Use of pre-handoff macro-carrier data for prioritization of carriers in femtocell frequency-hopping pilot beacons

• US 9,107,148 B1
• Filed: 11/30/2009
• Issued: 08/11/2015
• Est. Priority Date: 11/30/2009
• Status: Active Grant

• Current Assignee: Sprint Spectrum LLC (Deutsche Telekom AG)
• Original Assignee: Sprint Spectrum LP (Deutsche Telekom AG)
• Inventors: Malreddy, Muralidhar, Talley, Ryan, Narendran, Rajveen
• Primary Examiner(s): Balaoing, Ariel
• Application Number:
  US12/627,758
• Time in Patent Office: 2,080 Days
• Field of Search: 455/421, 455/425, 455/434, 455/436, 455/448, 455/449, 455/443, 455/444, 370/328, 370/331, 370/338
• US Class Current: 1/1
• CPC Class Codes: H04B 1/713 using frequency hopping
• CPC Class Codes: H04L 5/0012 Hopping in multicarrier systems for frequency hopping in spread spectrum systems H04B1/713
• CPC Class Codes: H04L 5/0073 Allocation arrangements that take into account other cell interferences for intercell interference mitigation or co-ordination in orthogonal multiplex systems H04J11/005
• CPC Class Codes: H04W 48/12 using downlink control channel
• CPC Class Codes: H04W 48/20 Selecting an access point
• CPC Class Codes: H04W 84/045 using private Base Stations, e.g. femto Base Stations, home Node B

Abstract

Methods and systems are provided for prioritizing carriers in femtocell frequency-hopping pilot beacons. A femtocell receives registration requests from a number of mobile devices requesting to hand off service from a macro-network carrier to the femtocell. The femtocell identifies the macro-network carrier that each mobile device has handed off from. The femtocell then uses that information to prioritize future broadcasts of its frequency-hopping pilot beacon on those macro-network carriers on which the most mobile devices have handed off from. The prioritization could take the form of broadcasting more often on the higher priority one or more carriers per cycle, or broadcasting for a longer continuous period of time on the higher priority one or more carriers per cycle.

Claims

1. A method for a femtocell to prioritize at least one carrier for a frequency-hopping pilot beacon, the method comprising:

a femtocell transmitting a frequency-hopping pilot beacon, wherein transmitting a frequency-hopping pilot beacon comprises repeatedly cycling through transmitting pilot-beacon information on each of multiple macro-network carriers;

the femtocell receiving registration requests from mobile devices each requesting to hand off service to the femtocell from one of the multiple macro-network carriers, and responsively providing service to the mobile devices;

the femtocell identifying the macro-network carriers on which the mobile devices were receiving service prior to handing off to the femtocell, including identifying a first macro-network carrier as the macro-network carrier on which the highest number of the mobile devices were receiving service prior to handing off to the femtocell; and

based at least in part on the identifying step, prioritizing at least the identified first macro-network carrier with respect to a total amount of transmission time in at least one subsequent cycle of the frequency-hopping pilot beacon.

2. The method of claim 1, wherein the frequency-hopping pilot beacon comprises a pilot channel, a paging channel, and a sync channel.

3. The method of claim 1, further comprising:

the femtocell maintaining a list identifying the macro-network carrier on which each mobile device was receiving service prior to handing off service to the femtocell,

wherein the identifying the first macro-network carrier comprises sorting the list based on the number of mobile devices that were receiving service on each macro-network carrier prior to handing off service to the femtocell.

4. The method of claim 1, wherein the femtocell prioritizes the first macro-network carrier by transmitting the frequency-hopping pilot beacon on the first macro-network carrier more than once in the at least one subsequent cycle of the frequency hopping pilot beacon.

5. The method of claim 1, wherein the femtocell prioritizes the first macro-network carrier by transmitting the frequency-hopping pilot beacon on the first macro-network carrier for a longer first continuous period of time compared to one or more shorter continuous periods of time during which the femtocell transmits the frequency-hopping pilot beacon on each of macro-network carriers other than the first macro-network carrier.

6. The method of claim 1, wherein the femtocell identifying the macro-network carrier on which a given mobile device was receiving service prior to handing off to the femtocell comprises the femtocell identifying the macro-network carrier on which the femtocell is currently broadcasting the frequency-hopping pilot beacon at the time the femtocell receives a registration message from the given mobile device.

