Methods and systems for using femtocells to address macro-network backhaul congestion

• US 8,103,310 B1
• Filed: 08/07/2009
• Issued: 01/24/2012
• Est. Priority Date: 08/07/2009
• Status: Active Grant

• Current Assignee: Sprint Spectrum LP (Deutsche Telekom AG)
• Original Assignee: Sprint Spectrum LP (Deutsche Telekom AG)
• Inventors: Srinivas, Shilpa Kowdley, Goyal, Anoop K., Khanka, Bhagwan, Prock, John W., Pawar, Hemanth Balaji
• Primary Examiner(s): LE, NHAN T
• Application Number:
  US12/537,740
• Time in Patent Office: 900 Days
• Field of Search: 455/450, 455/452.2, 455/561, 370/329
• US Class Current: 455/561
• CPC Class Codes: H04W 28/0247 based on conditions of the access network or the infrastructure network central resource management H04W28/16
• CPC Class Codes: H04W 36/22 for handling the traffic
• CPC Class Codes: H04W 84/045 using private Base Stations, e.g. femto Base Stations, home Node B
• CPC Class Codes: H04W 88/08 Access point devices
• CPC Class Codes: H04W 88/12 Access point controller devices
• CPC Class Codes: H04W 92/12 between access points and access point controllers

Abstract

Methods and systems are provided for using femtocells to address macro-network backhaul congestion. In an embodiment, a macro base transceiver station (BTS) that has a backhaul connection to a radio network controller (RNC) detects that a current utilization of the backhaul exceeds a backhaul-congestion threshold, and responsively identifies one or more sector-carriers having a respective current air-interface utilization that is less than a respective sector-carrier-congestion threshold for the respective sector-carrier. The macro BTS further identifies one or more femtocells that are positioned in the coverage area of the one or more identified sector-carriers, and offloads some reverse-link traffic to each identified femtocell over the forward link of an identified sector-carrier in whose coverage area the respective identified femtocell is positioned, for forwarding of the offloaded traffic by the one or more identified femtocells over a packet-data network to an intended destination.

Claims

1. A method comprising:

a macro base transceiver station (BTS) that has a backhaul connection to a radio network controller (RNC) and provides service to access terminals on a plurality of sector-carriers, each sector-carrier having a respective coverage area, detecting that a current utilization of the backhaul connection exceeds a backhaul-congestion threshold;

responsive to detecting that the current utilization of the backhaul connection exceeds the backhaul-congestion threshold, the macro BTS identifying one or more of the sector-carriers in the plurality of sector-carriers having a respective current air-interface utilization that is less than a respective sector-carrier-congestion threshold for the respective sector-carrier;

the macro BTS identifying one or more femtocells that are positioned in the coverage area of the one or more identified sector-carriers; and

the macro BTS offloading some reverse-link traffic to each identified femtocell over a forward link of an identified sector-carrier in whose coverage area the respective identified femtocell is positioned, for forwarding of the offloaded traffic by the one or more identified femtocells over a packet-data network to an intended destination of the offloaded traffic.

2. The method of claim 1, wherein the backhaul connection comprises a T1 line.

3. The method of claim 1, wherein the service comprises EV-DO (Evolution Data Optimized) service in compliance with at least one of IS-856, Release 0 and IS-856, Revision A.

4. The method of claim 1, wherein the macro BTS provides service in a plurality of sectors, each sector associated with at least one sector-carrier in the plurality of sector-carriers.

5. The method of claim 1, wherein the backhaul-congestion threshold is about 90%.

6. The method of claim 1, wherein at least one sector-carrier-congestion threshold is about 75%.

7. The method of claim 1, wherein the same sector-carrier-congestion threshold is used for every sector-carrier in the plurality.

8. The method of claim 1, wherein the same sector-carrier-congestion threshold is not used for every sector-carrier in the plurality.

9. The method of claim 1, wherein each identified femtocell comprises a respective receiver, the method further comprising the macro BTS directing each identified femtocell to tune its respective receiver to an identified sector-carrier in whose coverage area the respective identified femtocell is positioned.

10. The method of claim 1, further comprising the macro BTS directing each identified femtocell to forward the offloaded traffic over the packet-data network to the intended destination of the offloaded traffic.

