Methods and apparatus for beamforming for femtocells

• US 8,831,523 B2
• Filed: 06/17/2010
• Issued: 09/09/2014
• Est. Priority Date: 06/18/2009
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Damnjanovic, Aleksandar, Gorokhov, Alexei Yurievitch
• Primary Examiner(s): Eisner, Ronald
• Application Number:
  US12/818,054
• Publication Number:
  US 20100323711A1
• Time in Patent Office: 1,545 Days
• Field of Search: 455418-420, 455436-444, 4554321-433, 455/63.1, 455/63.4, 455/63.2, 455/82, 455/83, 455/562.1, 455/575.7, 455418-420, 4554321-434, 4554351-4353, 455/422.1, 455450-455, 455/464, 455/509, 455/410, 455/411, 370/338, 370/339, 370328-337, 370341-348, 370431-463
• US Class Current: 455/63.2
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0626 Channel coefficients, e.g. channel state information [CSI]
• CPC Class Codes: H04J 11/0053 using co-ordinated multipoint transmission/reception co-ordinated antenna or beam-forming aspects H04B7/022
• CPC Class Codes: H04L 25/03821 Inter-carrier interference cancellation [ICI]
• CPC Class Codes: H04W 24/02 Arrangements for optimising operational condition
• CPC Class Codes: H04W 52/18 TPC being performed according to specific parameters
• CPC Class Codes: H04W 72/046 the resource being in the space domain, e.g. beams
• CPC Class Codes: H04W 72/541 using the level of interference
• CPC Class Codes: H04W 84/045 using private Base Stations, e.g. femto Base Stations, home Node B

Abstract

Methods and apparatus for beamforming for femtocells, such as in LTE wireless networks, to provide inter-cell coordination and interference mitigation are disclosed. A macrocell user equipment (UE) may determine information regarding an interfering femtocell node, such as a home eNodeB (HeNB). The information may be sent directly or indirectly, such as by a backhaul communication link, to the HeNB. The HeNB may adjust an output based on the information. The information may include spatial channel information, which may be used for beamforming at the HeNB output so as to mitigate interference in the direction of the UE.

Claims

1. A method for wireless communication, comprising:

detecting, at a user device, a signal transmitted by a restricted wireless network node which the user device is not subscribed to;

determining, by the user device, from the signal, information regarding the restricted wireless network node;

transmitting the information from the user device to the restricted wireless network node in order to cause the restricted wireless network node to adjust the signal transmitted in a direction of the user device to avoid or reduce interference at the user device; and

establishing, by the user device, a connection with a serving node subsequent to the adjustment of the signal transmitted in the direction of the user device.

2. The method of claim 1 wherein the information includes spatial channel information.

3. The method of claim 2 wherein the information further includes signal strength information.

4. The method of claim 1 wherein the serving node comprises a macrocell node.

5. The method of claim 4 wherein the restricted wireless network node comprises a femtocell node.

6. A non-transitory computer program product comprising a non-transitory computer-readable medium, the computer-readable medium including codes for causing a computer to:

detect, at a user device, a signal transmitted by a restricted wireless network node which the user device is not subscribed to;

determine, at the user device, from the signal, information regarding the restricted wireless network node;

transmit the information from the user device to the restricted wireless network node in order to cause the restricted wireless network node to adjust the signal transmitted in a direction of the user device to avoid or reduce interference at the user device; and

establishing, by the user device, a connection with a serving node subsequent to the adjustment of the signal transmitted in the direction of the user device.

7. A user device, comprising:

a receiver module configured to receive signals from a restricted wireless network node, to which the user device does not subscribe;

a signal information module of the user device, the signal information module configured to determine, from one of the signals received from the restricted wireless network node, information regarding the restricted wireless network node;

a transmitter module of the user device, the transmitter module configured to send the information to the restricted wireless network node in order to cause the restricted wireless network node to adjust the signal transmitted in the direction of the user device to avoid or reduce interference at the user device; and

establish a connection with a serving node subsequent to the adjustment of the signal transmitted in the direction of the user device.

