Method and apparatus for relocating a beacon in a wireless system

• US 6,327,468 B1
• Filed: 11/10/1998
• Issued: 12/04/2001
• Est. Priority Date: 11/10/1998
• Status: Expired due to Term

• Current Assignee: Optis Wireless Technology, LLC (Brevet Capital)
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: van Iersel, Hans, van Puijenbroek, Corné
• Primary Examiner(s): Chang, Vivian
• Assistant Examiner(s): NGUYEN, DUC M
• Application Number:
  US09/189,814
• Time in Patent Office: 1,120 Days
• Field of Search: 455/434, 455/450, 455/515, 455/511, 455/451, 455/452, 455/509, 370/329, 370/343, 370/498
• US Class Current: 455/434
• CPC Class Codes: H04W 16/16 for PBS [Private Base Station] arrangements
• CPC Class Codes: H04W 48/12 using downlink control channel
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A method and apparatus in a wireless communications system enables a beacon to be leap-frogged. The system includes at least one radio fixed part (RFP) that is in radio communication with multiple portable parts (PP). According to the present invention, the RFP is originally broadcasting with an old beacon. Prior to the expiration of a maximum continuous broadcast period, the RFP determines an appropriate channel for a new beacon. The new beacon must be on a different carrier from that of the old beacon. Furthermore, the RFP must comply with the listening before talking and least interfering channel protocols. The RFP may then begin broadcasting with the new beacon. Prior to terminating the old beacon, the RFP informs associated PPs of the location of the new beacon in a system information broadcast on the old beacon. The old beacon is then terminated within the maximum continuous broadcast period.

Claims

1. A method in a wireless communications system for relocating a beacon in a known manner, comprising the steps of:

originating a first broadcasting of beacon information on a first channel;

broadcasting a location of a second channel for directing at least one mobile station to switch from said first channel to said second channel on said first channel;

originating a second broadcasting of beacon information on said second channel;

receiving, by the at least one mobile station, of the location of said second channel on said first channel;

responsive to said step of receiving, switching by said at least one mobile station from said first channel to said second channel; and

terminating the first broadcasting of beacon information on said first channel after the second broadcasting of beacon information on said second channel has originated.

2. The method according to claim 1, wherein said step of broadcasting a location of a second channel further comprises:

determining whether a test channel has a signal above a predetermined threshold; and

selecting said test channel as said second channel if said test channel does not have said signal above said predetermined threshold.

3. The method according to claim 1, wherein said step of broadcasting a location of a second channel further comprises:

determining a test channel having a lowest power level below a predetermined threshold; and

selecting said test channel as said second channel.

4. The method according to claim 1, wherein said step of broadcasting a location of a second channel further comprises:

ascertaining a first carrier frequency of said first channel;

determining a second carrier frequency that differs from said first carrier frequency; and

selecting said second carrier frequency for said second channel.

5. The method according to claim 1, further comprising the step of:

waiting at least a predetermined period of time between said step of originating a second broadcasting of beacon information on said second channel and said step of terminating the first broadcasting of beacon information on said first channel.

6. The method according to claim 5, wherein said step of waiting at least a predetermined period of time further comprises the step of:

waiting at least approximately 1280 milliseconds between said step of originating a second broadcasting of beacon information on said second channel and said step of terminating the first broadcasting of beacon information on said first channel.

7. The method according to claim 1, further comprising the step of:

waiting no more than a predetermined period of time between said step of originating a first broadcasting of beacon information on a first channel and said step of terminating the first broadcasting of beacon information on said first channel.

8. The method according to claim 7, wherein said step of waiting no more than a predetermined period of time further comprises the step of:

waiting no more than approximately 30 seconds between said step of originating a first broadcasting of beacon information on a first channel and said step of terminating the first broadcasting of beacon information on said first channel.

9. The method according to claim 1, wherein the first and second broadcasting of beacon information further include broadcasting control and signaling information for said wireless communications system.

10. The method according to claim 1, wherein said step of broadcasting a location of a second channel on said first channel further comprises the step of:

broadcasting a carrier frequency and a time slot of said second channel.

11. The method according to claim 1, wherein said step of broadcasting a location of a second channel on said first channel further comprises the step of:

broadcasting a location of said second channel in a system information broadcast.

12. The method according to claim 1, further comprising the step of:

repeating, at periodic intervals, the steps of originating a first broadcasting, broadcasting a location, originating a second broadcasting, and terminating the first broadcasting.

13. The method according to claim 1, wherein said steps are performed in the order listed.

14. A wireless communications system that employs a broadcast beacon that leapfrog-hops over a plurality of channels, said system comprising:

a base station that relocates said broadcast beacon from a first channel to a second channel of the plurality of channels at periodic intervals, wherein said base station broadcasts on said first channel a location of said second channel for directing mobile terminals from said first channel to said second channel and originates broadcasting of said beacon on said second channel before terminating said beacon on said first channel; and

a plurality of mobile terminals that are in communication with said base station, said plurality of mobile terminals locking onto said broadcast beacon on said second channel in response to receipt on said first channel of said location of said second channel as said broadcast beacon is relocated from said first channel to said second channel, wherein said second channel is known to said plurality of mobile terminals.

15. The wireless communications system of claim 14, wherein said plurality of mobile terminals lock onto said broadcast beacon without scanning said plurality of channels.

16. The wireless communications system of claim 14, wherein said periodic intervals are approximately 30 seconds.

17. The wireless communications system of claim 14, wherein said base station broadcasts a location of a successor broadcast beacon on a predecessor broadcast beacon.

