SPREAD-SPECTRUM DATA PUBLISHING SYSTEM

Abstract: A system for publishing data (409) on shared broadcast channels using spread-spectrum techniques, which may comprise a spread-spectrum encoder (405) capable of receiving data and placing it in a spread-spectrum signal format (407) and a transmitter (406) operating on a shared communication channel or frequency band, such as might be allocated to terrestrial point-to-point or broadcast communications. The shared communication channel may comprise a cellular system, in which data (409) may be transmitted (406) using spread-spectrum techniques using the transmitters (406) and repeaters of the cellular system simultaneously with voice and other transmissions associated with the cellular system. A subscriber station may be capable of receiving using a plurality of different communication channels or frequency bands, such as a first receiver capable of cellular reception and a second receiver capable of satellite reception, at least one of which uses spread-spectrum techniques. The subscriber station may also comprise a transmitter using at least one communication channel or frequency band, so that the subscriber station may receive data or other transmissions using one channel and may request further data or other transmissions using a second channel.

Description: DESCRIPTION Spread-Spectrum Data Publishing System Background Of The Invention 1. Field of the Invention This invention relates to a system for publishing data by broadcast or related technology. More specifically, this invention relates to a system for publishing data on shared channels using spread-spectrum techniques. 2. Description of Related Art Data publishing is the process of transmitting data to recipients by means of electronic communication channels, such as broadcast or related communication methods. One motive for data publishing is that it may be easier or less expensive to transmit data to recipients by means of broadcast than it would be to write that data onto physical media (such as paper or magnetic disks or tapes) and carry the physical media to them. Another motive is that the marginal cost of publishing the same data to an additional recipient may be comparatively small. Data publishing may be particularly advantageous when the data to be published are voluminous, rapidly changing, or must be delivered within a short time to be useful. A classic example of such data is stock-market trading data, although there are many other cases where data publishing would be advantageous. One problem which has arisen in the art is the lack of sufficient broadcast infrastructure for data publishing. There are few if any broadcast towers, repeaters, or receivers for use with data publishing, so it has been generally necessary to use infrastructure which is already associated with another form of communication. Hence the use of telephone, television, radio and satellite systems noted above. Accordingly, it would be advantageous to provide a method of data publishing which did not require construction of large amounts of additional infrastructure. Another problem which has arisen in the art is that it may be difficult to obtain sufficient bandwidth, at reasonable cost and without excessive difficulty, to publish the data. Lack of bandwidth naturally either reduces the amount of data which can be published, or increases the amount of time which is required to publish the data to recipients. One method of the prior art is to make use of spare bandwidth from an extant communication system. Examples include telephone (using data-over-voice) , television (using vertical blanking intervals) , and radio (using FM sidebands) systems. While this method achieves a limited degree of success, it has been subject to the drawback that it has not been able to deliver bandwidth to support publishing of large amounts of data. For example, while television systems have a great deal of broadcast bandwidth, the amount of bandwidth for data publishing available by means of the vertical blanking interval is relatively limited. Another problem is that this prior art method does not generally provide national coverage. Another method of the prior art is to allocate separate frequency bands in which to publish the data. Examples of this method include satellite systems with dedicated channels. While this method is able to deliver a greater amount of bandwidth for data publishing, it has been subject to the drawback that allocation of separate frequency bands for data publishing may generally require proceedings before the FCC or other government agencies. Another method of the prior art is to use leased lines or other telephone lines to publish the data serially to multiple receiving sites. While this method is able to deliver the data * to receiving sites, it has been subject to the drawback that it requires a great deal of money in leased line charges or telephone charges, and therefore may not be economical. Accordingly, it would be advantageous to provide a method of data publishing which allowed easier access to sufficient bandwidth for data publishing. Summary Of The Invention The invention provides a system for publishing data on shared broadcast channels using spread-spectrum techniques. The system may comprise a spread-spectrum