Methods and Apparatus of Improving Inter-Sector and/or Inter Cell Handoffs In a Multi-Carrier Wireless Communications System

• US 20100210266A1
• Filed: 01/20/2010
• Published: 08/19/2010
• Est. Priority Date: 10/16/2003
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Lane, Frank A., Laroia, Rajiv
• Granted Patent: US 8,428,594 B2
• Time in Patent Office: Days
• US Class Current: 455/436
• CPC Class Codes: H04L 27/2602 Signal structure
• CPC Class Codes: H04L 5/0042 intra-user or intra-terminal allocation
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04W 36/0072 of resource information of target access point
• CPC Class Codes: H04W 36/08 Reselecting an access point

Abstract

A wireless communications system, e.g., an OFDM system, uses a plurality of carrier frequencies each with an associated frequency band. A base station sector transmitter in the system transmits ordinary signaling, e.g., user data, in its own assigned band. In addition the sector base station transmitter periodically transmits beacon signals into its own frequency band and the frequency bands used by adjacent sector transmitters for their ordinary signaling. Beacon signals, being short duration high power signals with sector transmission power concentrated on one or a few tones, are easily detectable. Each beacon signal may be identified as to the source base station sector transmitter, e.g., based on tone. A mobile node, tuned to a single carrier band, receives a plurality of beacon signals, identifies the sources of the received beacons, compares the received strength of the beacons, and makes handoff decisions, without having to switch carrier band.

Claims

1. A wireless terminal, comprising:

means for receiving ordinary signaling that is transmitted by a first base station transmitter; and

means for receiving a beacon signal that is transmitted by a second base station transmitter;

wherein the wireless terminal receives both the ordinary signaling and the beacon signal without switching between different frequency bands.

2. The wireless terminal of claim 1, wherein the ordinary signaling comprises user data and control information.

3. The wireless terminal of claim 1, wherein the beacon signal comprises higher power than the ordinary signaling.

4. The wireless terminal of claim 1, wherein the first base station transmitter transmits the ordinary signaling to a first sector that comprises the wireless terminal, wherein the second base station transmitter transmits its ordinary signaling to a second sector, and wherein the first sector is adjacent to the second sector.

5. The wireless terminal of claim 4, wherein the first sector is located within a cell, and wherein the second sector is located within the same cell.

6. The wireless terminal of claim 4, wherein the first sector is located within a first cell, and wherein the second sector is located within a second cell.

7. The wireless terminal of claim 1, further comprising means for receiving a beacon signal that is transmitted by the first base station transmitter.

8. The wireless terminal of claim 7, further comprising:

means for comparing the strength of the beacon signal that is transmitted by the first base station transmitter with the strength of the beacon signal that is transmitted by the second base station transmitter; and

means for determining whether a handoff should be initiated based on the comparison.

9. An apparatus, comprising:

means for causing a base station transmitter to transmit ordinary signaling into a first frequency band during a first period of time, wherein the base station transmitter does not transmit into a second frequency band during the first period of time; and

means for causing the base station transmitter to transmit a beacon signal into the second frequency band during a second period of time that is shorter than the first period of time, wherein the beacon signal is transmitted at higher power than the ordinary signaling.

10. The apparatus of claim 9, wherein the base station transmitter does not transmit into the first frequency band during the second period of time.

11. A wireless terminal, comprising:

circuitry configured to receive ordinary signaling that is transmitted by a first base station transmitter and to receive a beacon signal that is transmitted by a second base station transmitter;

wherein the wireless terminal receives both the ordinary signaling and the beacon signal without switching between different frequency bands.

12. The wireless terminal of claim 11, wherein the ordinary signaling comprises user data and control information.

13. The wireless terminal of claim 11, wherein the beacon signal comprises higher power than the ordinary signaling.

14. The wireless terminal of claim 11, wherein the first base station transmitter transmits the ordinary signaling to a first sector that comprises the wireless terminal, wherein the second base station transmitter transmits its ordinary signaling to a second sector, and wherein the first sector is adjacent to the second sector.

15. The wireless terminal of claim 14, wherein the first sector is located within a cell, and wherein the second sector is located within the same cell.

16. The wireless terminal of claim 14, wherein the first sector is located within a first cell, and wherein the second sector is located within a second cell.

17. The wireless terminal of claim 11, wherein the circuitry is also configured to receive a beacon signal that is transmitted by the first base station transmitter.

