptions from base stations. Using a free broadcast channel (such as Wi-Fi and Bluetooth), they share the streams to nearby neighbors. As a result, COSMOS greatly reduces the streaming cost and cellular bandwidth requirement. Furthermore, as video streams are supplied by multiple peers, COSMOS is robust to peer failure. Since broadcasting is used to distribute video data, COSMOS is highly scalable to large number of users. In COSMOS, peers autonomously determine whether to broadcast packets or not in order to efficiently use of the channel bandwidth. By taking turns to pull descriptions, peers can effectively share, and hence substantially reduce, streaming cost. As broadcast scope is small and peers can often obtain a number of streams from its neighbors, COSMOS achieves low delay and excellent stream continuity. [ABSTRACT FROM AUTHOR]

In this paper an integrated satellite-terrestrial network architecture offering SDMB (Satellite Digital Multimedia Broadcast) services to mobile users through the satellite or terrestrial UMTS segment, is studied to test a novel Demand Sensitive Model (DSM). The DSM is proposed for tuning price service over SDMB system to offer a price discount to large amount of users while maintaining profit for the service provider. The simulations have been carried out to show the goodness of the proposed model within the system architecture; moreover the model, based on simple parameters, is very flexible and can be easily integrated in a ‘Price Adapter’ module making the offered service attractive for end users and in the same time profitable for the satellite operator. [ABSTRACT FROM AUTHOR]

TV is regarded as a key service for mobile devices. In the past, Mobile TV was often associated with broadcast transmission. However, unicast technology is sufficient in many cases, especially since mobile users prefer to access content on-demand, rather than following a fixed schedule. In this paper we will focus on 3G mobile networks, which have been primarily optimized for unicast services. Based on a traffic model we will discuss the capacity limits of 3G networks for unicast distribution of Mobile TV. From the results it can be concluded that the capacity is sufficient for many scenarios. In order to address scenarios in which broadcast is a more appropriate technology, 3GPP has defined a broadcast extension, called Multimedia Broadcast Multicast Service (MBMS). MBMS introduces shared radio broadcast bearers and has thus the capabilities of a real broadcasting technology. We will give a short overview about MBMS including a discussion on MBMS capacity. Since MBMS is primarily a new transport technology, additional application and service layer technologies are required, like electronic service guide and service protection. These mechanisms are standardized by the Open Mobile Alliance (OMA) and are favorably combined with MBMS or 3G unicast distribution in order to create complete end-to-end solutions. In order to optimize a system for delivery of broadcast services over 3G networks, the advantages of broadcast and unicast should be combined. We argue that hybrid unicast-broadcast delivery offers the best system resource usage and also the best user experience, and is thus favorable not only for broadcast delivery in 3G net- works, but actually also for non-cellular broadcast systems like DVB-H or DMB. [ABSTRACT FROM AUTHOR]

A new mobile multimedia broadcasting service using a geostationary satellite was launched on May 2005 in Korea. The Satellite Digital Multimedia Broadcasting (S-DMB) system provides high quality audio, video and data broadcasting services to handheld and mobile receivers. S-DMB is a personal digital media which can provide bidirectional and interactive services via the convergent platform of broadcasting and communication. At present, TU Media, the only S-DMB service provider in Korea, provides 15 TV channels, 19 audio channels, and 3 data channels. The number of subscribers is about 890,000 by Nov. 2006. Thousands of low power gap fillers (repeaters) have been installed in the shadowed or blocked reception areas in the metropolitan Seoul. This paper presents the system requirements, standards and specifications, architecture, and service status of S-DMB in Korea. Comparisons with other satellite broadcasting systems and the services are also presented. Link budget analysis on the direct path down-link (satellite to receivers) and relay path feeder link (gap fillers to receivers) are carried out in order to ensure the satisfactory QoS. [ABSTRACT FROM AUTHOR]

Commercial terrestrial digital multimedia broadcasting (T-DMB) service was launched on December 1st, 2005, in the Seoul metropolitan area of the Republic of Korea. As the world's first commercial terrestrial mobile multimedia broadcasting service, T-DMB garnered huge attention in the field of mobile broadcasting. This paper presents the history, system, and services of T-DMB. [ABSTRACT FROM AUTHOR]