encoder capable of receiving data and placing it in a spread-spectrum signal format and a transmitter operating on a shared communication channel or frequency band, such as might be allocated to terrestrial point-to-point or broadcast communications. In a preferred embodiment, the shared communication channel may comprise a cellular system, in which data may be transmitted using spread- spectrum techniques using the transmitters and repeaters of the cellular system simultaneously with voice and other transmissions associated with the cellular system. In a preferred embodiment, a subscriber station may be capable of receiving using a plurality of different communication channels or frequency bands, such as a first receiver capable of cellular reception and a second receiver capable of satellite reception, at least one of which uses spread-spectrum techniques. The subscriber station may also comprise a transmitter using at least one communication channel or frequency band, so that the subscriber station may receive data or other transmissions using one channel and may request further data or other transmissions using a second channel. For example, the subscriber station may comprise a cellular transmitter and receiver, and a satellite receiver. Brief Description Of The Drawings Figure 1 shows a block diagram of a system for data publishing. Figure 2 shows a block diagram of a cellular system communication channel in a system for data publishing. Figure 3 shows a block diagram of a subscriber station. Figure 4 shows a block diagram of a transmitter station. Description Of The Preferred Embodiment Figure 1 shows a block diagram of a system for data publishing. A system for data publishing may comprise a data source 101, a transmitter station 102, a communication channel 103, and a subscriber station 104. The data source 101 may originate the data to be published (or may format it for publication) . The transmitter station 102 may receive the data and place it in a spread-spectrum signal format for transmission over the communication channel 103. The communication channel 103 may couple the data (in a spread-spectrum signal format) to one or more subscriber stations 104. The subscriber stations 104 may receive the data and decode it from the spread-spectrum forma . In a preferred embodiment, the data source 101 may originate (or format) a variety of different types of data to be published. These may include: text, graphics, digitized voice, digitized images or moving video, or mixed media; financial, news and weather data, including digitized photos and weather maps; airline and rail scheduling data; updates for in-store retail displays, including high-resolution graphic advertisements and animation; credit and credit card data for in-store approval and verification; encyclopedia or other database contents, including chemical, legal, medical, and pharmacological databases, and advertising and telephone listings; high-quality telecopier images and other print images; and updates for documentation manuals, including airline, automotive and computer manuals. In a preferred embodiment, the subscriber stations 104 may each comprise a multitasking processor which may perform communication tasks in parallel with other tasks, and which may be coupled to a LAN (local area network) or WAN (wide area network) for retransmitting data to other cooperating processors. In a preferred embodiment, the communication channel 103 may comprise a satellite system 105, having an uplink station 106, a satellite and transponder 107 (preferably with a wide area footprint), and a downlink station 108, as is well known in the art of satellite communication. The uplink station 106 may be coupled to the transmitter station 102; the downlink station 108 may be coupled to the subscriber station 104 and may comprise an indoor mountable one-foot antenna, as is well known in the art of satellite communication. In a preferred embodiment, the transmitter station 102 and the subscriber station 104 may comprise inventions disclosed in U.S. Patents 5,016,255 and 5,022,047, and in application Serial No. 07/556,147 filed July 23, 1990, 07/562,867 filed August 6, 1990, 07/600,772 filed October 23, 1990, 07/698,450 filed May 10, 1991, 07/698,458 filed May 10, 1991, and 07/698,694 filed May 13, 1991, all of which are hereby incorporated by reference as if fully set forth herein, and the spread-spectrum signal format may comprise signal formats disclosed therein. Figure 2 shows a block diagram of a cellular system communication channel in a system for data publishing. In a preferred embodiment, the communication channel 103 may comprise a shared communication channel or frequency band, such as might be allocated to terrestrial point-to-point or broadcast communications. In particular, in a preferred embodiment, the communication channel 103 may comprise a cellular system 109, with a set of base stations 110 and a set of cells 111. In the cellular system 201, the data to be published may be transmitted using the frequency bands allocated to the cellular system 201, from the transmitter station 102 to a transmitter base station 202, to a receiver base station 202 (possibly by means of a set of repeaters 112) , to a user station 113. In a preferred embodiment, the transmitter