Showing papers on "Broadcasting published in 2002"
TL;DR: This paper proposes to significantly reduce or eliminate the communication overhead of a broadcasting task by applying the concept of localized dominating sets, which do not require any communication overhead in addition to maintaining positions of neighboring nodes.
Abstract: In a multihop wireless network, each node has a transmission radius and is able to send a message to all of its neighbors that are located within the radius. In a broadcasting task, a source node sends the same message to all the nodes in the network. In this paper, we propose to significantly reduce or eliminate the communication overhead of a broadcasting task by applying the concept of localized dominating sets. Their maintenance does not require any communication overhead in addition to maintaining positions of neighboring nodes. Retransmissions by only internal nodes in a dominating set is sufficient for reliable broadcasting. Existing dominating sets are improved by using node degrees instead of their ids as primary keys. We also propose to eliminate neighbors that already received the message and rebroadcast only if the list of neighbors that might need the message is nonempty. A retransmission after negative acknowledgements scheme is also described. The important features of the proposed algorithms are their reliability (reaching all nodes in the absence of message collisions), significant rebroadcast savings, and their localized and parameterless behavior. The reduction in communication overhead for the broadcasting task is measured experimentally. Dominating set based broadcasting, enhanced by a neighbor elimination scheme and highest degree key, provides reliable broadcast with /spl les/53 percent of node retransmissions (on random unit graphs with 100 nodes) for all average degrees d. Critical d is around 4, with <48 percent for /spl les/3, /spl les/40 percent for d/spl ges/10, and /spl les/20 percent for d/spl ges/25. The proposed methods are better than existing ones in all considered aspects: reliability, rebroadcast savings, and maintenance communication overhead. In particular, the cluster structure is inefficient for broadcasting because of considerable communication overhead for maintaining the structure and is also inferior in terms of rebroadcast savings.
999 citations
23 Sep 2002
TL;DR: A new heuristic is described, Embedded Wireless Multicast Advantage, that compares well with other proposals and is explained how it can be distributed, and a formal proof that the problem of power-optimal broadcast is NP-complete is provided.
Abstract: In all-wireless networks a crucial problem is to minimize energy consumption, as in most cases the nodes are battery-operated. We focus on the problem of power-optimal broadcast, for which it is well known that the broadcast nature of the radio transmission can be exploited to optimize energy consumption. Several authors have conjectured that the problem of power-optimal broadcast is NP-complete. We provide here a formal proof, both for the general case and for the geometric one; in the former case, the network topology is represented by a generic graph with arbitrary weights, whereas in the latter a Euclidean distance is considered. We then describe a new heuristic, Embedded Wireless Multicast Advantage. We show that it compares well with other proposals and we explain how it can be distributed.
541 citations
TL;DR: In this article, the authors developed different modeling ideas for each of the features of the problem, such as the handling of interference among radio signals, the availability of frequencies, and the optimization criterion.
Abstract: Wireless communication is used in many different situations such as mobile telephony, radio and TV broadcasting, satellite communication, wireless LANs, and military operations. In each of these situations a frequency assignment problem arises with application specific characteristics. Researchers have developed different modeling ideas for each of the features of the problem, such as the handling of interference among radio signals, the availability of frequencies, and the optimization criterion.
386 citations
Patent•
30 Dec 2002
TL;DR: In this paper, the authors proposed a one- or two-way Direct-To-Home (DTH) satellite communications system which broadcast high bit rate wideband television and multimedia content to user terminals located within a desired coverage area and, more specifically, a single or multi-transponder Direct-to-Home satellite communication system in which a high bit-rate wideband data stream is comprised of real-time, statistically multiplexed information and non-real-time information that is transmitted to a subscriber media gateway device for storage and later use.
Abstract: The present invention relates to one- or two-way Direct-To-Home (DTH) satellite communications systems which broadcast high bit rate wideband television and multimedia content to user terminals located within a desired coverage area and, more specifically, a single or multi-transponder Direct-To-Home satellite communications system in which a high bit rate wideband data stream is comprised of real-time, statistically multiplexed information and non-real-time information that is transmitted to a subscriber media gateway device for storage and later-use. The user terminal contains a specially designed receiving system and may contain a transmitter for transmission of a return data channel to the Broadcast Center.