As different types of wireless networks are converging into an all-IP network, i.e., the Internet, it can be expected that in the near future video-on-demand (VoD) will be widely applied to many interesting services, and users can access these services using heterogeneous terminals via heterogeneous wired/wireless access networks. Many periodic broadcasting protocols have been proposed to reduce the implementation cost of VoD systems. However, most of the protocols assumed homogeneity for user terminals, while in practice, user terminals are usually quite different in their processing power, buffer space, and power. To address this problem, a few periodic broadcasting protocols providing the same video quality for all heterogeneous clients have been proposed recently. In this paper, we proposed a novel heterogeneous VoD broadcasting technique called Catch and Rest (CAR) to accommodate bandwidth heterogeneity without sacrificing user video quality. Then, we provide mathematic analysis to calculate the client bandwidth and buffer space requirements of CAR. Finally, we present our performance evaluation results for CAR. Our results show that under the same system resources (i.e., server and network bandwidth), CAR provides more uniform and acceptable service latency for all heterogeneous clients compared to previous works. [ABSTRACT FROM AUTHOR]

Intercarrier interference is deemed as one of the crucial problems in the wireless orthogonal frequency division multiplexing (OFDM) systems. The conventional ICI mitigation schemes involve the frequency-domain channel estimation or the additional coding, both of which require the spectral over- head and hence lead to the significant throughput reduction. Besides, the OFDM receivers using the ICI estimation rely on a large-dimensional matrix inverter with high computational complexity especially for many subcarriers such as digital video broadcasting (DVB) systems and wireless metropolitan-area net- works (WMAN). To the best of our knowledge, no semi-blind ICI equalization has been addressed in the existing literature. Thus, in this paper, we propose a novel semi-blind ICI equalization scheme using the joint multiple matrix diagonalization (JMMD) algorithm to greatly reduce the intercarrier interference in OFDM. However, the well-known phase and permutation indeterminacies emerge in all blind equalization schemes. Hence we also design a few OFDM pilot blocks and propose an iterative identification method to determine the corresponding phase and permutation variants in our semi-blind scheme. Our semi-blind ICI equalization algorithm integrating the, JMMD with the additional pilot-based iterative identification is very promising for the future high-throughput OFDM systems. Through Monte Carlo simulations, the QPSK-OFDM system with our proposed semi-blind ICI equalizer can achieve significantly better performance with symbol error rate reduction in several orders-of-magnitude. For the 16QAM-OFDM system, our scheme can also improve the performance over the plain OFDM system to some extent. [ABSTRACT FROM AUTHOR]

This paper presents a new economic and effective TPEG (transport protocol experts group) application for location based service (LBS) that can be provided in terrestrial-digital multimedia broadcasting (T-DMB) transmission system. We propose a novel point-of-interest (POI) application interoperable with TPEG protocol, and introduce the POI data server/client and the DMB receiver with TPEG decoder implemented by using the proposed protocol. The stability and effectiveness of the proposed protocol is verified through the experimental broadcasting, and the pilot service using the commercial T-DMB network is being provided successfully. [ABSTRACT FROM AUTHOR]

Digital multimedia broadcasting service has been at the center of developing issues in mobile environment. in contrast to traditional multimedia broadcasting systems, mobile devices have limit of information handling capacity. In order to solve the problem, this paper presents a personalized channel recommendation system at client side in mobile environment. The system includes four modules: client manager agent, monitoring agent, data preparation agent and recommendation agent. Within the recommendation agent, we develop a recommendation algorithm using users' preference transitions for the channels. Also, we design and implement the prototype system on the Wireless Internet Platform for Interoperability. In the experiment, we compare the proposed algorithm with a conventional method. The experimental results show that the proposed recommendation system can provide better performance than the conventional method. [ABSTRACT FROM AUTHOR]

Digital video broadcasting-terrestrial (DVB-T) is an important multimedia technology capable of high data-rate transmission. Orthogonal frequency division multiplexing (OFDM) has been the backbone technique in the current DVB-T systems adopted by Europe and Japan. However, since the OFDM system is very sensitive to the frequency synchronization and phase errors, which will induce the intercarrier interference (ICI), the ongoing research has been dedicated to this ICI problem in the presence of the Doppler frequency drift and the fading channels. A means to deal with the ICI problem is called the ICI self-cancellation or polynomial cancellation coding scheme. In this paper, we establish the complete simulation environment for the physical layer of the DVB-T system and then evaluate the effectiveness of the ICI self-cancellation coding scheme compared with the existing convolutional coding scheme for different fading channels and different Doppler frequencies. According to our simulation results, we conclude that the ICI self-cancellation scheme significantly outperforms the convolutional coding scheme which is adopted by the existing DVB-T standard for the AWGN and the frequency non-selective fading channels, but both schemes have the similar performance in the frequency-selective fading channels. [ABSTRACT FROM AUTHOR]

