Hybrid multichannel data transmission system utilizing a broadcast medium

#This invention relates generally to a hybrid data transmission system, and more particularly, it relates to providing a hybrid telephone/multichannel-television (TV) and/or FM broadcast transmission system for information distribution, datacasting and interactive data communications.

#The growth and increasing popularity of the information superhighway has created a need for the transmission of high speed digital data to remote locations such as homes, offices and mobile sites. Data may consist of a variety of different types of information including for example, program files, data files, text, graphics, photographic images, audio and video clips (as distinguished from radio and TV programming).

#Standard telephone lines, cellular networks and radio systems deliver data too slowly for many of the current applications. For example, compressed still video images in a digital format requires the delivery of a large amount of data, typically 5-50 kilo bytes. Downloading a typical Internet page with multiple GIF format images, which are already compressed, can take several minutes over a standard phone line with a 14400 baud or 28800 baud modem.

#FIG. 1 is a functional block diagram of the best mode of the hybrid multichannel data transmission system utilizing a broadcast medium in accordance with the present invention.

#FIG. 2 is a functional block diagram of the head-end of the cable TV system portion of FIG. 1.

#FIG. 3 is a functional block diagram of one of the clients shown in FIG. 1.

#The present invention employs a multichannel data transmission system that provides access to remote systems: the Internet, commercial on-line services, enterprise networks, common carrier networks and the like.

#In the preferred embodiment using the Internet as an example, a client, such as a computer, terminal, set-top box device and the like, utilizes a triangular communications link. One of the links in the triangle is the traditional dial-up Internet communications link, telephone modems coupled point to point by a public switched telephone network (PSTN) with a relatively limited available bandwidth for data transmission. The client is linked to the router of an Internet service provider (ISP). Alternatively, if available, the upstream channel on a cable TV system can be used in place of the PSTN for purposes of an upstream channel. Another of the links in the triangle is a higher-speed broadcast link that is not traditionally used for data transmission. In the preferred embodiment this broadcast link is the cable TV broadcast from the cable TV system head-end to the cable TV subscribers which provides high data throughput. To complete the triangle, these two links are combined with a third high speed link between the router and the distributor at the cable TV system head-end.

#Additionally, at the client is a modified television or radio receiver (implemented as a board in or attached to a computer or set-top box). At the cable TV system head-end a distributor controls a modified television or radio transmitter which can transmit data either on a full TV channel 6 Mhz RF modem, a partial TV channel (less than 6 Mhz bandwidth) RF modem, an FM radio data broadcast channel, or as a simultaneous data signal inserted in the raster scan lines of a normal television signal; either in the vertical blanking interval (VBI), or by using a data subcarrier or by other multiplexing means. Each client receiver is equipped with one or more tuners so that it can simultaneously receive data over one or several channels. The objective is to speed data transmission while making the hybrid data path transparent to the end-user.