GB2238691A

GB2238691A - Multi-party videoconferencing configuration

Info

Publication number: GB2238691A
Application number: GB8927038A
Authority: GB
Inventors: Stephen Robin Temple
Original assignee: Individual
Current assignee: Individual
Priority date: 1989-11-30
Filing date: 1989-11-30
Publication date: 1991-06-05
Also published as: GB8927038D0

Abstract

A multi-party videoconferencing configuration where each party is connected by terrestrial means through the public networks (PSTN, ISDN or leased lines) but receives the images of all the other parties directly from a geostationary satellite by means of a receive only satellite receiver. <IMAGE>

Description

MULTI-PARTY VIDEOCONFERENCING CONFIGURATION This invention relates to videoconferencing between more than two parties at geographically separated locations and which combines terrestrial and satellite transmission means into an innovative configuration.

At present videoconferencing exists between two points.

Those points can be connected by either terrestrial (coaxial, radio relay, fibre optics etc ) or by geostationary satellite means. Satellite means provides for flexible extension to twoparty to multi-party videoconferencing. This flexibility comes not only from the wide geographical area of view from a satellite but from the fact that all transmissions can be received by all parties ie the satellite is a wideband repeater.

Each party needs to have means to transmit its voice and image to the satellite, the satellite re-radiates the signals and these are received by all the other participating parties. Each party can receive the image and voice of the other party invited to talk or receive the images and voices of all the participating parties. If the user wants to display all the images of the participating parties its ground receiver must be wide enough to receive all the transmissions from the satellite.

The price for the flexibility of using satellite means is the cost of the satellite earth stations (particularly the transmitters) for each participating party and the relative inefficiency of accessing the satellite by a large number of separate parties. Further satellites are a relatively expensive means of communications over short to medium distances.

Terrestrial means of communications are more economic over short to medium distances and particularly when only two parties are involved. Extensions to multi party conferences starts to involve much complexity as each party has to be connected to all other parties. Usually all participating parties are connected to a conferencing node. The voice signals are mixed together and fed back to all participants. This is already the basis of successful multi party audio conferencing. However if users want to see the images of all the other participants the images cannot be simply mixed but must be kept separate and all of them sent back to all participants. What this means is that for each user a relatively narrow bandwidth outgoing path exists to carry the voice and image and a much wider incoming path is needed to carry the mixed voices but separate images of all the other parties.Due to the way a single local terrestrial connections is provided in the Public Switched Telephone Network (PSTN) and on the Integrated Services Digital Network (ISDN) this very much wider incoming bandwidth doesn't exist. Even with leased line connections it would be unusual for such an imbalance of capacity to be provided. It could exist by subscribing to a sufficient number of connections but most users would not carry such a high overhead for the very occasional requirements of multi-party video conferencing.

The innovative configuration, which is the subject of this claim, combines the terrestrial and satellite means of transmission to overcome the problems caused -by the way the public terrestrial connections are provided. In essence the imbalance of capacity needed to receive all the images of the other parties in multi-party videoconferencing is provided by satellite means but the outgoing connection from each party for voice and image is by terrestrial means. The mixed voice signal can be received by parties by satellite or terrestrial means.

Similarly the image of the party speaking can be provided by terrestrial or satellite means.

By means of this configuration relatively inexpensive public telecommunications network connections can be utilised by a user for videoconferencing on a two-party basis or for audio conferencing on a multi-party basis and the further facility of receiving all the other images for the occasional multi-party videoconference can be added simply and compatibly at any time by means of a satellite receive only terminal. The utility of seeing all the images of the other parties in a multi-party conference is that it adds the extra realism of seeing how other listeners are reacting to the party speaking. It also overcomes the problem of audio conferences where somebody can interrupt the person speaking and the other parties often have trouble for a while identifying who has interrupted. If this receive only terminal uses Direct Broadcasting Satellite technology the basis of such a receiver can be very inexpensive. This will make multi-party videoconferencing more accessible to a wider market.

Further the transmission from the satellite is transmitted from either one or very few points. In this way more efficient use of the satellite bandwidth is possible.

Claims

CLAIM

a. A system configuration for multi-party conferencing by telecommunications means where each party to the conference has a terrestrial connection to the public telecommunications networks (PSTN,ISDN or leased lines) for transmitting its image and sound and a receive only satellite connection for directly receiving from a geostationary satellite the images and sounds of all the other parties to that conference.

b. A system configuration for multi-party conferencing by telecommunications means where each party to the conference has a terrestrial connection to the public telecommunications networks (PSTN,ISDN or leased lines) for transmitting its image and sound and receiving the image of the party speaking and the sound of all the other parties to the conference and a receive only satellite connection for directly receiving from a geostationary satellite the images of all the other parties to that conference.

c. A system configuration for multi-party conferencing by telecommunications means where each party to the conference has a terrestrial connection to the public telecommunications networks (PSTN,ISDN or leased lines) for transmitting its image and sound and receiving the sound of all the other parties to the conference and a receive only satellite connection for directly receiving from a geostationary satellite the images of all the other parties to that conference.