Cordless telephone micro-cellular system

• US 5,513,248 A
• Filed: 06/10/1994
• Issued: 04/30/1996
• Est. Priority Date: 12/02/1991
• Status: Expired due to Term

• Current Assignee: AT&T IPM Corp. (AT&T, Inc.)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Panagopoulos, Gregory, Evans, James G., Lehder, Diane Z.
• Primary Examiner(s): Bost, Dwayne D.
• Application Number:
  US08/258,353
• Time in Patent Office: 690 Days
• Field of Search: 379/58, 379/59, 379/60, 379/61, 379/62, 379/63, 379/64, 455/33.1, 455/33.2, 455/54.1, 455/56.1, 370/110.4
• US Class Current: 455/465
• CPC Class Codes: H04M 1/733 with a plurality of base stations connected to a plurality of lines for selection in cordless PBX H04W84/16
• CPC Class Codes: H04W 84/16 WPBX [Wireless Private Branch Exchange]

Abstract

A cordless telephone system is arranged for extending the operating range of a cordless telephone portable unit within such system. The cordless telephone system comprises a plurality of cordless telephone stations that plug into any available wall telephone jack and may share the intrapremises telephone wire-pair with one or more existing corded telephone stations without interference. Each cordless telephone station consists of a cordless telephone base unit and its associated cordless telephone portable unit. Although each of the portable units is associated with a particular base unit, all of the portable units are able to operate with any of the base units in the system. As a user of a portable unit with a call in progress roams about a premises, all base units monitor the quality of the radio frequency signal received from the portable unit. If the signal quality of a base unit actively communicating with the portable unit deteriorates to below an acceptable level, control apparatus in the system identifies another base unit and executes a hand-off of the communication link with the portable unit to this base unit that is then receiving the signal from the handset unit with an acceptable signal quality. Operational control for the base units is provided through a time division multiple access arrangement wherein a communications channel is imposed on the existing premises telephone wire-pair above the audio frequency band used for standard telephone service.

Claims

1. A cordless telephone system comprising:

at least one handset unit;

at least two base units for communicating with the handset unit over a communication channel, the base units being dispersible so as to divide a location of the telephone system into reception areas for telephone service with the handset unit;

means for commonly connecting the base units to a telephone line for communicating with a telephone line switching system; and

control means for determining when said handset unit is within reception range of at least one of the base units, said control means being operable in conjunction with the base units for receiving information data for each handset unit from each of the base units for switching the telephone service for the handset unit between the base units, the control means including communication means for both receiving said information data from each base unit and providing control switching signals for each base unit over a channel imposed on the telephone line above an audio frequency band used in the telephone line for telephone service, the audio frequency band containing voice signals that are provided between the base units and the telephone line switching system.

2. The cordless telephone system of claim 1 wherein the control means is associated with each one of the base units.

3. The cordless telephone system of claim 1 wherein the control means is associated with a predetermined one of the base units.

4. The cordless telephone system of claim 1 wherein the control means comprises a control unit connected to each of the base units through the telephone line.

5. The cordless telephone system of claim 1 wherein the communication means receives said information data from each base unit and provides control switching signals for each base unit through a time division multiple access arrangement over said channel.

6. The cordless telephone system of claim 1 wherein the telephone line is a telephone wire pair.

7. In a cordless telephone system including at least one handset unit and at least two base units for communicating with the handset unit, the base units being commonly connected to a telephone line and dispersible so as to divide a location of the telephone system into reception areas for providing telephone service with the handset unit over the telephone line, at least one of the base units comprising:

means for communicating with the handset unit over a radio frequency channel; and

control means for determining when said handset unit is within reception range of at least one of the base units, said control means being operable in conjunction with the base units for receiving information data for each handset unit from each of the base units for switching the telephone service for the handset unit between the base units, the control means including communication means for both receiving said information data from each base unit and providing control switching signals for each base unit over a channel imposed on the telephone line above an audio frequency band used in the telephone line for telephone service, the audio frequency band containing voice signals that are provided between the base units and the telephone line switching system.

8. The cordless telephone system of claim 7 wherein the control means is associated with each one of the base units.

9. The cordless telephone system of claim 7 wherein the control means is associated with a predetermined one of the base units.

10. The cordless telephone system of claim 7 wherein the control means comprises a control unit connected to each of the base units through the telephone line.

11. The cordless telephone system of claim 7 wherein the communication means receives said information data from each base unit and provides control switching signals for each base unit through a time division multiple access arrangement over said channel.