196 citations
Patent•
4 Oct 2002
TL;DR: In this paper, a multiple channel architecture is designed to allow targeted advertising directed to television terminals connected to an operations center or a cable head end, where advertisements may be broadcast on the same channel as the television program and feeder channels may carry alternate advertising that may be better suited for certain viewing audiences.
Abstract: A novel multiple channel architecture is designed to allow targeted advertising directed to television terminals connected to an operations center or a cable headend. Advertisements are displayed during commercial breaks in the television programs. Such advertisements may be broadcast on the same channel as the television program. In addition, feeder channels may carry alternate advertising that may be better suited for certain viewing audiences. The operations center or the cable headend generate a group assignment plan that assigns the television terminals to groups, based on factors such as area of dominant influence, household income and other demographic data, and programs watched data gathered by the television terminals. A switching plan is then generated that instructs the television terminals to remain with the program channel or to switch to one of the alternate feeder channels during the program breaks. The television terminals record which channels were viewed during the program breaks, and report this information to the cable headends and the operations center. The reported information is used to generate billing for commercial advertisers, and to analyze viewer watching habits. The invention uses upstream data reception hardware, databases and processing hardware and software to accomplish these functions.
167 citations
Patent•
10 Sep 2002
TL;DR: In this paper, the authors proposed to use a broadcasting antenna in a first underground location and then to insert another underground antenna at a geographic point where services are desired, to reach a large number of remote sites without undertaking the expense associated with providing direct high-speed fiber optic, cable, or wireline connections to those sites.
Abstract: High bandwidth services provided in the core of the network may be extended to the network edge by utilizing one or more underground wireless communications links. The underground communications link may be formed by burying a broadcasting antenna in a first underground location and then burying another underground antenna at a geographic point where services are desired. By transmitting the signals underground, it is possible to reach a large number of remote sites without undertaking the expense associated with providing direct high-speed fiber optic, cable, or wireline connections to those sites. Additionally, since the transmission is underground, the wireless communications may be provided in a portion of the spectrum otherwise licensed for use aboveground. This reuse of spectrum in a different transmission medium results in a large increase in the amount of data that may be transmitted over the existing allocated wireless spectrum.
159 citations
TL;DR: This paper shows how to minimize the average response time given multiple broadcast channels by optimally partitioning data among them and offers an approximation algorithm that is less complex than the optimal and shows that its performance is near-optimal for a wide range of parameters.
Abstract: Broadcast is a scalable way of disseminating data because broadcasting an item satisfies all outstanding client requests for it. However, because the transmission medium is shared, individual requests may have high response times. In this paper, we show how to minimize the average response time given multiple broadcast channels by optimally partitioning data among them. We also offer an approximation algorithm that is less complex than the optimal and show that its performance is near-optimal for a wide range of parameters. Finally, we briefly discuss the extensibility of our work with two simple, yet seldom researched extensions, namely, handling varying sized items and generating single channel schedules.
140 citations
TL;DR: In this article, a recursive frequency splitting (RFS) scheme was proposed to reduce the waiting time of new viewers by having new viewers wait no longer than /spl Theta/(D/2/sup k/2)/D/5/sup K/2 ), where K is the length of the video.
Abstract: One way to broadcast a popular/hot video is to let multiple users share a few channels. The stress on the scarce channels can be alleviated without sacrificing viewer waiting time. One common approach is to partition the video into fixed-length segments, which are broadcast on several channels periodically. Two representative approaches are the fast broadcasting scheme and the PAGODA scheme, which can broadcast a video using k channels by having new viewers wait no longer than /spl Theta/(D/2/sup k/) and /spl Theta/(D/5/sup k/2/) time, respectively, where D is the length of the video. In this paper, we propose a new scheme, called recursive frequency splitting (RFS), that significantly improves on existing schemes in terms of viewer waiting time. Some lower bounds on the viewers' waiting time are also developed.
122 citations
Patent•
2 Aug 2002
TL;DR: An apparatus and method for providing broadcasting service in a mobile communication system is described in this paper. But it does not specify a broadcast protocol for the transmission of video data from a video resource to a mobile station.
