Radio telephones and methods of operation

• US 6,631,264 B1
• Filed: 06/17/1999
• Issued: 10/07/2003
• Est. Priority Date: 06/26/1998
• Status: Expired due to Fees

• Current Assignee: Nokia Solutions and Networks US LLC (Nokia Corporation)
• Original Assignee: Nokia Mobile Phones UK Limited (Nokia Corporation)
• Inventors: Tat, Nguyen Quan, Leickel, Torsten
• Primary Examiner(s): Nguyen, Lee
• Assistant Examiner(s): CRAVER, CHARLES R
• Application Number:
  US09/335,174
• Time in Patent Office: 1,573 Days
• Field of Search: 455/434, 455/437, 455/435, 455/436, 455/464, 455/67.3, 455/67.4, 455/62, 455/63, 455/556-557, 455/226.2, 455/226.3, 455/438, 455/439, 455/450, 455/509
• US Class Current: 455/437
• CPC Class Codes: H04B 17/318 Received signal strength
• CPC Class Codes: H04W 36/30 by measured or perceived connection quality data
• CPC Class Codes: H04W 52/0229 where the received signal is a wanted signal
• CPC Class Codes: H04W 52/0245 according to signal strength
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

An apparatus and method for reducing battery consumption in a radio telephone by scanning for additional local base stations when a currently monitored signal from a local base station is deteriorating.

Claims

1. A radio telephone for communication in a radio system having a plurality of system channels for allowing communication on a selected system channel between the radio telephone and a base station which transmits signals on the selected system channel, the radio telephone comprising:

processing means operative, for monitoring a signal transmitted by a base station on one of the plurality of system channels to determine whether the signal has a parameter that meets a predetermined criterion, in response to the monitored signal meeting the predetermined criterion, and when a previous scanning operation has determined that no other system channel exists on which a base station is transmitting a signal, scanning respective system channels and selecting a different transmitted signal for monitoring, and in response to an indication that a system channel is required for a call, scanning the respective system channels for an available system channel on the base station transmitting the monitored signal.

2. A radio telephone according to claim 1, wherein the parameter is the strength of the monitored signal.

3. A radio telephone according to claim 2, wherein the strength of the signal is determined by its RSSI.

4. A radio telephone according to claim 3, wherein the predetermined criterion is the parameter falling beyond a predetermined unit.

5. A radio telephone according to claim 4, wherein the predetermined limit is set in absolute terms.

6. A radio telephone according to claim 5, wherein the radio telephone is operative to determine if it is operating in a first or second environment.

7. A radio telephone according to claim 4, wherein the predetermined limit is set relative to the initial value of the parameter.

8. A radio telephone according to claim 7, wherein the radio telephone is operative to determine if it is operating in a first or second environment.

9. A radio telephone according to claim 4, wherein the radio telephone is operative to determine if it is operating in a first or second environment.

10. A radio telephone according to claim 3, wherein the radio telephone is operative to determine if it is operating in a first or second environment.

11. A radio telephone according to claim 2, wherein the radio telephone is operative to determine if it is operating in a first or second environment.

12. A radio telephone according to claim 1, wherein the predetermined criterion is the parameter falling beyond a predetermined limit.

13. A radio telephone according to claim 12, wherein the predetermined limit is set in absolute terms.

14. A radio telephone according to claim 13, wherein the radio telephone is operative to determine if it is operating in a first or second environment.

15. A radio telephone according to claim 12, wherein the predetermined limit is set to the initial value of the parameter.

16. A radio telephone according to claim 15, wherein the radio telephone is operative to determine if it is operating in a first or second environment.

17. A radio telephone according to claim 12, wherein the radio telephone is operative to determine if it is operating in a first or second environment.

18. A radio telephone according to claim 1, wherein the radiotelephone is operative to determine if it is operating in a first or second environment.

19. A radio telephone according to claim 18, wherein if the radio telephone determines that it is operating in the first environment all scans to monitor channels for additional local base stations are suspended.

20. A radio telephone according to claim 19, wherein the radio telephone is operative to determine if it is operating in the first or second environment by monitoring messages transmitted by a selected base station.

21. A radio telephone according to claim 18, wherein the radio telephone is operative to determine if it is operating in the first or second environment by monitoring messages transmitted by a selected base station.

22. A radio telephone according to claim 2, wherein the predetermined criterion is the parameter falling beyond a predetermined unit.

23. A radio telephone according to claim 22, wherein the predetermined limit is set in absolute terms.

24. A radio telephone according to claim 23, wherein the radio telephone is operative to determine if it is operating in a first or second environment.

25. A radio telephone according to claim 22, wherein the predetermined limit is set relative to the initial value of the parameter.

26. A radio telephone according to claim 25, wherein the radio telephone is operative to determine if it is operating in a first or second environment.

27. A radio telephone according to claim 22, wherein the radio telephone is operative to determine if it is operating in a first or second environment.

28. A method of operating a radio telephone in a radio system having a plurality of system channels allowing communication on a selected system channel between the radio telephone and a base station which transmits signals on the selected system channel, said method comprising:

monitoring a signal transmitted by a base station on one of the plurality of system channels to determine whether the signal has a parameter that meets a predetermined criterion;

in response to the monitored signal meeting the predetermined criterion, and when a previous scanning operation has determined that no other system channel exists on which a base station is transmitting a signal, scanning respective system channels and selecting a different transmitted signal for monitoring; and

in response to an indication that a system channel is required for a call, scanning the respective system channels for an available system channel on the base station transmitting the monitored signal.

29. A method according to claim 28, wherein scanning to identify a local base station is suspended if the system has only one base station.