12. The cordless telephone system of claim 7 wherein the telephone line is a telephone wire pair.

13. A cordless telephone system including a plurality of handset units and a plurality of base units for communicating over a radio frequency channel with each one of the handset units, the telephone system comprising:

means for commonly connecting the plurality of base units to a telephone line, the base units being dispersible so as to divide a location of the telephone system into a number of reception areas for providing telephone service with the handset units; and

control means for determining when each handset unit is within reception range of at least one of the plurality of base units, said control means being operable in conjunction with the plurality of base units for receiving information data for each handset unit from each of the plurality of base units for switching the telephone service for each handset unit among the plurality of base units, the control means including communication means for both receiving said information data from each base unit and providing control switching signals for each base unit over a channel imposed on the telephone line above an audio frequency band used in the telephone line for telephone service, the audio frequency band containing voice signals that are provided between the base units and the telephone line switching system.

14. The cordless telephone system of claim 13 wherein each one of the plurality of base units includes means for selecting a specific one of the plurality of radio frequency channels for providing telephone service for each of the plurality of handset units.

15. The cordless telephone system of claim 13 wherein each base unit includes means for monitoring each radio frequency channel selected by each one of the plurality of base units for receipt of a request-for-service signal from any one of the plurality of handset units.

16. The cordless telephone system of claim 15 wherein responsive to the monitoring means, the plurality of base units in the system provides telephone service simultaneously for each one of the plurality of handset units in the system requesting service upon receipt of the request-for-service signal from these handset units.

17. The cordless telephone system of claim 13 wherein each base unit includes means for monitoring each radio frequency channel selected by each one of the plurality of base units, in response to the monitoring means, the base units providing telephone service to each one of the plurality of handset units during movement of the handset unit from a first reception area for a first one of the plurality of base units to a second reception area for a second one of the plurality of base units essentially without interruption over the selected communication channel.

18. The cordless telephone system of claim 17 wherein the control means includes means for controlling the selection of the identification code for use by a handset unit and for selection of the specific communication channel for use by this handset unit, the control means preventing the same identification code and communication channel from being assigned to more than one of the plurality of handset units.

19. The cordless telephone system of claim 13 wherein the communication means receives said information data from each base unit and provides control switching signals for each base unit through a time division multiple access arrangement over said channel.

20. The cordless telephone system of claim 13 wherein the telephone line is a telephone wire pair.

21. A method of extending the operating range of a cordless telephone having a plurality of handset units and a plurality of base units for communicating with the handset units over a communication channel, the base units being dispersible so as to divide a location of the telephone system into a number of reception areas for providing telephone service with the handset units, the method comprising the steps of:

commonly connecting the plurality of base units to a telephone line for communicating with a telephone line switching system; and

receiving information data for each handset unit from each of the plurality of base units, said information data from the plurality of base units being received over the telephone line;

determining when each handset unit is within reception range of at least one of the plurality of base units;

providing control switching signals to each one of the plurality of base units, the control switching signals switching the telephone service for each handset unit among the plurality of base units; and

providing over a channel imposed on the telephone line above an audio frequency band of the telephone line both the information data received from each base unit and the control switching signals provided to each base unit, the audio frequency band containing voice signals that are provided between the base units and the telephone line switching system.

22. The method of claim 21 wherein the providing step further includes the step of providing the control switching signals at each one of the plurality of base units.

23. The method of claim 21 wherein the providing step further includes the step of providing the control switching signals at a predetermined one of the plurality of base units.

24. The method of claim 21 wherein the providing step further includes the step of providing the control switching signals at a control unit connected to each of the plurality of base units through the telephone line.

25. The method of claim 21 further comprising the step of arranging the plurality of base units and the plurality of handset units to respectively communicate over any one of a plurality of communication channels.

26. The method of claim 25 further comprising the step of selecting a specific one of the plurality of communication channels by each one of the plurality of base units for providing telephone service for each of the plurality of handset units.

27. The method of claim 26 further comprising the step of monitoring each communication channel selected by each one of the plurality of base units for receipt of a request-for-service signal from any one of the plurality of handset units.

28. The method of claim 26 further comprising the steps of monitoring each communication channel selected by each one of the plurality of base units, and providing telephone service to one of the plurality of handset units during movement of the handset unit from a first reception area for a first one of the plurality of base units to a second reception area for a second one of the plurality of base units essentially without interruption over the selected communication channel.

29. The method of claim 21 further including the step of providing a time division multiple access arrangement for providing communications within said channel.

30. The method of claim 21 wherein the telephone line is a telephone wire pair.