As an effective technique for combating multipath fading and for high-bit-rate transmission over wireless channels, orthogonal frequency-division multiplexing (OFDM) is extensively used in modern digital television terrestrial broadcasting (DTTB) systems, such as the cyclic prefix OFDM (CP-OFDM) based DVB-T DTTB systems and the lime domain synchronous OFDM (TDS-OFDM) based DMB-T DTTB systems, to support high performance bandwidth-efficient multimedia services. OFDM-based DTTB systems are very sensitive to the nonlinear distortion at the transmitter and the imperfect parameters estimation at the receiver. In this paper, the combined effects of nonlinear distortion and imperfect parameters estimation on the performance of the OFDM-based DTTB systems are investigated, a closed form of symbol error probability of the OFDM-based DTTB systems with nonlinear distortion and imperfect parameters estimation is derived. Theoretical results show closely matching with those obtained by simulations for both the CPOFDM based DVB-T DTTB systems and the TDS-OFDM based DM13 T DTTB systems. [ABSTRACT FROM AUTHOR]

Although the Ungerboeck's TCM (Trellis Coded Modulation) is attractive in terms of high efficiency with low descending data rate by coding and high coding gain, it is difficult to implement To remove this complexity, a pragmatic approach to the TCM, which is realized by employing the defacto convolutional code (constraint length K= 7 and rate 1/2), was proposed. In this paper, a simpler realization of the TCM of rectangle type 2N QAM (N is even number; ≥ 4) by using the pragmatic approach is presented. We will show the convolutional coding and the Viterbi decoding by the decomposition from two-dimensions into each one-dimension independently. By this decomposing, it is possible to apply the pragmatic approach to minimize hardware and cost Therefore it is very useful for 64 QAM or 256 QAM applications such as digital video broadcasting over digital cable TV (ITU-T J.83) and Fixed Wireless Access (IEEE802.16) systems. It can be applied not only to single carrier QAM but also to multi-carrier QAM like OFDM. [ABSTRACT FROM AUTHOR]

The LInear amplification using Nonlinear Components (LINC) technique is a well-known power amplifier linearization method to reduce out-of-band interferences in a nonconstant envelope modulation system, such as Digital Video Broadcasting (DVB) system, which is based on a very sensitive to nonlinear distortions OFDM modulation scheme. The major drawback of LINC transmitters is the inherited sensitivity to gain and phase imbalances between the two amplifier branches. In this paper, a novel full-digital base band method, which corrects any gain and phase imbalances in LINC transmitters mainly due to the un-matching of the two amplifier paths, is described. Amplifiers are characterized by a level-dependent complex gain using a memoryless model. The method uses adaptive signal processing techniques to obtain the optimal complex coefficients to to direct gain and phase imbalances. Its main advantage is the ability to track the input signal variations and adapt to the changes of amplifier nonlinear characteristics. Other effects are included in the analysis such as quadrature modulator and demodulator impairments. A computer simulation has been carried out to verify method functionality. [ABSTRACT FROM AUTHOR]

MPEG-4 video streaming service is being regarded as a de facto standard service for current mobile multimedia video streaming services such as video conferencing, voice over IP, and even state-of-the-art digital multimedia broadcasting technology. There have been many illegal users who have used copyrighted material without getting permission and/or paying for its use. Therefore, much attention has been paid for Digital Rights Management (DRM) for digital media. We constructed a protection scheme for MPEG-4 video file format, which can be applied, to the video services that are exploiting the MPEG-4 standard In this protection scheme, minimum segments of every Video Object Plane in a MPEG-4 video file could be encrypted with a symmetric cryptography system like a DES (Data Encryption Standard) so that people who have not received permission and/or paid to use the contents would not be able to view them. We applied this scheme to all kinds of MPEG-4 VOP (Video Object Plane) types, that is I-, P-, and B-VOPs respectively. The prototype system was developed for proofing the feasibility of this scheme for hand-held devices and for mobile multimedia service environment. The efficiency of this scheme is reported at the end of this paper. [ABSTRACT FROM AUTHOR]

This paper introduces T-DMB transmission system in Korea based on Eureka-147 DAB and presents a new architecture of transmission system for digital multimedia services. For transmission of the digital multimedia contents in mobile environment by using the existing DAB, we developed a T-DMB processor which performs T-DMB encoding and insertion of the media stream into the existing DAB transmission system. After the implemented T-DMB processor can be connected to the front of the commercial Eureka-147 DAB system, and the performance of the T-DMB system is confirmed through the T-DMB experimental broadcasting in Korea. [ABSTRACT FROM AUTHOR]