Cellular data overlay system for storing data identifying selected data allocated channels

• US 5,396,539 A
• Filed: 12/03/1993
• Issued: 03/07/1995
• Est. Priority Date: 03/25/1991
• Status: Expired due to Term

• Current Assignee: Aviat Networks Canada ULC (Aviat Networks Incorporated)
• Original Assignee: Novatel Communications Incorporated
• Inventors: Gage, William A., Sharman, Duane, Andrietz, William E., Slekys, Arunas G.
• Primary Examiner(s): Kuntz, Curtis
• Assistant Examiner(s): CUMMING, WILLIAM D
• Application Number:
  US08/161,694
• Time in Patent Office: 459 Days
• Field of Search: 379/63, 379/57, 379/59, 370/50, 370/95.1, 455/33.1
• US Class Current: 455/426.1
• CPC Class Codes: H04L 1/18 Automatic repetition systems, e.g. Van Duuren systems
• CPC Class Codes: H04W 16/32 Hierarchical cell structures
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 72/542 using measured or perceived quality
• CPC Class Codes: H04W 76/28 Discontinuous transmission [DTX]; Discontinuous reception [DRX]
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals
• CPC Class Codes: H04W 88/10 adapted for operation in multiple networks, e.g. multi-mode access points

Abstract

A cellular telephone system includes a packet-switched digital data communication subsystem overlaying a circuit-switched (e.g., voice) communication subsystem, with voice and data services sharing the same voice channels. The voice communication subsystem provides voice services independently of the operation of the data communication subsystem. On the other hand, the data communication subsystem monitors use of the voice channels for voice communication, and, in response thereto, temporarily allocates one or more of the available voice channels for data service. In a preferred embodiment, each data basestation transmits, from time to time, an available-channel signature to identify those, if any, of the data-allocated channels that are not then being used to transmit voice or data. For data communication, a remote unit monitors selected voice channels in the coverage area of the cellular telephone system for available-channel signatures, selects one of the channels (if any) identified by the signature thereon as being available for data transmission, and transmits or receives digital information over that channel.

Claims

1. A cellular telephone system comprising:

A) a voice communication subsystem including at least one voice basestation for providing voice service over a plurality of voice channels; and

B) a data communication subsystem including at least one data basestation for providing data service over one or more of said voice channels;

C) wherein said voice basestation includes a voice basestation transceiver for transmitting a control signal over at least one control channel and a plurality of voice signals over said voice channels;

said voice communication subsystem providing said voice service independently of the data service of said data communication subsystem;

D) wherein said data communication subsystem includes basestation monitoring means for monitoring the voice service of said voice communication subsystem, a data basestation transceiver for transmitting data signals over said voice channels, and processor means responsive to said basestation monitoring means for controlling said data communication transceiver means so as to avoid having said transmitted data signals interfere with said voice service;

E) wherein said basestation monitoring means monitors use of said voice channels by said voice communication subsystem to identify the voice channel or channels which are not being used for voice service and, in response thereto, said data communication subsystem provides data service on one or more of said identified voice channels, and

F) wherein said basestation monitoring means monitors use of said identified voice channels for voice service by said voice communication subsystem while data service is being provided, and, in response thereto, said data communication subsystem terminates data service on any of said identified voice channels upon commencement of use by said voice communication subsystem of that channel for voice service.

2. A cellular telephone system comprising:

A) a voice communication subsystem including at least one voice basestation for providing voice service over a plurality of voice channels; and

B) a data communication subsystem including at least one data basestation for providing data service over one or more of said voice channels;

C) wherein said voice basestation includes a voice basestation transceiver for transmitting a control signal over at least one control channel and a plurality of voice signals over said voice channels;

said voice communication subsystem providing said voice service independently of the data service of said data communication subsystem;

D) wherein said data communication subsystem includes basestation monitoring means for monitoring the voice service of said voice communication subsystem, a data basestation transceiver for transmitting data signals over said voice channels, and processor means responsive to said basestation monitoring means for controlling said data communication transceiver means so as to avoid having said transmitted data signals interfere with said voice service; and

E) wherein said basestation monitoring means monitors use of said voice channels by said voice communication subsystem to identify the voice channel or channels on which voice service has begun, and, in response thereto, said data communication subsystem terminates data service on said voice channels identified as providing voice service.

3. The cellular telephone system in accordance with claim 2, wherein said basestation monitoring means includes means for scanning power levels of signals produced by said voice communication subsystem.

4. The cellular telephone system in accordance with claim 3, wherein said data communication subsystem identifies radio-frequency channels on which circuit-switched service has begun by monitoring circuit-switched service transmissions in said voice communication subsystem.

