Cross-cell MIMO

• US 9,548,821 B1
• Filed: 10/06/2014
• Issued: 01/17/2017
• Est. Priority Date: 04/21/2008
• Status: Expired due to Fees

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google Inc. (Alphabet Inc.)
• Inventors: Gossett, C. Philip, Gunter, Michial Allen
• Primary Examiner(s): Washburn, Daniel
• Assistant Examiner(s): Hughes, Eboni
• Application Number:
  US14/506,800
• Time in Patent Office: 834 Days
• Field of Search: 375/267, 370/208, 370/329, 370/331, 370/347, 455/63.1
• US Class Current: 1/1
• CPC Class Codes: H04B 1/00 Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
• CPC Class Codes: H04B 15/00 Suppression or limitation of noise or interference by means associated with receiver H04B1/10
• CPC Class Codes: H04B 17/00 Monitoring; Testing of line transmission systems H04B3/46; arrangements for monitoring or testing transmission systems employing electromagnetic waves other than radio waves H04B10/07
• CPC Class Codes: H04B 7/024 Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems
• CPC Class Codes: H04B 7/0413 MIMO systems
• CPC Class Codes: H04J 11/005 of intercell interference
• CPC Class Codes: H04W 72/00 Local resource management
• CPC Class Codes: H04W 72/54 based on quality criteria

Abstract

Methods, systems, and apparatus, including computer program products, for implementing interference cancellation across base stations. Communications information for transmitting to a receiving device is received from a first base station at a second base station. At the second base station, second communications information is generated for transmission to the receiving device from the second base station. The second communications information comprises data to reduce interference with the first communications information.

Claims

1. A method, comprising:

identifying that wireless communications between a wireless device and a first base station are interfering with wireless communications between the wireless device and a second base station, wherein the wireless device, the first base station, and the second base station are geographically remote from each other;

in response to identifying that the wireless communications between the wireless device and the first base station are interfering with the wireless communications between the wireless device and the second base station;

(i) providing, from the first base station and to the second base station, in a transmission that is separate from the wireless communications between the wireless device and the first base station, data that characterizes the wireless communications between the wireless device and the first base station, and

(ii) causing the second base station to modify, using the data that characterizes the wireless communications between the wireless device and the first base station, the wireless communications between the wireless device and the second base station so as to at least partially prevent the wireless communications between the wireless device and the first base station from interfering with the wireless communications between the wireless device and the second base station;

identifying that wireless communications between the wireless device and a third base station are interfering with wireless communications between the wireless device and the second base station; and

in response to identifying that the wireless communications between the wireless device and the third base station are interfering with the wireless communications between the wireless device and the second base station;

(i) providing, from the third base station and to the second base station, in a transmission that is separate from the wireless communications between the wireless device and the third base station, data that characterizes the wireless communications between the wireless device and the third base station, and

(ii) causing the second base station to modify, using the data that characterizes the wireless communications between the wireless device and the third base station, the wireless communications between the wireless device and the second base station, so as to at least partially prevent the wireless communications between the wireless device and the third base station from interfering with the wireless communications between the wireless device and the second base station.

2. The method of claim 1, wherein identifying that the wireless communications between the wireless device and the first base station are interfering with the wireless communications between the wireless device and the second base station comprises:

detecting, at the second base station, a pilot signal emitted from the wireless device; and

determining, based on the pilot signal, whether the wireless device is presently part of a communications network associated with the second base station.

3. The method of claim 2, wherein identifying that the wireless communications between the wireless device and the first base station are interfering with the wireless communications between the wireless device and the second base station comprises determining that the wireless device is not presently part of the communications network associated with the second base station.

4. The method of claim 1, wherein providing, from the first base station and to the second base station, in the transmission that is separate from the wireless communications between the wireless device and the first base station, the data that characterizes the wireless communications between the wireless device and the first base station comprises sending the data that characterizes the wireless communications between the wireless device and the first base station over a physical backlink that connects the first base station and the second base station.

5. The method of claim 1, wherein the data provided, from the first base station to the second base station, that characterizes the wireless communications between the wireless device and the first base station comprises data that indicates a transfer function that specifies a manner in which the first base station is to transmit messages in the wireless communications between the wireless device and the first base station.

6. The method of claim 5, wherein the first base station determines the transfer function based on characteristics of a pilot signal emitted from the wireless device.

7. The method of claim 5, wherein the second base station modifies the wireless communications between the wireless device and the second base station based on the transfer function.

8. The method of claim 7, wherein the second base station modifies the wireless communications between the wireless device and the second base station by performing one or more operations that are indicated by the transfer function on messages that are to be transmitted from the second base station to the wireless device.

9. The method of claim 1, wherein:

the data provided from the first base station to the second base station that characterizes the wireless communications between the wireless device and the first base station includes (i) first messages that are to be transmitted from the first base station to the wireless device as part of the wireless communications between the wireless device and the first base station and (ii) a transfer function for processing the first messages; and

the second base station modifies the wireless communications between the wireless device and the second base station by subtracting, from second messages that are to be transmitted from the second base station to the wireless device, a representation of the first messages as processed using the transfer function.