8. The device of claim 7 wherein the information includes spatial channel information.

9. The device of claim 8 wherein the information further includes signal strength information.

10. The device of claim 9 wherein the serving node comprises a macrocell node.

11. The device of claim 10 wherein the restricted wireless network node comprises a femtocell node.

12. A user device, comprising:

means for receiving signals at the user device, with which the user device is associated, and a restricted wireless network node, to which the user device does not subscribe;

means for determining, by the user device, from a signal received from the restricted wireless network node, information regarding the restricted wireless network node;

means for sending the information from the user device to the restricted wireless network node in order to cause the restricted wireless network node to adjust the signal transmitted in the direction of the user device to avoid or reduce interference at the user device; and

means for establishing a connection, by the user device, with a serving node subsequent to the adjustment of the signal transmitted in the direction of the user device.

13. A method for wireless communication, comprising:

receiving, at a restricted wireless network node, information from a user device that is not subscribed to the restricted wireless network node, wherein the information is determined from a signal provided from the restricted wireless network node; and

adjusting, by the restricted wireless network node, a signal transmitted in the direction of the user device by the restricted wireless network node based on the information received from the user device, in order to reduce or avoid interference at the user device, and in order for the user device to establish a connection with a serving node subsequent to the adjustment of the signal transmitted in the direction of the user device.

14. The method of claim 13 wherein the information includes spatial channel information.

15. The method of claim 14 wherein the information further includes signal strength information.

16. The method of claim 15 wherein the user device is served by a first wireless network node that comprises a macrocell node.

17. The method of claim 16 wherein the restricted wireless network node comprises a femtocell node.

18. The method of claim 13 wherein the adjusting includes beamforming at the output of the restricted wireless network node so as to mitigate interference in the direction of the user device.

19. A non-transitory computer program product comprising a non-transitory computer-readable medium, the computer-readable medium including codes for causing a computer to:

receive, at a restricted wireless network node, information from a user device that is not subscribed to the restricted wireless network node, wherein the information is determined from a signal provided from the restricted wireless network node; and

adjust, at the restricted wireless network node, a signal transmitted in a direction of the user device by the restricted wireless network node based on the information, in order to reduce or avoid interference at the user device, and in order for the user device to establish a connection with a serving node subsequent to the adjustment of the signal transmitted in the direction of the user device.

20. The non-transitory computer program product of claim 19 wherein the codes include codes for beamforming at the output of the restricted wireless network node so as to mitigate interference in the direction of the user device.

21. A wireless communications network node, comprising:

a receiver module of the wireless communications network node configured to receive a signal from a user device not subscribed to the wireless communications network node, said signal including node information regarding an output signal provided from the wireless communications network node;

a processor module of the wireless communications network node configured to determine, based on the information, output signal adjustment information to reduce or avoid interference at the user device;

a transmitter module of the wireless communications network node configured to adjust the output based on the output signal adjustment information and establish a connection with the user device subsequent to the adjustment of the output based on the output signal adjustment information.

22. The node of claim 21 wherein the node information includes spatial channel information.

23. The node of claim 22 wherein the node information further includes signal strength information.

24. The node of claim 21 wherein the adjusting includes beamforming at the node output so as to mitigate interference in the direction of the user device.

25. A wireless communications network node, comprising:

means for receiving, at the wireless communications network node, a signal from a user device not subscribed to the wireless communications network node, said signal including node information regarding an output signal provided from the network node;

means for determining, at the wireless communications network node, based on the node information, output signal adjustment information to reduce or avoid interference at the user device;

means for adjusting, at the wireless communications network node, the output signal based on the output signal adjustment information; and

means for establishing a connection with the user device subsequent to the adjustment of the output signal based on the output signal adjustment information.