5. A cellular telephone system comprising:

A) a voice communication subsystem including at least one voice basestation for providing voice service over a plurality of voice channels; and

B) a data communication subsystem including at least one data basestation for providing data service over one or more of said voice channels;

C) wherein said voice basestation includes a voice basestation transceiver for transmitting a control signal over at least one control channel and a plurality of voice signals over said voice channels;

said voice communication subsystem providing said voice service independently of the data service of said data communication subsystem;

D) wherein said data communication subsystem includes basestation monitoring means for monitoring the voice service of said voice communication subsystem, a data basestation transceiver for transmitting data signals over said voice channels, and processor means responsive to said basestation monitoring means for controlling said data communication transceiver means so as to avoid having said transmitted data signals interfere with said voice service; and

E) wherein said data communication subsystem further includes at least one remote unit, said basestation transceiver transmitting, from time to time, an available-channel signature to said remote unit to identify those, if any, of the voice channels that are not then being used to transmit voice signals.

6. The cellular telephone system in accordance with claim 5, wherein said remote unit includes remote unit monitoring means for monitoring each of a plurality of selected voice channels for an available-channel signature, controller means coupled with and responsive to said remote unit monitoring means for selecting one of the channels, if any, identified by the signature thereon as being available for data transmission, and remote unit transceiver which transmits or receives data over that channel.

7. The cellular telephone system in accordance with claim 6, wherein said data basestation transceiver transmits data over said selected channel to said remote unit.

8. A cellular telephone system comprising:

A) a voice communication subsystem including at least one voice basestation for providing voice service over a plurality of voice channels; and

B) a data communication subsystem including at least one data basestation for providing data service over one or more of said voice channels;

C) a plurality of cells;

D) wherein said voice basestation includes a voice basestation transceiver for transmitting a control signal over at least one control channel and a plurality of voice signals over said voice channels;

said voice communication subsystem providing said voice service independently of the data service of said data communication subsystem;

E) wherein said data communication subsystem includes (i) basestation monitoring means for monitoring the voice service of said voice communication subsystem, (ii) a data basestation transceiver for transmitting data signals over said voice channels, and (iii) processor means responsive to said basestation monitoring means for controlling said data communication transceiver means so as to avoid having said transmitted data signals interfere with said voice service;

F) wherein said voice communication subsystem includes a voice basestation in each said cell, each said voice basestation having an associated control channel,

G) said data communication subsystem includes a data basestation associated with each said voice basestation, and at least one remote unit, each said data basestation including said basestation monitoring means for monitoring the voice service of the associated voice basestation, and

H) said processor means, in response to said basestation monitoring means, controlling data service so as to avoid interfering with voice service.

9. The cellular telephone system in accordance with claim 8, wherein said basestation monitoring means monitors use of said voice channels by said voice communication subsystem to identify the voice channel or channels which are not being used for voice service, and, in response thereto, said data communication subsystem provides data service on one or more of said identified voice channels.

10. The cellular telephone system in accordance with claim 8, wherein each said basestation monitoring means monitors use of said voice channels by said voice basestation to identify the voice channel or channels on which voice service has begun, and, in response thereto, each said data basestation terminates data service on said identified channels.

11. The cellular telephone system in accordance with claim 8, wherein each said basestation monitoring means includes means for detecting at least one of a plurality of signal characteristics of an output signal of the associated voice basestation on each of a plurality of voice channels, and, in response thereto, each said data basestation broadcasts an available-channel signature to indicate voice channels available for data transmission.

12. The cellular telephone system in accordance with claim 11, wherein said signal characteristics comprise the power of said output signals.

13. The cellular telephone system in accordance with claim 11, wherein said remote unit includes remote unit monitoring means for monitoring each of a plurality of selected voice channels for an available-channel signature;

a controller coupled with and responsive to said remote unit monitoring means for selecting one of the voice channels identified by the signature thereon as being available for data communication, and a remote unit transceiver coupled with said controller for transmitting digital information over that channel.

14. The cellular telephone system in accordance with claim 13, wherein said remote unit further includes remote unit memory means for storing data identifying a plurality of selected data-allocated channels corresponding to said control channels, and said controller is coupled with said remote unit memory means for determining which of said control channels carries the strongest signal, and using said stored data to identify at least one of the voice channels corresponding to said control channel that is to be monitored for an available-channel signature.

15. The cellular telephone system in accordance with claim 14, wherein said controller is responsive to said monitored available-channel signature for up-dating said data stored in said remote unit memory means with information obtained from said available-channel signature.

