Abstract: Broadcast based information systems like Teletext use a unidirectional communication scheme in order to get access to information. This means that requests for data objects are not transmitted from a client to a server. Instead the receiver part of the client has to listen for the requested object on the broadcast medium and copy it to the local storage when it goes by. The access time from the receiver point of view is defined as the difference between the reception point in time of the object and the point in time when the request was made. Nowadays realized broadcast based information systems are not able to determine precisely when a requested object will be available. The present invention uses a repetition distance which defines an additional parameter which has to be transmitted with each broadcast data object at the transmitter side. The receiver can use this information to determine the precise repetition point in time of a requested object.

Abstract: A generic information service structure is assumed and a method to transmit the information service from a server side to an unlimited number of users over a broadcast medium is provided. This transmission method comprises the following steps:—performing a fragmentation within each of categories representing said information service to create data fragments,—adding signalling information to every data fragment, which signalling information allows a consistent reassembly of said data fragments at a receiver on basis of predefined protocol rules, to create respective broadcast objects, and—transmitting said broadcast objects in an order according to an information content of said data fragment within said broadcast object. Preferrably, said fragmentation is performed dependent on the information content of the data to be transmitted.