Digital broadcasting

Abstract: Technological evolution and the ever-increasing demand for higher-quality services give broadcasters a strong incentive to completely digitize their broadcasting networks. This digitization, which is already well advanced in many program production areas and transmission links, now has to be extended to complete the last link in the broadcast chain; i.e., from broadcast transmitter to consumer receivers. It is therefore necessary to develop wholly new techniques for the broadcasting of digitally coded TV programmes. Thus an efficient baseband digital coding must be combined with a robust digital modulation and channel coding scheme that can meet the requirements of every mode of broadcast reception. This article presents the research work related to the coded orthogonal frequency division multiplex (COFDM) technology, which has now been completed in the field of digital radio (DAB), and which is under progress in the field of digital terrestrial TV. >

Abstract: To provide interactivity, a public wireless packet data network is combined with a broadband digital broadcast network. In the preferred embodiment, the broadcast network utilizes multiple transmitters at separately located sites simultaneously broadcasting the same multi-channel, multi-program signal. Broadcast waves from the transmitters propagate throughout substantially overlapping portions of the service area. Customer premises receiving systems include a receiving antenna and one or more digital entertainment terminals. The terminal includes a channel selector and digital receiver for capturing a digital transport stream from a selected channel. A processor converts selected program information from the transport stream for presentation, e.g. via a television set. The terminal also includes a CPU controlling the operation of the channel selector and the processor in response to user inputs. The CPU also communicates signaling information for interactive services via an RF packet data modem included in the terminal and the public wireless packet data network. In addition to the signaling for interactive services, the packet data network provides transport for data communications between other data devices.

Abstract: Set-top terminals utilized in broadband broadcast networks are becoming increasingly intelligent (programmable). However, transmitting executable code, data and interactive audio/video materials through a selectively dedicated link requires an extensive, broadband point-to-point broadband network, which is prohibitively expensive to implement for large numbers of customers. The present invention provides for downloading application software and transmitting audio/video information through one channel of a digital broadcast network. The network also provides two-way, low-speed data communications capacity, e.g. for signaling and/or interactive text services. Signaling via data communication with a text server controls downloading of executable code from the digital broadcast channel into a programmable digital set-top terminal. Execution of the downloaded code in turn controls selective capture and presentation of audio and video segments received over one of the digital broadcast channels. Resident operating system and application software in the terminal provides all communication with nodes of the network. The downloaded code forms a non-resident application having a set of predetermined function calls for activating communication functions of the resident software.

Abstract: This paper gives a brief review of the new Digital Video Broadcasting-Handheld(DVB-H) standard. This is based on the earlier standard DVB-T, which is used for terrestrial digital TV broadcasting. The new extension brings features that make it possible to receive digital video broadcast type services in handheld, mobile terminals. The paper discusses the key technology elements-4K mode and in-depth interleavers, time slicing and additional forward error correction-in some detail. It also gives extensive range of performance results based on laboratory measurements and real field tests. Finally it presents viewpoints relevant for DVB-H network design and system use in general.