station 102 may be collocated with the transmitter base station 202, may be coupled thereto by means of cabling, and may even share the same antenna. Return messages may be transmitted from the user station 205 to the transmitter station 102 in like manner. Because the data to be published is transmitted in a spread-spectrum signal format, it may use the same frequency bands allocated to the cellular system 201 simultaneously with other transmissions associated with the cellular system 201 and without interfering with those other transmissions. Moreover, the data to be published (in its spread-spectrum signal format) may be routed in the cellular system 201 and transmitted from base station 202 to base station 202 without loss of data and without substantial modification of the cellular system 201. In a preferred embodiment, the cellular system 201 may comprise inventions disclosed in application Serial No. 07/682,050 filed April 8, 1991, 07/709,712 filed June 3, 1991 and 07/712,239 filed June 7, 1991, all of which are hereby incorporated by reference as if fully set forth herein. Figure 3 shows a block diagram of a subscriber station. In a preferred embodiment, the subscriber station 104 may comprise a first receiver 301 operating on a first communication channel 103 and a second receiver 301 operating on a second communication channel 103, at least one of which uses spread-spectrum techniques. For example, in a preferred embodiment, the first communication channel 103 may comprise the cellular system 201 shown in figure 2, and the second communication channel 103 may comprise the satellite system 105 shown in figure 1. In a preferred embodiment, the subscriber station 104 may also comprise a subscriber transmitter 302 operating on a third communication channel 103, and the transmitter station 102 may comprise a receiver operating on that third communication channel 103. For example, in a preferred embodiment, the third communication channel 103 may also comprise the cellular system 201 shown in figure 2 (i.e., the third communication channel 103 is the same as the first communication channel 103) , so that the cellular system 201 may be used for two-way communication between the transmitter station 102 and the subscriber station 104. The subscriber station 104 may thus receive data to be published (as well as other information described with reference to figure 1) , and respond, by means of the cellular system 201. The response may comprise a request for further data or other transmissions by means of the satellite system 105, and the transmitter station 102 may answer that request with further data transmitted by means of the satellite system 105. Figure 4 shows a block diagram of a transmitter station. The transmitter station 102 may comprise a formatting module 401 for receiving data from the data source 101, a data compression module 402, an error correction module 403, a message encoding module 404, a spread-spectrum encoding module 405, and a transmitting antenna 406. In a preferred embodiment, the formatting module 401 may comprise a buffer 407 for receiving data from the data source, and may generate a message signal 408 comprising the data to be published 409 and message packaging data 410, as is well known in the art of message transmission protocols. For example, in a preferred embodiment, messages may be addressed to individual subscriber stations 104 by indicating a 32-bit individual address in the message packaging data 410. In a preferred embodiment, the formatting module 401 may format data for a plurality of data channels, may multiplex the data to be published on each data channel, and may divide each data channel into up to 256 logical subchannels. In combination with a request by the subscriber station 104 for particular data or data services, the formatting module 401 may also generate usage data and related statistical data by review of the buffer 407 and the message packaging data 410. In a preferred embodiment, the formatting module 401 may generate usage data which correlates each subscriber station 104 with the data to be decoded by that subscriber station 104, and that usage data may be used to compute charges for subscribers stations 104 and to rate demand for particular data or data services. In a preferred embodiment, the formatting module 401 may format text data in ASCII format, and may format image data in bitmap format at a resolution of 300 x 300 dots per inch, or more preferably, 400 x 400 dots per inch. The data compression module 402 may encode the data to be published into a more compact form, as is well known in the art of data compression. In a preferred embodiment, the data compression module may use a group III data compression technique for data which is designated to be output to a telecopier. In a preferred embodiment, data compression module may use an ASCII compression technique for text data which is keyword searchable in compressed form, and may use a compression technique for image data which is automatically scaled for output to lower resolution printers or for display on graphics monitor. Data compression techniques which do not use "alphabet extension" are preferred. The error correction module 403 may encode the data to be published by adding error detection and correction