Interactive video distribution systems – Video distribution system with upstream communication – Transmission network
Reexamination Certificate
1999-07-21
2001-08-07
Faile, Andrew (Department: 2611)
Interactive video distribution systems
Video distribution system with upstream communication
Transmission network
C725S121000, C725S131000, C725S111000
Reexamination Certificate
active
06272681
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to cable communication systems. More particularly, the present invention relates to high-speed transmission of data from a home or residence to a central office or cable-head end.
BACKGROUND OF THE INVENTION
Conventional cable systems can utilize a cable modem to transmit and to receive data across a coaxial cable or line. The cable couples a head end or central office to numerous pieces of video equipment disposed in a multitude of residences.
Cable systems are generally utilized as one-way systems in which cable television signals are transmitted from the head end to the video equipment coupled to the cable. The video equipment can include video cassette recorders (VCRs), television units, or other devices. The cable television signals are transmitted in a frequency range from approximately 50 megahertz (MHz) to 550 MHz. The video equipment receives the cable television signals and either provides images in accordance with the cable television signals or stores the cable television signals.
Cable modems can be utilized with existing cable systems to communicate data bidirectionally between the home and the head end. The cable modem transmits data from the home to the head end in a frequency range between approximately 5-39/42 (e.g., on a return channel). Generally, the return channel can utilize a 5-39 MHz range (low split) or a 5-42 MHz range (mid split). The cable modem receives data from the head end in a frequency range between 550-750 MHz (e.g., the downstream channel). The high-speed, downstream channel is often utilized to provide digitized services, such as, digitized entertainment to the residence, or to provide other data communications to the residence.
The return channel is typically utilized to transmit small amounts of data, such as, requests for download information, while the downstream channel is utilized to transmit large amounts of data, such as, data associated with video signals, large programs, documents, or other applications. For example, in most internet applications, larger amounts of data are requested by the residential user than by the internet source. Further, in pay-per-view movie applications, the return channel is utilized to transmit relatively small data files, including billing and addressing information, while the downstream channel is utilized to transmit the relatively large data file, including the movie.
The conventional return channel is not adequate for all cable modem applications, especially applications in which larger amounts of data must be transmitted to the head end. Heretofore, the return channel associated with conventional cable modems can be susceptible to interference from a number of other radio frequency (RF) sources, including amateur radio units and household motors, which provide distortion in the 5-39/42 MHz range. Additionally, the bandwidth associated with the conventional return channel (e.g., 5-39/42 MHz) is somewhat limited, thereby restricting the amount of data which can be sent to the head end.
Since the frequency range between 50-550 MHz is utilized by all television sets coupled to the cable, it cannot conventionally be used for return channel applications. Indeed, the reception of all television sets would be affected by any signal placed in the frequency band between 50-550 MHz. Accordingly, conventional cable modems must transmit and receive data outside of the 50-550 MHz range to protect the reception of the large number of customers who are already committed to this aspect of the cable system. Thus, data cannot normally be transmitted upstream in the 50-550 MHz frequency range because of the multi-drop nature of the cable system.
Thus, there is a need for a high-speed return channel for cable modems. Further still, there is a need for more efficient use of the frequency band between 50-550 MHz in a cable system.
SUMMARY OF THE INVENTION
The present invention relates to a transmitter for use with a cable system including a cable. The cable is coupled between the transmitter and a cable-head end. The transmitter includes a terminal and a data modulator coupled to the terminal. The data modulator provides modulated data signals in a frequency band between 50-550 MHz across the cable, wherein the modulated data signals are transmitted so as not to interfere with reception of cable television signals.
The present invention further relates to a cable modem including a receiver means and a transmitter means. The receiver means receives analog television signals in a frequency range between 50-550 MHz. The transmitter means transmits data signals on a vestigial sideband of carrier waves between the 50-550 MHz frequency range. The transmission of the data signals does not adversely affect the picture quality associated with the analog television signals.
The present invention still further relates to a transmitter for use in a cable system. The transmitter provides data signals between 50-550 MHz on a return channel to a cable-head end. The transmission of the data signals does not adversely affect the picture quality associated with analog television signals in the 50-550 MHz frequency range.
According to one exemplary aspect of the present invention, a cable modem provides data signals outside of the conventional return channel frequency range between 5-39/42 MHz. The return channel utilizes a black period associated with cable television signals or a vestigial sideband associated with cable television signals to transmit data in the 50-550 MHz frequency range. The return channel advantageously does not adversely affect the reception of cable television signals in the 50-550 MHz frequency range.
REFERENCES:
patent: 4509073 (1985-04-01), Baran et al.
patent: 5124980 (1992-06-01), Maki
patent: 5321514 (1994-06-01), Martinez
patent: 5347304 (1994-09-01), Moura et al.
patent: 5421030 (1995-05-01), Baran
patent: 5425027 (1995-06-01), Baran
patent: 5587743 (1996-12-01), Montgomery et al.
patent: 5596361 (1997-01-01), Martinez
patent: 5617148 (1997-04-01), Montgomery
patent: 5663682 (1997-09-01), Meline et al.
patent: 5666168 (1997-09-01), Montgomery et al.
patent: 5734413 (1998-03-01), Lappington et al.
patent: 5805591 (1998-09-01), Naboulsi et al.
patent: 5831679 (1998-11-01), Montgomery et al.
patent: 5870134 (1999-02-01), Laubach et al.
patent: 5986691 (1999-11-01), Henderson
patent: 6014545 (2000-01-01), Wu et al.
patent: WO 97/38529 (1997-10-01), None
Counterman, Raymond. Integrated Services to the Home and Small Business Over A Service-Independent HFC Network. Proceedings of the SPIE, Oct. 23, 1995, vol. 2609, pp. 39-49, XP-000749691.
Doshi, Bharat T. et al. A Broadband Multiple Access Protocol for STM, ATM, and Variable Length Data Services on Hybrid Fiber-Coax Networks. AT&T Technical Journal, vol. 1, No. 1, Jun. 21, 1996, Summer 1996, pp. 36-65, XP 000635761.
Harman, Dale D. et al. Local Distribution for IMTV. IEEE Multimedia, vol. 2, No. 3, Sep. 21, 1995, pp. 14-22, XP 000529089.
Conexant Systems Inc.
Faile Andrew
Foley & Lardner
Vu Ngoc
LandOfFree
Cable modem optimized for high-speed data transmission from... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Cable modem optimized for high-speed data transmission from..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cable modem optimized for high-speed data transmission from... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2462606