18. The wireless communications system of claim 17, wherein said location includes a carrier frequency and a time slot.

19. The wireless communications system of claim 17, wherein a first carrier frequency of said predecessor broadcast beacon differs from a second carrier frequency of said successor broadcast beacon.

20. The wireless communications system of claim 17, wherein said base station broadcasts both said successor broadcast beacon and said predecessor broadcast beacon simultaneously for at least a predetermined period of time.

21. The wireless communications system of claim 20, wherein said predetermined period of time is approximately 1280 milliseconds.

22. The wireless communications system of claim 14, wherein said broadcast beacon broadcasts control and signaling information for said wireless communications system.

23. The wireless communications system of claim 14, wherein said base station performs access criteria functions before relocating said broadcast beacon.

24. A method in a wireless communications system for relocating a beacon in a known manner, comprising the steps of:

originating a first broadcasting of beacon information on a first channel having a first carrier frequency;

broadcasting a location of a second channel for directing at least one mobile terminal to switch from said first channel to said second channel on said first channel, said second channel having a second carrier frequency, and wherein said first and second carrier frequencies are unequal;

originating a second broadcasting of beacon information on said second channel;

receiving, by the at least one mobile terminal, of the location of said second channel on said first channel;

responsive to said step of receiving, switching by said at least one mobile terminal from said first channel to said second channel;

terminating the first broadcasting of beacon information on said first channel after the second broadcasting of beacon information on said second channel has originated;

waiting no more than a predetermined period of time between said step of originating a first broadcasting of beacon information on a first channel and said step of terminating the first broadcasting of beacon information on said first channel; and

repeating, periodically, the steps of originating a first broadcasting, broadcasting a location, originating a second broadcasting, terminating the first broadcasting, and waiting no more than a predetermined period of time.

25. The method according to claim 24, wherein said step of broadcasting a location of a second channel on said first channel further comprises the step of:

broadcasting said second carrier frequency and a time slot of said second channel.

26. The method according to claim 24, further comprising the steps of:

receiving said first broadcasting of beacon information on said first channel;

receiving said location of said second channel on said first channel; and

switching reception from said first broadcasting of beacon information on said first channel to said second broadcasting of beacon information on said second channel.

27. The method according to claim 26, wherein said step of receiving said first broadcasting of beacon information on said first channel further comprises the step of:

receiving said beacon information in a system information broadcast.

28. The method according to claim 24, wherein the first and second broadcasting of beacon information further include broadcasting control and signaling information for said wireless communications system.

29. The method according to claim 24, further comprising the step of:

waiting at least a second predetermined period of time between said step of originating a second broadcasting of beacon information on said second channel and said step of terminating the first broadcasting of beacon information on said first channel.

30. The method of claim 24, wherein said steps are performed in the order listed.

31. A wireless communications system for relocating a beacon in a known manner, comprising:

means for originating a first broadcasting of beacon information on a first channel;

means for broadcasting a location of a second channel for directing at least one mobile station to switch from said first channel to said second channel on said first channel;

means for originating a second broadcasting of beacon information on said second channel;

means for receiving, by the at least one mobile station, of the location of said second channel on said first channel;

means for switching, responsive to receipt of said location of said second channel, of said at least one mobile station from said first channel to said second channel; and

means for terminating the first broadcasting of beacon information on said first channel after the second broadcasting of beacon information on said second channel has originated.

32. The system according to claim 31, wherein said means for broadcasting of said location of a second channel further comprises:

means for determining whether a test channel has a signal above a predetermined threshold; and

means for selecting said test channel as said second channel if said test channel does not have said signal above said predetermined threshold.

33. The system according to claim 31, wherein said means for broadcasting said location of said second channel further comprises:

means for determining a test channel having a lowest power level below a predetermined threshold; and

means for selecting said test channel as said second channel.

34. The system according to claim 31, wherein said means for broadcasting said location of said second channel further comprises:

means for ascertaining a first carrier frequency of said first channel;

means for determining a second carrier frequency that differs from said first carrier frequency; and

means for selecting said second carrier frequency for said second channel.

35. The system according to claim 31, further comprising:

means for waiting at least a predetermined period of time between origination of a second broadcasting of beacon information on said second channel and termination of the first broadcasting of beacon information on said first channel.

36. The system according to claim 35, wherein said means for waiting at least a predetermined period of time further comprises:

means for waiting at least approximately 1280 milliseconds between origination of a second broadcasting of beacon information on said second channel and termination of the first broadcasting of beacon information on said first channel.

37. The system according to claim 31, further comprising:

means for waiting no more than a predetermined period of time between origination of a first broadcasting of beacon information on a first channel and termination of the first broadcasting of beacon information on said first channel.

38. The system according to claim 37, wherein said means for waiting no more than a predetermined period of time further comprises:

means for waiting no more than approximately 30 seconds between origination of a first broadcasting of beacon information on a first channel and termination of the first broadcasting of beacon information on said first channel.

39. The system according to claim 31, wherein the first and second means for broadcasting of beacon information further include means for broadcasting control and signaling information for said wireless communications system.

40. The system according to claim 31, wherein said means for broadcasting a location of a second channel on said first channel further comprises:

means for broadcasting a carrier frequency and a time slot of said second channel.

41. The system according to claim 31, wherein said means for broadcasting a location of a second channel on said first channel further comprises:

means for broadcasting a location of said second channel in a system information broadcast.

42. The system according to claim 31, further comprising:

means for repeating, at periodic intervals, origination of a first broadcast, broadcast of a location, origination of a second broadcast, and termination of the first broadcast.