10. The method of claim 1, wherein the first base station and the second base station are arranged in a collection of base stations that define a Multiple-Input, Multiple Output (MIMO) array.

11. The method of claim 1, further comprising determining whether the wireless device is located proximate to the borders of both a first communications region associated with the first base station and a second communications region associated with the second base station.

18. The method of claim 4, wherein the physical backlink comprises a fiber optic backlink.

19. The method of claim 1, wherein the data provided from the first base station to the second base station that characterizes the wireless communications between the wireless device and the first base station comprises a message that is assigned to be wirelessly transmitted from the first base station to the wireless device.

20. The method of claim 19, further comprising transmitting the message, from the first base station and to the wireless device, in a second transmission that is part of the wireless communications between the wireless device and the first base station.

12. A communications system, comprising:

a first base station in wireless communication with a mobile device, the first base station including a first plurality of wireless access points;

a second base station in wireless communication with the mobile device, the second base station including a second plurality of wireless access points;

a third base station in wireless communication with the mobile device, the third base station including a third plurality of wireless access points;

a first back-link that forms a wired communications connection among two or more base stations including the first base station and the second base station; and

a second back-link that forms a wired communications connection among two or more base stations including the second base station and the third base station;

wherein the first base station is configured to send, over the first back-link to the second base station and in response to receiving an indication that wireless communications between the first base station and the mobile device are interfering with wireless communications between the second base station and the mobile device, first data that is to be transmitted wirelessly by the first base station to the mobile device,

wherein the second base station is configured to modify the wireless communications between the second base station and the mobile device based on the first data sent over the first back-link from the first base station so as to at least partially cancel interference experienced by the second base station or the mobile device that is a result of the wireless communications between the first base station and the mobile device,

wherein the third base station is configured to send, over the second back-link to the second base station and in response to receiving an indication that wireless communications between the third base station and the mobile device are interfering with wireless communications between the second base station and the mobile device, second data that is to be transmitted wirelessly by the third base station to the mobile device,

wherein the second base station is configured to modify the wireless communications between the second base station and the mobile device based on the second data sent over the second back-link from the third base station so as to at least partially cancel interference experienced by the second base station or the mobile device that is a result of the wireless communications between the third base station and the mobile device.

13. The communications system of claim 12, wherein the first back-link comprises a physical connection between the first base station and the second base station.

14. The communications system of claim 12, wherein the first base station and the second base station are arranged in a collection of base stations that define a Multiple-Input, Multiple Output (MIMO) array.

15. The communications system of claim 12, wherein the second base station is configured to identify that the wireless communications between the first base station and the mobile device are interfering with the wireless communications between the second base station and the mobile device based on a first determination that the mobile device is located within communications range of the second base station and a second determination that the mobile device is not presently part of a communications network associated with the second base station.

16. The communications system of claim 12, wherein the first base station is further configured to send, to the second base station and in response to receiving the indication that wireless communications between the third base station and the mobile device are interfering with wireless communications between the second base station and the mobile device, a transfer function that indicates a manner in which the first base station transmits data to the wireless device.

17. A system for reducing wireless interference among base stations, comprising:

one or more computers; and

one or more computer-readable storage media having instructions stored thereon that, when executed by the one or more computers, cause performance of operations comprising;

identifying that wireless communications between a wireless device and a first base station are interfering with wireless communications between the wireless device and a second base station, wherein the wireless device, the first base station, and the second base station are geographically remote from each other;

in response to identifying that the wireless communications between the wireless device and the first base station are interfering with the wireless communications between the wireless device and the second base station;

(i) providing, from the first base station and to the second base station, in a transmission that is separate from the wireless communications between the wireless device and the first base station, data that characterizes the wireless communications between the wireless device and the first base station, and

(ii) causing the second base station to modify, using the data that characterizes the wireless communications between the wireless device and the first base station, the wireless communications between the wireless device and the second base station so as to at least partially prevent the wireless communications between the wireless device and the first base station from interfering with the wireless communications between the wireless device and the second base station;

identifying that wireless communications between the wireless device and a third base station are interfering with wireless communications between the wireless device and the second base station; and

in response to identifying that the wireless communications between the wireless device and the third base station are interfering with the wireless communications between the wireless device and the second base station;

(i) providing, from the third base station and to the second base station, in a transmission that is separate from the wireless communications between the wireless device and the third base station, data that characterizes the wireless communications between the wireless device and the third base station, and

(ii) causing the second base station to modify, using the data that characterizes the wireless communications between the wireless device and the third base station, the wireless communications between the wireless device and the second base station, so as to at least partially prevent the wireless communications between the wireless device and the third base station from interfering with the wireless communications between the wireless device and the second base station.