Abstract: An apparatus and method for providing broadcasting service in a mobile communication system. A format converter transcodes video data received from video resources to a format suitable for the mobile communication system. A base station spreads the transcoded video data with a predetermined dedicated spreading code and broadcasts the spread video signal. A mobile station receives and despreads the broadcasting signal from the base station with the spreading code.
108 citations
Patent•
2 May 2002TL;DR: In this article, a first signal containing desired data may be received by a receiving device at a user location, wherein the first signal is broadcast from a first transmitting station associated with a first broadcast coverage.
Abstract: Methods and systems for seamlessly broadcasting data to a user moving among a plurality of broadcast coverage areas. A first signal containing desired data may be received by a receiving device at a user location, wherein the first signal is broadcast from a first transmitting station associated with a first broadcast coverage. Thereafter, the receiving device (e.g., a radio or in-vehicle television) can be automatically instructed to search for and tune to a second transmitting station associated with a second broadcast coverage area broadcasting a second signal containing the desired data if the first signal fades at the user location, thereby permitting the user to seamlessly receive data as the user moves among a plurality of broadcast coverage areas. The receiving device can also be automatically instructed to search for and tune to a third transmitting station broadcasting a third signal containing data of a type associated with the desired data, if the second signal containing the desired program cannot be identified.
86 citations
TL;DR: Colin Fraser and Sonia Restrepo-Estrada illustrate the role of a radio station in providing the forum for the participatory, public dialogue which is essential for social change.
Abstract: Colin Fraser and Sonia Restrepo-Estrada illustrate the role of a radio station, owned and run by a community, in providing the forum for the participatory, public dialogue which is essential for social change. The radio station is a platform for identifying and analysing problems and their solutions, thereby determining development inputs that truly meet local needs. Open access to on-air complaints from the audience can pressure local authorities to adopt practices of good governance and transparency. Cheap and easy to install and operate, community radio can also be the interface between poor communities and the Internet.
16 Nov 2002
TL;DR: An algorithm that broadcasts in logarithmic time on all graphs from the work of Bar-Yehuda et al. is constructed, giving the first correct proof of an exponential gap between determinism and randomization in the time of radio broadcasting.
Abstract: In a seminal paper, Bar-Yehuda et al. (1992) considered broadcasting in radio networks whose nodes know only their own label and labels of their neighbors. They claimed a linear lower bound on the time of deterministic broadcasting in such radio networks, by constructing a class of graphs of diameter 3, with the property that every broadcasting algorithm requires linear time on one of these graphs. Due to a subtle error in the argument, this result is incorrect. We construct an algorithm that broadcasts in logarithmic time on all graphs from the work of Bar-Yehuda et al. Moreover, we show how to broadcast in sublinear time on all n-node graphs of diameter o(log log n). On the other hand, we construct a class of graphs of diameter 4, such that every broadcasting algorithm requires time /spl Omega/(4/spl radic/n) on one of these graphs. In view of the randomized algorithm, running in expected time O(D log n + log/sup 2/ n) on all n-node graphs of diameter D, our lower bound gives the first correct proof of an exponential gap between determinism and randomization in the time of radio broadcasting.
15 Aug 2002
TL;DR: An O(N log3N)- time randomized algorithm for gossiping in radio networks with unknown topology is given, an improvement over the fastest previously known algorithm that works in time O( N log4 N).
Abstract: This paper has two parts. In the first part we give an alternative (and much simpler) proof for the best known lower bound of ?(Dlog (N/D)) time-steps for randomized broadcasting in radio networks with unknown topology. In the second part we give an O(N log3N)- time randomized algorithm for gossiping in such radio networks. This is an improvement over the fastest previously known algorithm that works in time O(N log4 N).
TL;DR: Tests performed by the Communications Research Center Canada to investigate the on-channel repeater (OCR) for digital television broadcasting services using the ATSC-8VSB transmission standard find the areas where the coverage of the OCR overlaps with the main transmitter.
