An asymmetric communication protocol providing semi-reliable transmission with improved availability. Messages are provided to a scheduling sender which repeatedly rebroadcasts the data for a specified time period. Multiple messages are arranged in a data carousel with each message transmitted on each revolution of the carousel. Messages are removed as they become obsolete. Clients joining the broadcast late continue to have access to data on the carousel.

A digital signal receiver includes a distributed information storage unit having a data storage device for storing broadcast information. A menu frame for the information items stored in the data storage device is reformed as table-of-contents information having the same signal format as the received broadcast signal. As a result, it is unnecessary to specially provide a browser for creating a display frame, simplifying the structure of the receiver as a whole.

A broadcast apparatus broadcasts broadcast data. In the broadcast apparatus, an acquiring unit acquires broadcast data and a reproduction time period in which the broadcast data is to be reproduced by a reception apparatus, and a broadcasting unit repeatedly broadcasts the broadcast data from a predetermined time period before a start of the reproduction time period to an end of the reproduction time period.

An image information distribution system is provided for distributing image information via a communication network to subscribers. When a subscriber changes an image information specification channel, the system changes the channel at high speed, shortening the image information wait time. An image information distribution system is also provided for offering a video on demand service. Thus, in the image information distribution system, in addition to image information requested by a subscriber, other image information is also provided for a subscriber accommodation node according to a predetermined image information selection rule. The node includes means for extracting the image information requested by the subscriber from a plurality of provided image information entries, and providing it to the subscriber. When the subscriber requests change of the image information, setting of the image information extraction means is changed and new image information is extracted from the provided image information entries and provided to the subscriber. The node contains a memory for temporarily storing image information corresponding to each subscriber and a controller for controlling read of the memory. Image information is stored in the memory in response to a subscriber's request, and the controller then provides the stored information to the subscriber by controlling read of the memory according to the subscriber's request, such as reproduction, stop, making still, skip, or retrieval.

An apparatus and method for broadcast burst transmission of compressed audio/video programs from a stored library to a multiplicity of subscribers. The stored programs are burst transmitted repeatedly in a predetermined sequence of entire programs or segments thereof to a receiver at each subscriber's location. Each receiver is operative for accessing the predetermined broadcast schedule, Inputting a subscriber's order for one or more programs, monitoring the broadcast burst transmissions for the one or more ordered programs, receiving the one or more ordered programs in a burst time period corresponding to the time period of the burst transmission, and storing the one or more ordered programs. The subscriber then enjoys full VCR-like control over playback at his convenience of the ordered, stored programs, that are then decompressed by the receiver for viewing in real time.