Telecommunications – Radiotelephone system
Reexamination Certificate
1998-04-20
2001-04-17
Tsang, Fan (Department: 2746)
Telecommunications
Radiotelephone system
C455S001000, C455S001000, C348S478000, C348S014160, C348S014160, C348S460000, C348S461000, C348S467000, C348S476000
Reexamination Certificate
active
06219537
ABSTRACT:
FIELD OF THE INVENTION
The present invention pertains to the field of television communication systems and, more particularly, the present invention relates to a system and method of transmitting digital data information in the Vertical Blanking Interval (VBI) for transmission in a wireless communication network.
BACKGROUND OF THE INVENTION
Personal Communication Services (“PCS”) describes systems and services which enable a user to communicate anytime, anywhere, and in any form. The basic structure is to allocate a single ID called a Universal Personal Telecommunication (UPT) number to a device allowing voice and data communication of any kind, any time, and anywhere in the world. Because PCS is digital, it can handle data, messaging, paging, and in the future, full multimedia access—besides regular voice telephony—all with one device and one UPT.
A PCS communications system is disclosed in U.S. Pat. No. 5,481,546 to Dinkins. The Dinkins patent discloses an interactive nationwide data service communication system for stationary and mobile battery operated subscriber units that transmit digital communications in the milliwatt power range and contemplates utilization of VBI to send messages; however, the Dinkins system contemplates a plurality of receive-only base stations and local base station repeater cell means distributed throughout the designated area for relaying the low power digital messages within the network. Similarly, a system and method for providing microcellular PCS utilizing embedded switches is disclosed in U.S. Pat. No. 5,457,736 to Cain et al. The system, however, uses existing wireline switches to establish communications between the mobile terminals and an Advanced Intelligent Network. An asymmetric hybrid access system and method is disclosed in U.S. Pat. No. 5,586,121 to Maura et al. The system can utilize communication media to distribute to remote clients high speed data packets on a downstream channel and to transmit return data along an independent upstream channel at a lower speed than the data packet rate transmitted in the downstream channel. The communication media for each of the upstream and downstream channels is selected from one of a CATV distribution network, a cell site, a television transmitter station, a fiber optic network, a wireless network, a telephone network or a satellite communication network. The system is limited in providing full-duplex interactive asymmetric communications between the host server and a plurality of downstream clients using independent upstream channels. However, the known PCS systems do not disclose the concept of utilizing the existing VBI band width for voice (fixed or mobile) along with the technology for return signal processing and signal finessing of the present invention.
Additionally, the enhanced PCS system of the present invention features the receiving of the messaging or PCS information on the VBI carrier by a mobile transceiver, which can retransmit the PCS or return data information on the same carrier to the return signal processor. Finally, the enhanced PCS system of the present invention also features acquiring of the return signal having such message and PCS information on the carrier by the return signal processor, whereby such features are performed at low power and are not disclosed in the prior art.
Additional existing TV data broadcasting communication systems can utilize either the horizontal blanking interval (“HBI”) or the vertical blanking interval (“VBI”) of the TV signal to deliver point-to-multipoint data delivery, for example, when information is being transmitted simultaneously to many locations. VBI data broadcasting can deliver data simultaneously and at high speed to anyone who needs such information as news, stock quotes, weather radar images, road and traffic conditions and closed captioned text. A standard North American television signal consists of 525 horizontal lines divided into two fields each with 262.5 lines. The first 21 lines of each field comprise the Vertical Blanking Interval (“VBI”); lines
1
to
9
of the VBI are for timing and sequencing; lines
10
through
21
are not allocated, however, line
21
typically has been used to deliver closed caption information to the hearing impaired (via a decoder unit) everywhere the television signal can be received. Therefore, VBI broadcasting uses lines
10
to
20
of the VBI to transport nearly any type of data along with the Several Television data broadcasting systems are known for delivering certain forms of data over a standard TV signal. One such system is the North American Basic Teletext Specification (NABTS) that provides an open standard for the transmission of data over the television, which system equipment is manufactured by Norpak Corporation, Kanata, Ontario. Another system is being offered by Radio Telephone and Television Corporation. As the data is encoded as video it becomes an integral part of the TV signal and, thus, the VBI data is transmitted everywhere that the television signal reaches and furthermore can pass transparently through all carrier media (VHF, UHF, cable, satellite, wireless cable, BTV networks, fiber optic cable, ITFS, etc.). Known VBI systems include a data insertion system at the television network “head end” and an inexpensive VBI data or graphics receiver at each site.
Because VBI data broadcasting only transmits data in only one direction, i.e., high speed, one-way, point-to-multipoint data transmission medium, there is a longfelt need for two-way VBI data broadcasting. As is more fully described herein, the present invention provides such a two-way communication system that utilizes the VBI of the television signal. A VBI data broadcasting system is disclosed in U.S. Pat. No. 5,321,514 to Martinez. The Martinez patent discloses an interactive television and data transmission system that provides transmission of information to multiple users. However, the Martinez patent uses a second carrier for transmitting the down link signals on either the horizontal or vertical blanking intervals and another carrier for transmitting uplink signals.
SUMMARY OF THE INVENTION
Generally, the enhanced PCS communication system of the present invention includes a broadcast means for encoding and broadcasting digital messages on the vertical blanking interval (“VBI”) of a television broadcast. The out-going signal with the embedded VBI message is received by a low power VBI transceiver or, alternatively, a VBI/PCS composite transceiver for receiving and transmitting messages for VBI and/or PCS communications. Such transceiver includes an antenna capable of transmitting a return signal or message on the same VBI carrier at low power and relatively low frequencies. The return signal is detected by a return signal processor located at the broadcast means, such return signal processor being able to extract the faint (low power) return signal from the VBI, process the message and to transmit such message to its ultimate address via an interface with one of a satellite communications network, commercial land-lines or the like.
Specifically, the present invention provides a wireless digital communication system having a broadcast interface for encoding message information on the vertical blanking interval (VBI) of a video signal, the message information is encoded to a VBI format so as to form a pre-formatted signal. A broadcast device for transmitting an out-going signal having the pre-formatted signal modulated or otherwise embedded in the VBI of the video signal. The pre-formatted signal is received from the broadcast interface and is transmitted on a carrier of the out-going signal. At least one transceiver exists for receiving the out-going signal and for transmitting a return signal on the carrier of the out-going signal, the transceiver detects clock information relating to the synchronization bits of the broadcast and further includes a decoder for identifying the pre-formatted signal from the out-going signal so as to allow for the decoding of the message information and for displaying suc
James Randy
Nash, II Dallas L.
Rogers Jimmy L.
Ferguson Keith
McDermott & Will & Emery
Tsang Fan
VBI-2000, L.L.C.
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