information, as is well known in the art of error detection and correction. In a preferred embodiment, the error correction module 403 may use a forward error correction technique which adapts the degree of error detection and correction information to the type of data to be published, and which further adapts the degree of error detection and correction information to real-time error characteristics of the communication channel 103. The message encoding module 404 may encode the data to be published to preserve its security against unauthorized reception. In a preferred embodiment, the message encoding module 404 may use a nonlinear cipher feedback shift register technique which processes data at about 10 kilobytes per second. In a preferred embodiment, data to be published may be divided into "files" and each file encoded with a file-specific key, and when received at the subscriber station, re-encoded after receipt with a station-specific or device-specific key. In a preferred embodiment, the message encoding module 404 may comprise a hardware encoding device which encodes one byte at a time. Alternative Embodiments While preferred embodiments are disclosed herein, many variations are possible which remain within the concept and scope of the invention, and these variations would become clear to one of ordinary skill in the art after perusal of the specification, drawings and claims herein. In particular, a preferred embodiment of the invention is shown in which data to be published is broadcast by means of a satellite link from an transmitting station to a subscriber station. However, it would be clear to one of ordinary skill in the art, after perusal of the specification, drawings and claims herein, that the invention is also applicable to many different forms of transmission and media for broadcast. These many different forms of transmission and media for broadcast, would be workable, and are within the scope and spirit of the invention. For example, it would be clear to one of ordinary skill in the art that the invention would be equally workable with cable TV media, without essential change.

Claims: Claims 1. A system for publishing data on shared broadcast channels using spread-spectrum techniques, comprising a spread-spectrum encoder capable of receiving data to be published and generating a signal including a representation of said data in a spread-spectrum format; and a transmitter coupled to said encoder for operating on a shared terrestrial communication channel. 2. A system as in claim 1, wherein said communication channel comprises a broadcast communication channel or a point-to-point communication channel. 3. A system as in claim 1, wherein said communication channel comprises a predetermined set of frequencies. 4. A system as in claim 1, wherein said communication channel comprises at least one frequency between about 1850 and about 2200 megahertz. 5. A system as in claim 1, wherein said communication channel comprises a cellular system. 6. A system as in claim 1, wherein said communication channel comprises a cellular system, and wherein said communication channel is shared with at least one further transmission associated with, said cellular system. 7. A system as in claim 1, wherein said communication channel is shared with at least one nondata transmission. 8. A system as in claim 1, wherein said communication channel is shared with at least one nondigital transmission. 9. A system as in claim 1, wherein said communication channel is shared with at least one voice transmission. 10. A system as in claim 1, comprising a subscriber station capable of receiving using a plurality of different communication channels. 11. A system as in claim 1, comprising a subscriber station capable of receiving using a plurality of different communication channels, said subscriber station comprising a first receiver capable of cellular reception and a second receiver capable of satellite reception, at least one of said first and second receivers using spread- spectrum techniques. 12. A system as in claim 1, comprising a subscriber station having means for transmitting information; said system comprising means for receiving said information. 13. A system as in claim 1, comprising a subscriber station having means for transmitting information; said system comprising means for receiving said information; wherein said means for transmitting information uses said shared terrestrial communication channel. 14. A system as in claim 1, comprising a subscriber station having means for receiving data on a first and a second channel, and means for transmitting a request to receive data on said second channel in response to data received on said first channel; said system comprising means for receiving said request and for transmitting data on said second channel in response thereto. 15. A system as in claim 1, comprising a subscriber station having a cellular transmitter and receiver, and a satellite receiver. 16. A method of publishing data on shared broadcast channels using spread-spectrum techniques, comprising the steps of receiving data to be published; generating a signal including a representation of said data in a spread-spectrum format; and transmitting said signal on a shared terrestrial communication channel. 