A METHOD FOR DETERMINING ACCESS TIME OF REPEATEDLY BROADCAST OBJECTS

摘要

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. This information can be used to realize a progress indicator, so that a user can be informed about the time he has to wait for the requested object. Also, this information is essential for the realization of certain caching strategies.