16. The cellular telephone system in accordance with claim 13, wherein said remote unit monitoring means monitors said selected voice channel for an available-channel signature prior to each of a plurality of data transmissions from said remote unit transceiver.

17. The cellular telephone system in accordance with claim 16, wherein said signal characteristics comprise radio-frequency power levels of the signals on each of said channels.

18. The cellular telephone system in accordance with claim 13, wherein said remote unit monitoring means monitors a plurality of said selected voice channels for available-channel signatures thereon, and said remote unit transceiver transmits data over one of said selected voice channels only upon said remote unit monitoring means receiving one of said available-channel signatures over said one selected voice channels.

19. The cellular telephone system in accordance with claim 8, wherein each said data basestation monitoring means monitors at least one of a plurality of signal characteristics on one or more of a plurality of voice channels over which said associated voice basestation transmits, to determine which of said voice channels is not then in use by said voice communication subsystem, and each said data basestation further includes a transceiver, which, in response to said monitoring means broadcasts an available-channel signature over one or more of said voice channels to indicate that one or more of said voice channels are available.

20. A cellular telephone system comprising:

A) a voice communication subsystem including at least one voice basestation for providing voice service over a plurality of voice channels; and

B) a data communication subsystem including at least one data basestation for providing data service over one or more of said voice channels;

C) wherein said voice basestation includes a voice basestation transceiver for transmitting a control signal over at least one control channel and a plurality of voice signals over said voice channels;

said voice communication subsystem providing said voice service independently of the data service of said data communication subsystem;

D) wherein said data communication subsystem includes basestation monitoring means for monitoring the voice service of said voice communication subsystem, a data basestation transceiver for transmitting data signals over said voice channels, and processor means responsive to said basestation monitoring means for controlling said data communication transceiver means so as to avoid having said transmitted data signals interfere with said voice service; and

E) wherein said data communication subsystem further includes a plurality of data remote units, and wherein each said data remote unit includes remote unit monitoring means for monitoring each of a plurality of selected voice channels for an available-channel signature, a controller coupled with said remote unit monitoring means for selecting one of the channels identified by the signature thereon as being available for data communication, and a transceiver for transmitting and receiving digital information over that channel.

21. The cellular telephone system in accordance with claim 20, wherein said data remote units further include remote unit memory means for storing data identifying at least one data-allocated channels.

22. The cellular telephone system in accordance with claim 21, wherein said controller up-dates the data stored in said remote unit memory means in response to information received in said available-channel signature.

23. A remote unit for data communication with a data basestation over a selected one of a plurality of data-allocated voice channels of a cellular telephone system comprising a plurality of voice basestations, each voice basestation associated with one of said data basestations and a control channel, said remote unit comprising:

transceiver means for transmitting and receiving digital signals; and

means for scanning the data-allocated voice channels to detect an available-channel signal transmitted by said data basestation that indicates voice channels that are not being used for voice communication and are therefore available for data transmission, and

controller means coupled with said transceiver means and said scanning means for identifying, in response to said available-channel signal, said voice channel to be used for data communication, and causing said transceiver means to transmit said digital signals over said voice channel so identified for data communication; and

memory means for storing data identifying selected data-allocated channels corresponding to said control channels, and wherein said controller means is coupled with said memory means and responsive to said available-channel signal for determining which of said control channels carries the strongest signal, and for using said stored data to identify the voice channels corresponding to said control channel that are to be scanned for said available channel signal.

24. The remote unit in accordance with claim 23, wherein said controller means, up-dates said data stored in said memory means with information obtained from said available-channel signal.

25. A cellular telephone system including a plurality of voice remote units equipped for voice communication, a plurality of data remote units equipped for data communication, a plurality of voice basestations, and a plurality of data basestations, said cellular telephone system providing primary voice communication between said voice remote units and said voice basestation, and data communication between said data remote units and said data basestations, each said voice and data remote unit and said voice and data basestation including at least one transceiver, and wherein

A) said system temporarily allocates a plurality of voice channels for packet-switched digital data service;

B) each said data basestation being associated with a corresponding one of said voice basestations, and further includes means coupled with said basestation transceiver for causing said basestation transceiver to transmit, from time to time, at least one available-channel signature identifying those, if any, of the data-allocated channels associated with the data basestation that are not being used by said corresponding voice basestation for voice communication and are therefore available for data communication; and

C) each said data remote unit further includes data transmission control means coupled to said remote-unit transceiver including

i) controller means coupled with said remote unit transceiver for selecting one of said data basestations with which the data remote unit is to establish data communication, said one data basestation being the selected data basestations; and

ii) means coupled with said controller means for monitoring the data-allocated channels associated with the selected data basestation for available-channel signatures;

said controller means selecting one of the channels identified by the available-channel signature thereon as being available for use in data communication with said data basestation, said one channel being the selected channel; and

causing said transceiver of said data remote unit to transmit data on said selected channel to said selected basestation.