Abstract: This paper presents the results of tests performed by the Communications Research Center Canada (CRC) to investigate the on-channel repeater (OCR) for digital television broadcasting services using the ATSC-8VSB transmission standard. The focus has been to study the areas where the coverage of the OCR overlaps with the main transmitter. The factors involved in successful reception in these areas and their impact on the design and configuration of this kind of repeater are identified and discussed.
Patent•
25 Mar 2002
TL;DR: In this paper, a method for broadcasting streaming video according to the present invention has the steps of receiving a plurality of video input streams, each of the plurality of videos being transmitted via an IP-based network, selecting one of the video inputs for broadcast as a video output stream, and broadcasting the video output streams.
Abstract: Method and apparatus for broadcasting streaming video. A method for broadcasting streaming video according to the present invention has the steps of receiving a plurality of video input streams, each of the plurality of video input streams being transmitted via an IP-based network, selecting one of the plurality of video input streams for broadcast as a video output stream, and broadcasting the video output stream. The invention provides a technique by which any of a plurality of video input streams transmitted via the Internet or other IP-based network can be selectively broadcast in real time, and in which switching among the plurality of video input streams can be conducted in real time. The video output stream can also be broadcast over the Internet or other IP-based network such that a viewer can receive the various broadcasts on a PC or other device without re-connecting for each broadcast.
7 Aug 2002
TL;DR: This work proposes an alternate search based paradigm wherein minimum-cost trees in wireless networks are found through a search process, and two computationally efficient procedures for checking the feasibility (viability) of a solution in the search space are presented.
Abstract: Wireless multicast/broadcast sessions, unlike wired networks, inherently reach several nodes with a single transmission. For omnidirectional wireless broadcast to a node, all nodes closer will also be reached. An algorithm for constructing the minimum power tree in wireless networks was first proposed by Wieselthier et al. (2000). The broadcast incremental power (BIP) algorithm suggested by them is a "node-based" minimum-cost tree algorithm for wireless networks. We propose an alternate search based paradigm wherein minimum-cost trees in wireless networks are found through a search process. Two computationally efficient procedures for checking the feasibility (viability) of a solution in the search space are presented. A straightforward procedure for initializing the search using stochastically generated trees is also proposed.
AT&T1
TL;DR: Very high variability in terms of the traffic volume with an order of magnitude or more increase in the offered load over tens of minutes is found, suggesting the potential benefit of a shared infrastructure that can exploit statistical multiplexing.
Abstract: The emergence of the Internet as a pervasive communication medium, and the widespread availability of digital video technology have led to the rise of several networked streaming media applications such as live video broadcasts, distance education and corporate telecasts. This paper studies the traffic associated with two major categories of streaming content on-demand streaming of pre-recorded content and live broadcasting. Using streaming logs from a commercial service, we analyze the traffic along a number of dimensions such as session characterization, object popularity, protocol choice and network load. Among our findings, (i) high bandwidth encodings account for about twice as many requests as low bandwidth ones, and make up about 94% of the traffic, (ii) Windows Media streams account for more than 75% of all requests, when the content is available in both Windows and Real formats, (iii) TCP based transport protocols dominate over UDP being used in about 70% of all bytes transfered (iv) Object popularities exhibit substantial skew with a few objects accounting for most of the load, (v) A small percentage of IP addresses (or routing prefixes or origin autonomous systems (ASes)) account for most of the traffic demand across a range of performance metrics. This last behavior suggests that substantial bandwidth efficiency can be realized with a distribution infrastructure comprised of a relatively small number of replicas, placed close to the heavy-hitter ASes. We also found very high variability in terms of the traffic volume with an order of magnitude or more increase in the offered load over tens of minutes, suggesting the potential benefit of a shared infrastructure that can exploit statistical multiplexing.
18 Nov 2002
TL;DR: This paper presents an approach to secure broadcasting of web documents, based on the use of encryption techniques, and supporting the specification of fine-grained temporal access control policies, to generate a unique encrypted copy of the document to be released.
