Chapter: Network Concepts and Standards
Standardisation of digital television systems is formally discussed in the European Digital Video Broadcasting (DVB) Project. Many different transmission media are considered, including
The aim of the DVB Project is to arrive at standards on transmission of digital video data through the air (terrestrial), through cable and by satellite. Issues on the table are for instance modulation and channel coding, service information, multiplexing and also conditional access. The ultimate goal is to create a business environment where consumers are reasonably well protected and where various providers of services and equipment can compete on fair terms and where new businesses can enter without excessive thresholds.
The DVB Project started in 1991, when a so called Technical Module was
established. Since then, the Project has steadily grown in size; over 150
companies that wish to participate in the discussions have today signed the
Memorandum Of Understanding.
In the DVB Project, two groups focus on scrambling and conditional access. Both groups study the feasibility of a scheme where the systems share as much commonality as possible. The first, a commercially driven group called the Ad-Hoc Group on Conditional Access (Ad-Hoc group on CA), considers complete conditional access systems, including scramblers/descramblers and peripheral equipment at the transmission side. The second group, concerned with the more technical issues and called the Conditional Access Specialist Group (CASG), focusses on the decoder box and transcoding issues.
GIF Imageof DVB broadcast chain
GIF Imageof Possible scenarios for wireless (DVB satellite) transmission to cable headends
GIF Imageof essential system elements