Enhanced sleep mode in radiocommunication systems

• US 5,539,748 A
• Filed: 10/31/1994
• Issued: 07/23/1996
• Est. Priority Date: 11/01/1993
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Raith, Alex K.
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): Patel, Ajit
• Application Number:
  US08/331,951
• Time in Patent Office: 631 Days
• Field of Search: 370/95.1, 370/95.3, 455/54.1, 455/53.1, 455/32.1, 455/68, 455/70, 455/343, 455/127, 455/62, 455/33.1, 455/38.3, 455/34.1, 455/34.2, 340/825.06, 340/825.44, 379/57-59, 379/60
• US Class Current: 370/329
• CPC Class Codes: H04B 7/2643 using time-division multiple access [TDMA] H04B7/2615, H04B7/2618 take precedence
• CPC Class Codes: H04B 7/2656 for structure of frame, burst
• CPC Class Codes: H04L 1/0002 by adapting the transmission rate
• CPC Class Codes: H04L 1/0046 Code rate detection or code type detection H04L1/0038 takes precedence; detection of the data rate H04L25/0262; for packet format H04L1/0091
• CPC Class Codes: H04L 1/0056 Systems characterized by the type of code used H04L1/08 takes precedence
• CPC Class Codes: H04L 1/0057 Block codes H04L1/0061, H04L1/0064 take precedence
• CPC Class Codes: H04L 1/0059 Convolutional codes
• CPC Class Codes: H04L 1/0061 Error detection codes
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 1/0072 Error control for data other than payload data, e.g. control data
• CPC Class Codes: H04L 1/0083 Formatting with frames or packets; Protocol or part of protocol for error control
• CPC Class Codes: H04L 1/08 by repeating transmission, e.g. Verdan system H04L1/1858 and H04L1/189 take precedence
• CPC Class Codes: H04L 1/1614 using bitmaps
• CPC Class Codes: H04L 1/1685 the supervisory signal being transmitted in response to a specific request, e.g. to a polling signal
• CPC Class Codes: H04L 1/18 Automatic repetition systems, e.g. Van Duuren systems
• CPC Class Codes: H04L 1/1803 Stop-and-wait protocols
• CPC Class Codes: H04L 1/1809 Selective-repeat protocols
• CPC Class Codes: H04L 1/1848 Time-out mechanisms
• CPC Class Codes: H04L 1/188 Time-out mechanisms
• CPC Class Codes: H04L 1/20 using signal quality detector
• CPC Class Codes: H04L 2001/0093 : Point-to-multipoint
• CPC Class Codes: H04L 9/40 : Network security protocols
• CPC Class Codes: H04W 36/30 : by measured or perceived connection quality data
• CPC Class Codes: H04W 48/10 : using broadcasted information
• CPC Class Codes: H04W 48/16 : Discovering, processing access restriction or access information
• CPC Class Codes: H04W 48/20 : Selecting an access point
• CPC Class Codes: H04W 52/0212 : managed by the network, e.g. network or access point is master and terminal is slave
• CPC Class Codes: H04W 52/0245 : according to signal strength
• CPC Class Codes: H04W 68/00 : User notification, e.g. alerting and paging, for incoming communication, change of service or the like
• CPC Class Codes: H04W 68/025 : Indirect paging
• CPC Class Codes: H04W 88/02 : Terminal devices
• CPC Class Codes: Y02D 30/70 : in wireless communication networks

Abstract

A method and system for providing an enhanced sleep mode for remote units in a radiocommunication system are described. Measurement periodicity for control channels of neighboring cells is optimized. Paging frame classes can also be temporarily modified to extend sleep periods.

Claims

1. A method for evaluating a plurality of control channels in a radiocommunication system comprising the steps of:

providing a default frequency of signal strength measurement for at least one of said plurality of control channels to be made by a remote station which is being served by a current control channel;

reducing said default frequency of signal strength measurement for at least one of said plurality of control channels if said current control channel has been serving said remote station for greater than a predetermined time period; and

scanning, at said remote station, said at least one of said plurality of control channels at said reduced default frequency signal strength measurement.

2. The method of claim 1, wherein said step of providing further comprises the step of:

transmitting, on said current control channel, said default frequency for scanning by said remote station.

3. A method for evaluating a plurality of control channels in a radiocommunication system comprising the steps of:

providing a default frequency of signal strength measurement for at least one of said plurality of control channels to be made by a remote station;

reducing said default frequency of signal strength measurement for at least one of said plurality of control channels if a first change of an average received signal strength on a current serving control channel is less than a first predetermined threshold and if a second change of an average received signal strength on said plurality of control channels is less than a second predetermined threshold; and

measuring, at said remote station, a signal strength of said at least one of said plurality of control channels at said reduced frequency of signal strength measurement.

4. The method of claim 3, wherein said step of providing further comprises the step of:

transmitting, on said current control channel, said default frequency of signal strength measurement to be made by said remote station.