Abstract: Secure broadcasting of web documents is becoming a crucial need for many web-based applications. Under the broadcast document dissemination strategy a web document source periodically broad-casts (portions of) its documents to a possibly large community of subjects, without the need of explicit subject requests. By secure broadcasting we mean that the delivery of information to sub-jects must obey the access control policies of the document source. Since different subjects may have the right to access different portions of the same document, enforcing secure broadcasting requires to efficiently manage a large number of different physical views of the requested document and sending them to the proper subjects. In this paper we present an approach to secure broadcasting of web documents, based on the use of encryption techniques, and supporting the specification of fine-grained temporal access control policies. The idea is to generate a unique encrypted copy of the document to be released, where different portions of the docu-ment are encrypted with different keys, on the basis of the specified access control policies. Each subject then obtains the secret keys corresponding to document portions he/she is authorized to access. The key aspect of our approach is that the number of keys to be generated does not depend on the number of subjects nor on the document dimension, but only on the number of specified access control policies and the associated temporal constraints.
TL;DR: In this paper, the first polynomial-time approximation scheme for data broadcast with O(1) channels and when each message has arbitrary probability, unit length and bounded cost was presented.
Abstract: The data broadcast problem is to find a schedule for broadcasting a given set of messages over multiple channels. The goal is to minimize the cost of the broadcast plus the expected response time to clients who periodically and probabilistically tune in to wait for particular messages.
The problem models disseminating data to clients in asymmetric communication environments, where there is a much larger capacity from the information source to the clients than in the reverse direction. Examples include satellites, cable TV, internet broadcast, and mobile phones. Such environments favor the ``push-based'' model where the server broadcasts (pushes) its information on the communication medium and multiple clients simultaneously retrieve the specific information of individual interest.
This paper presents the first polynomial-time approximation scheme (PTAS) for data broadcast with O(1) channels and when each message has arbitrary probability, unit length and bounded cost. The best previous polynomial-time approximation algorithm for this case has a performance ratio of 9/8.
7 Nov 2002
TL;DR: This paper outlines the technical development of the terrestrial wireless and satellite audio broadcasting systems in the U.S., providing details on specific source and channel coding designs and adding perspective on why specific designs were selected in the final systems.
Abstract: The move to digital is a natural progression taking place in all aspects of broadcast media applications from document processing in newspapers to video processing in television distribution. This is no less true for audio broadcasting which has taken a unique development path in the United States. This path has been heavily influenced by a combination of regulatory and migratory requirements specific to the U.S. market. In addition, competition between proposed terrestrial and satellite systems combined with increasing consumer expectations have set ambitious, and often changing, requirements for the systems. The result has been a unique set of evolving requirements on source coding, channel coding, and modulation technologies to make these systems a reality. This paper outlines the technical development of the terrestrial wireless and satellite audio broadcasting systems in the U.S., providing details on specific source and channel coding designs and adding perspective on why specific designs were selected in the final systems. These systems are also compared to other systems such as Eureka-147, DRM, and Worldspace, developed under different requirements.
TL;DR: Performance results show that the overhead of supporting multiple versions can be kept low while providing a considerable increase in concurrency, and multiversion broadcast provides clients with the possibility of accessing multiple server states in a single broadcast cycle.
Abstract: Recently, broadcasting has attracted considerable attention as a means of disseminating information to large client populations in both wired and wireless settings. In this paper, we consider broadcasting multiple versions of data items to increase the concurrency of client transactions in the presence of updates. We introduce various techniques for organizing multiple versions on the broadcast channel. Performance results show that the overhead of supporting multiple versions can be kept low while providing a considerable increase in concurrency. Besides increasing the concurrency of client transactions, multiversion broadcast provides clients with the possibility of accessing multiple server states in a single broadcast cycle. Furthermore, multiversioning increases the tolerance of client transactions of disconnections from the broadcast channel.
TL;DR: In this paper, the authors examine the construction of public identities in ''lifestyle' television programming, specifically property shows, in which members of the public appear either as potential home buyers (house-hunters') or as home owners looking to maximize the value of their properties (vendors).