26. A cellular telephone system in accordance with claim 25, wherein each said data remote unit further comprises a memory coupled to said data transmission control means for storing a look-up table identifying the selected channel associated with said data basestations.

27. A cellular telephone system in accordance with claim 26, wherein each said data basestation includes processor means for causing said basestation transceiver to transmit to said data remote units information for use by said controller means in up-dating the contents of the look-up table.

28. A cellular telephone system in accordance with claim 25, wherein said controller means causes said remote unit transceiver to terminate transmission of data after a pre-selected period of time.

29. A cellular telephone system in accordance with claim 25, wherein each said voice basestation is associated with a control channel over which said voice basestation transmits control signals, and said data transmission control means of each data remote unit selects said data basestation by identifying one of said control channels on the basis of signal strength.

30. A cellular telephone system in accordance with claim 29, wherein each said data remote unit further comprises memory means coupled to said data transmission control means for storing a look-up table identifying the selected data-allocated channels corresponding to each control channel, and thereby to each data basestation, and said data transmission control means monitors the data-allocated channels associated with the selected basestation for available-channel signatures.

31. A method for transmitting data over a cellular telephone system including a plurality of remote units equipped for voice communication, a plurality of remote units equipped for data communication, a plurality of voice basestations, and a plurality of data basestations, said cellular telephone system providing primary voice communication between said voice remote units and said voice basestation, and for communication between said data remote units and said data basestations, each said voice and data remote unit and said voice and data basestation including at least one transceiver, each of said voice basestations associated with a corresponding data basestation and a control channel over which said voice basestation transmits control signals, said method comprising the steps of

A) temporarily allocating a plurality of voice channels for packet-switched digital data service;

B) transmitting, from time to time, from each said data basestation, an available-channel signature identifying those, if any, of the data-allocated channels associated with said voice basestation corresponding to said data basestation which are then not being used for voice communication and are thereby available for data communication;

C) performing, on a data-call-by-data-call basis, the following sub-steps in each said data remote unit

i) selecting one of said data basestations with which the data remote unit is to establish data communication;

ii) monitoring the data-allocated channels associated with the selected basestation for available-channel signatures;

iii) selecting one of the channels identified by the signature thereon as being available for use in data communication with said data basestation; and

iv) causing said transceiver of said data remote unit to transmit data on said selected channel to said selected basestation.

32. The method for transmitting data over a cellular telephone system in accordance with claim 31, further comprising the step of maintaining look-up tables in said data remote units identifying selected data-allocated channels associated with each of said control channels, and wherein said basestation-selecting step includes the steps of obtaining the identity of the data-allocated channels from the look-up table corresponding to the strongest of the control signals, and said data-allocated-channel-monitoring step includes the step of monitoring only the identified, stored data allocated channels.

33. The method for transmitting data over a cellular telephone system in accordance with claim 32, wherein the look-up-table-maintaining step includes the step of up-dating the contents of the table with information provided from time to time by the data basestations.

34. The method for transmitting data over a cellular telephone system in accordance with claim 31, further including the step of terminating data transmission on commencement of voice communication over the selected channel by the corresponding voice basestation.

35. A cellular telephone system comprising:

A) a circuit-switched communication subsystem for providing circuit-switched communication service over a plurality of radio-frequency channels; and

B) a data communication subsystem for providing packet-switched data communication service over one or more of said radio-frequency channels;

C) said circuit-switched communication subsystem

i) using at least one control channel in association with said circuit-switched communication service; and

ii) providing said circuit-switched communication service independently of the packet-switched data communication data service of said data communication subsystem; and

D) said data communication subsystem including means for monitoring the circuit-switched communication service of said circuit-switched communication subsystem, and processor means for, in response thereto, controlling said packet-switched communication data service to avoid interfering with said circuit-switched communication service; and

E) wherein said means for monitoring the circuit-switched communication service of said circuit-switched communication subsystem monitors use of said radio-frequency channels by said circuit-switched communication subsystem to identify the radio-frequency channel or channels on which circuit-switched service has begun, and, in response thereto, terminates data service on said identified channels.

36. The cellular telephone system in accordance with claim 35, wherein said data communication subsystem identifies radio-frequency channels on which circuit-switched service has begun by monitoring power levels of signals produced by said circuit-switched communication subsystem.