18. The wireless terminal of claim 17, wherein the circuitry is also configured to:

compare the strength of the beacon signal that is transmitted by the first base station transmitter with the strength of the beacon signal that is transmitted by the second base station transmitter; and

determine whether a handoff should be initiated based on the comparison.

19. An apparatus, comprising:

circuitry configured to cause a base station transmitter to;

transmit ordinary signaling into a first frequency band during a first period of time, wherein the base station transmitter does not transmit into a second frequency band during the first period of time; and

transmit a beacon signal into the second frequency band during a second period of time that is shorter than the first period of time, wherein the beacon signal is transmitted at higher power than the ordinary signaling.

20. The apparatus of claim 19, wherein during the second period of time the base station transmitter does not transmit into the first frequency band.

21. A method, comprising:

a wireless terminal receiving ordinary signaling that is transmitted by a first base station transmitter; and

the wireless terminal receiving a beacon signal that is transmitted by a second base station transmitter;

wherein the wireless terminal receives both the ordinary signaling and the beacon signal without switching between different frequency bands.

22. The method of claim 21, wherein the ordinary signaling comprises user data and control information.

23. The method of claim 21, wherein the beacon signal comprises higher power than the ordinary signaling.

24. The method of claim 21, wherein the first base station transmitter transmits the ordinary signaling to a first sector that comprises the wireless terminal, wherein the second base station transmitter transmits its ordinary signaling to a second sector, and wherein the first sector is adjacent to the second sector.

25. The method of claim 24, wherein the first sector is located within a cell, and wherein the second sector is located within the same cell.

26. The method of claim 24, wherein the first sector is located within a first cell, and wherein the second sector is located within a second cell.

27. The method of claim 21, further comprising the wireless terminal receiving a beacon signal that is transmitted by the first base station transmitter.

28. The method of claim 27, further comprising:

the wireless terminal comparing the strength of the beacon signal that is transmitted by the first base station transmitter with the strength of the beacon signal that is transmitted by the second base station transmitter; and

the wireless terminal determining whether a handoff should be initiated based on the comparison.

29. A method, comprising:

a base station transmitter transmitting ordinary signaling into a first frequency band during a first period of time, wherein the base station transmitter does not transmit into a second frequency band during the first period of time; and

the base station transmitter transmitting a beacon signal into the second frequency band during a second period of time that is shorter than the first period of time, wherein the beacon signal is transmitted at higher power than the ordinary signaling.

30. The method of claim 29, wherein the base station transmitter does not transmit into the first frequency band during the second period of time.

31. A computer-program product comprising a computer-readable medium having instructions thereon, the instructions comprising:

code for causing a wireless terminal to receive ordinary signaling that is transmitted by a first base station transmitter; and

code for causing the wireless terminal to receive a beacon signal that is transmitted by a second base station transmitter;

wherein the wireless terminal receives both the ordinary signaling and the beacon signal without switching between different frequency bands.

32. The computer-program product of claim 31, wherein the ordinary signaling comprises user data and control information.

33. The computer-program product of claim 31, wherein the beacon signal comprises higher power than the ordinary signaling.

34. The computer-program product of claim 31, wherein the first base station transmitter transmits the ordinary signaling to a first sector that comprises the wireless terminal, wherein the second base station transmitter transmits its ordinary signaling to a second sector, and wherein the first sector is adjacent to the second sector.

35. The computer-program product of claim 34, wherein the first sector is located within a cell, and wherein the second sector is located within the same cell.

36. The computer-program product of claim 34, wherein the first sector is located within a first cell, and wherein the second sector is located within a second cell.

37. The computer-program product of claim 31, wherein the instructions further comprise code for receiving a beacon signal that is transmitted by the first base station transmitter.

38. The computer-program product of claim 37, wherein the instructions further comprise:

code for comparing the strength of the beacon signal that is transmitted by the first base station transmitter with the strength of the beacon signal that is transmitted by the second base station transmitter; and

code for determining whether a handoff should be initiated based on the comparison.

39. A computer-program product comprising a computer-readable medium having instructions thereon, the instructions comprising:

code for causing a base station transmitter to transmit ordinary signaling into a first frequency band during a first period of time, wherein the base station transmitter does not transmit into a second frequency band during the first period of time; and

code for causing the base station transmitter to transmit a beacon signal into the second frequency band during a second period of time that is shorter than the first period of time, wherein the beacon signal is transmitted at higher power than the ordinary signaling.

40. The computer-program product of claim 39, wherein the base station transmitter does not transmit into the first frequency band during the second period of time.