Abstract: The participation of members of the public in the mass media has been studied discursively at the level of live broadcasting, notably in talk radio and talk shows on television. In this article I examine the construction of public identities in `lifestyle' television programming, specifically property shows, in which members of the public appear either as potential home buyers (`house-hunters') or as home owners looking to maximize the value of their properties (`vendors'). In a selected episode of the Channel 5 show Hot Property, I explore the way in which these identities are managed within the text, through an eclectic analysis both of broad sociocultural discourses and of the verbal and physical interaction between the host and the public participants. It is sometimes argued that media exposure can be empowering for the general public, but in a tightly edited production such as this, subject positions are created for participants that may be less than flattering.
TL;DR: This work proposes two methods aiming to reduce client access latency of broadcast data based on analyzing the broadcast history using data mining techniques and focuses on improving the cache hit ratio to be able to decrease the access latency.
Abstract: Mobile computers can be equipped with wireless communication devices that enable users to access data services from any location. In wireless communication, the server-to-client (downlink) communication bandwidth is much higher than the client-to-server (uplink) communication bandwidth. This asymmetry makes the dissemination of data to client machines a desirable approach. However, dissemination of data by broadcasting may induce high access latency in case the number of broadcast data items is large. We propose two methods aiming to reduce client access latency of broadcast data. Our methods are based on analyzing the broadcast history (i.e., the chronological sequence of items that have been requested by clients) using data mining techniques. With the first method, the data items in the broadcast disk are organized in such a way that the items requested subsequently are placed close to each other. The second method focuses on improving the cache hit ratio to be able to decrease the access latency. It enables clients to prefetch the data from the broadcast disk based on the rules extracted from previous data request patterns. The proposed methods are implemented on a Web log to estimate their effectiveness. It is shown through performance experiments that the proposed rule-based methods are effective in improving the system performance in terms of the average latency as well as the cache hit ratio of mobile clients.
TL;DR: In this paper, the authors identify key programming practices that programmers use to manage their stations' music formats and present a typology of repertoires of such practices, and discuss the implications of each programming repertoire for stations' programming formats and the structural conditions that promote the use of programming repertoire.
Abstract: How do radio stations decide what music to play on the air? Previous studies offer a single answer to this question. In contrast, this study examines the variety of ways that radio programmers answer this question by conceptualizing them as mediators between record companies and radio audiences. From interviews with programmers at commercial radio stations in the United States we identify key programming practices that programmers use to manage their stations' music formats and present a typology of repertoires of such practices. We then discuss the implications of each programming repertoire for stations' music formats and the structural conditions that promote the use of each programming repertoire. In conclusion, we consider the study's implications for understanding culture production in the commercial radio industry.
TL;DR: In this article, the authors evaluate the evolution of community radio in postapartheid South Africa where a three-tier broadcasting system has replaced the monopoly of a state-run behemoth, the South African Broadcasting Corporation.
Abstract: This paper evaluates the evolution of community radio in postapartheid South Africa where a three-tier broadcasting system—public, commercial, and community—has replaced the monopoly of a state-run behemoth, the South African Broadcasting Corporation. The paper commences with an overview of South Africa's institutionalized culture of exclusion in the broadcasting sector and in other social spheres. A conceptual review of participatory communication precedes and provides foundation for the examination of the operations of two community radio stations located in two of South Africa's previously marginalized and disenfranchised communities. Although South Africa's adoption of community radio answers perpetual questions about the sustenance of community radio, the ongoing experience poses a few challenges.
Patent•
30 Sep 2002TL;DR: In this paper, the authors present a digital mobile terminal system for accessing mobile internet services including a VHF/AM/FM radio receiver and a subsystem that handles interfaces and interactions between the mobile terminal and a radio network via a digital data stream.
Abstract: The present invention comprises a digital mobile terminal system for accessing mobile internet services including a VHF/ AM/FM radio receiver and a subsystem that handles interfaces and interactions between the digital mobile terminal (110) and a radio network via a digital data stream, interfaces and interactions between the digital mobile terminal and a mobile internet services platform (225) and interfaces and interactions between the digital mobile terminal and a user seeking an access and interact with mobile internet services. The present invention also comprises a radio broadcasting server platform (220) for transmitting an RDS data stream including a subsystem that handles interfaces and interaction between the radio broadcasting server platform and a radio network via the digital data stream and interfaces and interactions between the radio broadcasting server platform and a mobile internet services platform. The present invention further comprises a method for operating the digital mobile terminal for accessing mobile internet services and a method for operating a radio broadcasting server platform for transmitting an RDS data stream (400).