26. The node of claim 25 further including means for beamforming at the node output so as to mitigate interference in the direction of the user device.

27. A method for wireless communication, comprising:

receiving, at a restricted node, from a user device not subscribed to the restricted node, a request to communicate;

establishing, by the restricted node, a communication link with the user device not subscribed to the restricted node;

receiving, by the restricted node, from the communication link with the user device not subscribed to the restricted node, information regarding an output signal of the restricted node; and

adjusting, by the restricted node, based on the information from the user device not subscribed to the restricted node, a signal transmitted in the direction of the user device by the restricted node, in order to reduce or avoid interference at the user device not subscribed to the restricted node, and in order for the user device to establish a connection with a serving node subsequent to the adjustment of the signal transmitted in the direction of the user device.

28. The method of claim 27 wherein the information includes spatial channel information.

29. The method of claim 28 wherein the information further includes signal strength information.

30. The method of claim 27 wherein the adjusting includes beamforming so as to mitigate interference in the direction of the user device.

31. The method of claim 27 further including receiving information regarding a reference signal received power (RSRP) of a first wireless network node in communication with the user device and wherein the adjusting is performed only when the RSRP is below a predefined threshold.

32. The method of claim 27 further including receiving information regarding a reference signal received quality (RSRQ) of a first wireless network node in communication with the user device and wherein the adjusting is performed only when the RSRQ is below a minimum threshold.

33. A non-transitory computer program product comprising a non-transitory computer-readable medium, the computer-readable medium including codes for causing a computer to:

receive, at a restricted node, from a user device not subscribed to the restricted node, a request to communicate;

establish, by the restricted node, a communication link with the user device not subscribed to the restricted node;

receive, by the restricted node, from the communication link with the user device not subscribed to the restricted node, information from the user device not subscribed to the network node regarding the restricted node; and

adjust, by the restricted node, based on the information, a signal transmitted in a direction of the user device by the restricted node, in order to reduce or avoid interference at the user device not subscribed to the restricted node, and in order for the user device to establish a connection with a serving node subsequent to the adjustment of the signal transmitted in the direction of the user device.

34. The non-transitory computer program product of claim 33 wherein the codes further include codes to beamform at the output so as to mitigate interference in the direction of the user device.

35. A wireless network node, comprising:

a receiver module of the wireless network node configured to;

receive, from a user device not subscribed to the network node, a request to communicate;

establish a communication link with the user device not subscribed to the network node; and

receive, from the communication link with the user device not subscribed to the network node, information from the user device not subscribed to the network node regarding the wireless network node;

a processor module of the wireless network node configured to determine, based on the information received from the user device not subscribed to the network node, output signal adjustment information; and

a transmitter module of the wireless network node configured to adjust a signal transmitted in a direction of the user device based on the output signal adjustment information, in order to reduce or avoid interference at the user device not subscribed to the restricted node, and in order for the user device to establish a connection with a serving node subsequent to the adjustment of the signal transmitted in the direction of the user device.

36. The node of claim 35 wherein the information includes spatial channel information.

37. The node of claim 36 wherein the information further includes signal strength information.

38. The node of claim 35 wherein the output is beamformed so as to mitigate interference in the direction of the user device.

39. A wireless network node, comprising:

means for receiving by the wireless network node, from a user device not subscribed to the wireless network node, a request to communicate;

means for establishing, by the wireless network node, a communication link with the user device not subscribed to the wireless network node;

means for receiving by the wireless network node, from the communication link with the user device not subscribed to the wireless network node, information regarding the wireless network node;

means for determining by the wireless network node, based on the information received from the user device not subscribed to the wireless network node, output signal adjustment information; and

means for adjusting a signal transmitted in a direction of the user device by the wireless network node based on the output signal adjustment information, in order to reduce or avoid interference at the user device not subscribed to the restricted node, and in order for the user device to establish a connection with a serving node subsequent to the adjustment of the signal transmitted in the direction of the user device.