17. A method as in claim 16, wherein said communication channel comprises a broadcast communication channel or a point-to-point communication channel. 18. A method as in claim 16, wherein said communication channel comprises a predetermined set of frequencies. 19. A method as in claim 16, wherein said communication channel comprises at least one frequency between about 1850 and about 2200 megahertz. 20. A method as in claim 16, wherein said communication channel comprises a cellular system. 21. A method as in claim 16, wherein said communication channel comprises a cellular system, and wherein said communication channel is shared with at least one further transmission associated with said cellular system. 22. A method as in claim 16, wherein said communication channel is shared with at least one nondata transmission. 23. A method as in claim 16, wherein said communication channel is shared with at least one nondigital transmission. 24. A method as in claim 16, wherein said communication channel is shared with at least one voice t ansmission. 25. A method as in claim 16, comprising the step of receiving data at a subscriber station using a plurality of different communication channels. 26. A method as in claim 16, comprising the step of receiving data at a subscriber station using a first receiver capable of cellular reception and a second receiver capable of satellite reception, at least one of said first and second receivers using spread-spectrum techniques. 27. A method as in claim 16, comprising the steps of transmitting information from a subscriber station; and receiving said information. 28. A method as in claim 16, comprising the steps of transmitting information from a subscriber station; and receiving said information; wherein said step of transmitting information uses said shared terrestrial communication channel. 29. A method as in claim 16, comprising the steps of receiving data at a subscriber station on a first and a second channel; transmitting a request to receive data on said second channel in response to data received on said first channel; and receiving said request and transmitting data on said second channel in response thereto. 30. In a system for publishing data on shared terrestrial communication channels using spread-spectrum techniques, a subscriber station capable of receiving using a plurality of different communication channels. 31. A system as in claim 30, wherein said plurality of different communication channels comprises a first cellular channel and a second satellite channel, at least one of said first and second channels using spread- spectrum techniques. 32. A system as in claim 30, wherein said subscriber station comprises a transmitter for operating on a shared terrestrial communication channel. 33. A system as in claim 30, wherein said subscriber station comprises means for receiving data on a first and a second channel; and means for transmitting a request to receive data on said second channel in response to data received on said first channel. 34. A system as in claim 30, wherein said subscriber station comprises a cellular transmitter and receiver, and a satellite receiver. 35. In a method of publishing data on shared terrestrial communication channels using spread-spectrum techniques, the step of receiving data at a subscriber station using a plurality of different communication channels. 36. A method as in claim 35, wherein said plurality of different communication channels comprises a first cellular channel and a second satellite channel, at least one of said first and second channels using spread- spectrum techniques. 37. A method as in claim 35, comprising the step of transmitting information from said subscriber station on a shared terrestrial communication channel. 38. A method as in claim 35, comprising the steps of receiving data at said subscriber station on a first and a second channel; and transmitting a request to receive data on said second channel in response to data received on said first channel. 39. In a system for publishing data on shared broadcast channels using spread-spectrum techniques, a powered electromagnetic signal comprising a representation in a spread-spectrum format of data to be published, spread over a frequency band corresponding to a shared terrestrial communication channel, overlaid with at least one further transmission associated with said shared terrestrial communication channel. 40. In a system for publishing data on shared broadcast channels using spread-spectrum techniques, a powered electromagnetic signal comprising a representation in a spread-spectrum format of data to be published, spread over a frequency band corresponding to a cellular communication channel, overlaid with at least one further transmission associated with said cellular system. 41. In a system for publishing data on shared broadcast channels using spread-spectrum techniques, a powered electromagnetic signal comprising a representation in a spread-spectrum format of data to be published, spread over a frequency band comprising at least one frequency between about 1850 and about 2200 megahertz.

Inventors: SMITH DOUGLAS G, SMITH, DOUGLAS, G.
Applicants: OMNIPOINT CORP, OMNIPOINT CORPORATION
Application year: 1992
Main classification: H04K1
IPC codes: H04B7, H04H20, H04J13, H04W4