Patent•
23 Apr 2002
TL;DR: In this article, a method for digital data distribution or broadcasting that takes advantage of non-deterministic (or "opportunistic") unused bandwidth in dynamically optimized broadband digital broadcast systems is presented.
Abstract: A method for digital data distribution or broadcasting that takes advantage of non-deterministic (or 'opportunistic') unused bandwidth in dynamically optimized broadband digital broadcast systems. Digital data files received from broadcasts are stored in mass storage devices for viewing at a later time at high speed, overcoming 'last mile' narrow bandwidth issues. Instead of reserving a particular communications channel or data transfer spectrum, data is opportunistically 'piggybacked' onto unrelated broadcasts, using otherwise unused bandwidth within existing broadcast channels or spectrums. The broadcast source does not target the digital files at specific identifiable users or broadcast contents based on their interactive requests. Data broadcasting in accordance with the present invention may be implemented to work with any medium which allows the delivery of large files in a one-to-many fashion (i.e., 'broadband broadcast medium'), such as digital cable, digital broadcast satellite, terrestrial digital television, and computer networks that are broadcast-enabled and sufficiently broadband.
Patent•
TL;DR: In this article, the assignment and validation information originating with an IP address server is broadcast only to those mobile terminals awaiting assignment or validation information using a local broadcast IP address, and the validation and assignment is automatically begun once a mobile terminal enters a new subnet by resetting the mobile terminal's IP address to the broadcast address for assignment, and then broadcasting validation and, if necessary, assignment requests to the wireless IP network.
Abstract: The transmission of unnecessary assignment and validation information to mobile terminals in wireless IP networks is automatically blocked. Assignment and validation information originating with a mobile terminal is discarded by a base station if the information is not directly received by the base station from a mobile terminal. Assignment and validation information originating with an IP address server is broadcast only to those mobile terminals awaiting assignment or validation information using a local broadcast IP address. The validation and assignment is automatically begun once a mobile terminal enters a new subnet by resetting the mobile terminal's IP address to the broadcast address for assignment and validation requests and then broadcasting validation and, if necessary, assignment requests to the wireless IP network.
TL;DR: This work analyzes the conditions necessary to provide VCR functions in NVoD and proposes a reception schedule that satisfies these conditions, with minimal resource requirements, and demonstrates, by simulation, that the scheme provides VCR functionality consistently with minimal buffer space.
Abstract: A true video-on-demand (TVoD) system allows users to view any video program, at any time, and perform any VCR function, but its per-user video delivery cost is very expensive. A near video-on-demand (NVoD) system uses a more scalable approach by batching multiple clients to a shared stream of broadcasting videos. Staggered video broadcasting, one of the NVoD techniques, broadcasts multiple streams of the same video at staggered times, with one stream serving multiple clients. In order to provide subscribers with a high-quality VoD service, it is desirable to add VCR functionality, such as fast forward and fast rewind, but it is not easy to provide VCR functionality in NVoD, especially a video broadcasting system where no dedicated or interactive channel is available. We analyze the conditions necessary to provide VCR functions and then propose a reception schedule that satisfies these conditions, with minimal resource requirements. Since our proposed scheme receives video frames as units, it can rapidly sustain a changing VCR action pattern. It is demonstrated, by simulation, that the scheme provides VCR functionality consistently with minimal buffer space.
21 Nov 2002
TL;DR: The first logarithmic approximation algorithm for the Minimum Energy Consumption Broadcast Subgraph (MECBS) problem is presented, which uses an interesting reduction to Node-Weighted Connected Dominating Set.
Abstract: Motivated by the problem of supporting energy-efficient broadcasting in ad hoc wireless networks, we study the Minimum Energy Consumption Broadcast Subgraph (MECBS) problem. We present the first logarithmic approximation algorithm for the problem which uses an interesting reduction to Node-Weighted Connected Dominating Set. We also show that an important special instance of the problem can be solved in polynomial time, solving an open problem of Clementi et al. [2].