11. The method of claim 1, wherein identifying one or more femtocells that are positioned in the coverage area of the one or more identified sector-carriers comprises identifying one or more femtocells that are (1) positioned in the coverage area of the one or more identified sector-carriers and (2) requesting a forward-link data rate that exceeds a forward-link-data-rate threshold.

12. The method of claim 1, wherein identifying one or more femtocells that are positioned in the coverage area of the one or more identified sector-carriers comprises identifying one or more femtocells that are (1) positioned in the coverage area of the one or more identified sector-carriers and (2) currently bearing an amount of data that is less than a data-bearing threshold.

13. The method of claim 1, wherein the macro BTS offloads traffic to exactly one femtocell.

14. The method of claim 1, wherein the macro BTS identifies offloads traffic to multiple femtocells.

15. The method of claim 1, wherein the offloaded traffic does not comprise latency-sensitive traffic, wherein the macro BTS sends latency-sensitive traffic from all sector-carriers in the plurality of sector-carriers to the RNC over the backhaul connection.

16. The method of claim 1, wherein the offloaded traffic does not comprise traffic received on sector-carriers having a respective current air-interface utilization that is greater than a respective sector-carrier-congestion threshold for the respective sector-carrier, wherein the macro BTS sends such traffic to the RNC over the backhaul connection.

17. The method of claim 1, wherein the offloaded traffic comprises traffic that is both (1) latency-tolerant and (2) received on sector-carriers having a respective current air-interface utilization that is less than a respective sector-carrier-congestion threshold for the respective sector-carrier.

18. The method of claim 1, wherein the offloaded traffic consists of traffic that is both (1) latency-tolerant and (2) received on sector-carriers having a respective current air-interface utilization that is less than a respective sector-carrier-congestion threshold for the respective sector-carrier.

19. The method of claim 1, wherein the offloaded traffic comprises traffic that is both latency-tolerant and error-intolerant.

20. The method of claim 1, wherein the offloaded traffic consists of traffic that is both latency-tolerant and error-intolerant.

21. The method of claim 1, wherein the packet-data network comprises the Internet.

22. The method of claim 1, further comprising the one or more identified femtocells forwarding the offloaded traffic over the packet-data network to the intended destination of the offloaded traffic.

23. The method of claim 1, further comprising the macro BTS ceasing the use of a given femtocell for offloading of traffic in response to determining that the given femtocell has begun serving an access terminal.

24. A macro base transceiver station (BTS), wherein the macro BTS provides service on a plurality of sector-carriers, each sector-carrier having a respective coverage area, the macro BTS comprising:

a backhaul connection to a radio network controller (RNC);

a communication interface;

a processor; and

data storage comprising instructions executable by the processor for;

detecting that a current utilization of the backhaul connection exceeds a backhaul-congestion threshold;

responsive to detecting that the current utilization of the backhaul connection exceeds the backhaul-congestion threshold, identifying one or more of the sector-carriers in the plurality of sector-carriers having a respective current air-interface utilization that is less than a respective sector-carrier-congestion threshold for the respective sector-carrier;

identifying one or more femtocells that are positioned in the coverage area of the one or more identified sector-carriers; and

offloading some reverse-link traffic to each identified femtocell over a forward link of an identified sector-carrier in whose coverage area the respective identified femtocell is positioned, for forwarding of the offloaded traffic by the one or more identified femtocells over a packet-data network to an intended destination of the offloaded traffic.

25. A method comprising:

a radio network controller (RNC) that has a backhaul connection to a macro base transceiver station (BTS) that provides service on a plurality of sector-carriers, each sector-carrier having a respective coverage area, detecting that a current utilization of the backhaul connection exceeds a backhaul-congestion threshold;

responsive to detecting that the current utilization of the backhaul connection exceeds the backhaul-congestion threshold, the RNC identifying one or more of the sector-carriers in the plurality of sector-carriers having a respective current air-interface utilization that is less than a respective sector-carrier-congestion threshold for the respective sector-carrier;

the RNC identifying one or more femtocells that are positioned in the coverage area of the one or more identified sector-carriers; and

the RNC offloading some forward-link traffic to each identified femtocell over a packet-data network, for forwarding of the offloaded traffic by the one or more identified femtocells to the macro BTS over a reverse link of an identified sector-carrier in whose coverage area the respective identified femtocell is positioned, for forwarding of the offloaded traffic by the macro BTS over a forward link of at least one sector-carrier to one or more access terminals.