5. A method for evaluating a plurality of control channels in a radiocommunication system comprising the steps of:

providing a default frequency of signal strength measurement for at least one of said plurality of control channels to be made by a remote station;

reducing said default frequency of signal strength measurement for at least one of said plurality of control channels if a change of a difference between an average received signal strength of a current serving control channel and one of said plurality of control channels is less than a predetermined threshold; and

measuring, at said remote station, a signal strength of said at least one of said plurality of control channels at said reduced frequency of signal strength measurement.

6. The method of claim 5, wherein said step of providing further comprises the step of:

transmitting, on said current control channel, said default frequency of signal strength measurement to be made by said remote station.

7. A remote station comprising:

a receiver for receiving, on a current control channel which is serving said remote stations, neighboring lists identifying other control channels;

means for scanning said other control channels at a default scanning rate; and

means for reducing said default scanning rate for at least one of said other control channels if said current control channel has been serving said remote station for greater than a predetermined time period.

8. The remote station of claim 7, wherein said default scanning rate is received by said receiver in supervisory data messages.

9. A remote station comprising:

a receiver for receiving, on a current control channel, neighboring lists identifying other control channels;

means for scanning said other control channels at a default scanning rate; and

means for reducing said default scanning rate for at least one of said other control channels if a change of an average received signal strength on said current control channel is less than a first predetermined threshold and if a change of an average received signal strength on said other control channels is less than a second predetermined threshold.

10. The remote station of claim 9, wherein said default scanning rate is received by said receiver in supervisory data messages.

11. A remote station comprising:

a receiver for receiving, on a current control channel, neighboring lists identifying other control channels;

means for scanning said other control channels at a default scanning rate; and

means for reducing said default scanning rate for at least one of said other control channels if a change of a difference between an average received signal strength of said current control channel and one of said plurality of control channels is less than a predetermined threshold.

12. The remote station of claim 11, wherein said default scanning rate is received by said receiver in supervisory data messages.

13. A method for scanning a plurality of control channels by a remote station which is listening to a serving control channel comprising the steps of:

providing a default scanning frequency for said plurality of control channels for use by said remote station; and

if said serving control channel has been serving said remote station for greater than a predetermined period of time, then modifying said default scanning frequency for at least one of said plurality of control channels.

14. The method of claim 13, wherein said at least one of said plurality of control channels is provided to said remote station in a neighbor list.

15. The method of claim 13, wherein said at least one of said plurality of control channels includes all control channels which are provided to said remote station on a neighbor list.

16. The method of claim 13, wherein said at least one of said plurality of control channels includes all control channels which are provided to said remote station on a neighbor list and said serving control channel.

17. The method of claim 13, further comprising the step of:

returning to said default scanning frequency if said serving channel is changed.

18. The method of claim 13, wherein said plurality of control channels to be scanned include said serving control channel.

19. The method of claim 13, wherein said step of modifying further includes the step of:

reducing said default scanning frequency.

20. A method for scanning a plurality of control channels by a remote station which is listening to a serving control channel comprising the steps of:

providing a default scanning frequency for said plurality of control channels; and

if a change in an average received signal strength on said serving control channel is less than a predetermined threshold for a predetermined period of time, then modifying said default scanning frequency for at least one of said plurality of control channels.

21. The method of claim 20, wherein said at least one of said plurality of control channels is a control channel provided to said remote station in a neighbor list.

22. The method of claim 20, wherein said at least one of said plurality of control channels includes all control channels which are provided to said remote station on a neighbor list.

23. The method of claim 20, wherein said at least one of said plurality of control channels includes all control channels which are provided to said remote station on a neighbor list and said serving control channel.

24. The method of claim 20, further comprising the step of:

returning to said default scanning frequency if said change is no longer less than said predetermined threshold.

25. The method of claim 20, wherein said at least one of said plurality of control channels includes said serving control channel.

26. A method for scanning a plurality of control channels by a remote station which is listening to a serving control channel comprising the steps of:

providing a default scanning frequency for said plurality of control channels; and

if a difference between a change in an average received signal strength on said serving control channel and a change in an average received signal strength on one of said plurality of control channels is less than a predetermined threshold for a predetermined period of time, then modifying said default scanning frequency for at least one of said plurality of control channels.

27. The method of claim 26, wherein said at least one of said plurality of control channels is said serving control channel.

28. The method of claim 26, wherein said at least one of said plurality of control channels is all of said plurality of control channels.

29. The method of claim 26, further comprising the step of:

returning to said default scanning frequency if said change is no longer less than said predetermined threshold.

30. A method for scanning a plurality of control channels by a remote station which is listening to a serving control channel comprising the steps of:

providing a default scanning frequency for said plurality of control channels; and

if a change in a difference between an average received signal strength on said serving control channel and an average received signal strength on one of said plurality of control channels is less than a predetermined threshold for a predetermined period of time, then modifying said default scanning frequency for at least one of said plurality of control channels.

31. The method of claim 30, wherein said at least one of said plurality of control channels is said serving control channel.

32. The method of claim 30, wherein said at least one of said serving control channel and said plurality of control channels is all of said plurality of control channels.