7. The method of claim 1, wherein the femtocell identifying the macro-network carrier on which a given mobile device was receiving service prior to handing off to the femtocell comprises the femtocell identifying the macro-network carrier on which the femtocell was broadcasting the frequency-hopping pilot beacon a fixed period of time prior to receiving a registration message from the given mobile device.

8. The method of claim 7, wherein the femtocell maintains a history of the last “

n”

macro-network carriers on which the femtocell has broadcasted the frequency-hopping pilot beacon, where 1<

n, and identifies the macro-network carrier on which the femtocell was broadcasting the frequency-hopping pilot beacon a fixed period of time prior to receiving a registration message from the given mobile device by referencing the history.

9. The method of claim 1, wherein the femtocell identifying the macro-network carrier on which a given mobile device was receiving service prior to handing off to the femtocell comprises the femtocell receiving a message from the given mobile device identifying the macro-network carrier on which the given mobile device was receiving service prior to handing off service to the femtocell.

10. The method of claim 9, wherein the message also includes a request for service from the femtocell.

11. A femtocell comprising:

a communication interface;

a processor; and

data storage comprising instructions executable by the processor to;

transmit a frequency-hopping pilot beacon by repeatedly cycling through transmitting pilot-beacon information on each of multiple macro-network carriers;

receive registration requests from mobile devices each requesting to hand off service to the femtocell from one of the multiple macro-network carriers, and responsively providing service to the mobile devices;

identify the macro-network carriers on which the mobile devices were receiving service prior to handing off to the femtocell, including identifying a first macro-network carrier as the macro-network carrier on which the highest number of the mobile devices were receiving service prior to handing off to the femtocell; and

prioritize at least the identified first macro-network carrier with respect to a total amount of transmission time in at least one subsequent cycle of the frequency-hopping pilot beacon.

12. The femtocell of claim 11, wherein the frequency-hopping pilot beacon comprises a pilot channel, a paging channel, and a sync channel.

13. The femtocell of claim 11, wherein the data storage further comprises instructions executable by the processor to maintain a list identifying the macro-network carrier on which each mobile device was receiving service prior to handing off service to the femtocell, and

wherein the identifying a first macro-network carrier comprises sorting the list based on the number of mobile devices that were receiving service on each macro-network carrier prior to handing off service to the femtocell.

14. The femtocell of claim 11, wherein the data storage further comprises instructions executable by the processor to prioritize the first macro-network carrier by transmitting the frequency-hopping pilot beacon on the first macro-network carrier more than once in the at least one subsequent cycle of the frequency-hopping pilot beacon.

15. The femtocell of claim 11, wherein the data storage further comprises instructions executable by the processor to prioritize the first macro-network carrier by transmitting the frequency-hopping pilot beacon on the first macro-network carrier for a longer first continuous period of time compared to one or more shorter continuous periods of time during which the femtocell transmits the frequency-hopping pilot beacon on each of macro-network carriers other than the first macro-network carrier.

16. The femtocell of claim 11, wherein the instructions to identify the macro-network carrier on which a given mobile device was receiving service prior to handing off to the femtocell comprise instructions to identify the macro-network carrier on which the femtocell is currently broadcasting the frequency-hopping pilot beacon at the time the femtocell receives a registration message from the given mobile device.

17. The femtocell of claim 11, wherein the instructions to identify the macro-network carrier on which a given mobile device was receiving service prior to handing off to the femtocell comprise instructions to identify the macro-network carrier on which the femtocell was broadcasting the frequency-hopping pilot beacon a fixed period of time prior to receiving a registration message from the given mobile device.

18. The femtocell of claim 17, wherein femtocell maintains a history of the last “

n”

macro-network carriers on which the femtocell has broadcasted the frequency-hopping pilot beacon, where 1<

n, and identifies the macro-network carrier on which the femtocell was broadcasting the frequency-hopping pilot beacon a fixed period of time prior to receiving a registration message from the given mobile device by referencing the history.

19. The femtocell of claim 11, wherein the instructions to identify the macro-network carrier on which a given mobile device was receiving service prior to handing off to the femtocell comprise instructions to receive and process a message from the given mobile device identifying the macro-network carrier on which the given mobile device was receiving service prior to handing off service to the femtocell.

20. The femtocell of claim 19, wherein the message also includes a request for service from the femtocell.