Cross-cell MIMO

• US 8,855,040 B1
• Filed: 10/02/2008
• Issued: 10/07/2014
• 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, Carroll Philip, Gunter, Michial Allen
• Primary Examiner(s): Taha, Shaq
• Application Number:
  US12/244,376
• Time in Patent Office: 2,196 Days
• Field of Search: 370/315
• US Class Current: 370/315
• 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 of performing cross-cell MIMO, comprising:

establishing, at a first base station, a first wireless data connection with a receiving device;

identifying a second base station remote from the first base station that is transmitting data to the receiving device over a second wireless data connection;

receiving, at the first base station and as having been sent from the second base station, first communications information that characterizes a transmission from the second base station to the receiving device, wherein the first communications information includes first data that is to be processed by the receiving device and a transfer function used, by the second base station, to transmit the first data to the receiving device;

generating second communications information for transmission, from the first base station to the receiving device, of second data that is to be processed by the receiving device, the second communications information being generated using the first data, the second data, and the transfer function, wherein the second communications information is generated, in part, to reduce interference imposed on the second communications information by the first communications information, wherein generating the second communications information comprises subtracting, from the second data, a result of an operation based on the first data and the transfer function; and

transmitting, from the first base station, the second communications information to the receiving device.

2. The method of claim 1, further comprising:

establishing a communication link between the first base station and the second base station in response to the identification of the second base station;

wherein the first communications information is received at the first base station over the communications link.

3. The method of claim 2, wherein identifying the second base station comprises detecting a pilot signal associated with the second base station.

4. The method of claim 1, wherein the result of the operation based on the first data and the transfer function comprises a product of the first data and the transfer function.

5. The method of claim 1, wherein receiving the first communications information comprises receiving the first communications information over a back-link.

6. The method of claim 5, wherein receiving the first communications information over a back-link comprises receiving the first communications information over a fiber-optic link.

7. The method of claim 1, further comprising determining a location of a wireless device, wherein generating second communications information comprises generating the second communications information based on the location of the wireless device.

8. The method of claim 7, wherein the location is proximate to a communications border.

9. The method of claim 1, further comprising defining a MIMO array, wherein the MIMO array comprises the first base station and the second base station.

17. The method of claim 1, further comprising:

determining that the second base station is an interference source for the receiving device; and

in response to determining that the second base station is an interference source for the receiving device, transmitting the second communications information to the receiving device.

18. The method of claim 17, wherein:

receiving the first communications information comprises receiving the first communications information over a back-link that communicably couples the first base station to the second base station; and

transmitting the second communications information to the receiving device comprises transmitting the second communications information over a wireless communications channel that is different than the back-link.

19. The method of claim 1, further comprising:

determining that the receiving device is proximate to a communications border between a communications range of the first base station and a communications range of the second base station; and

in response to determining that the receiving device is proximate to the communications border, transmitting the second communications information to the receiving device.

20. The method of claim 1, further comprising:

determining that a power constraint is less than a threshold value, the power constraint being based on signal power of the first base station and interference power of the first base station; and

in response to determining that the power constraint is less than the threshold value, increasing the signal power of the first base station.

10. A cross-cell MIMO system, comprising:

a first base station that;

establishes a first wireless data connection with a receiving device;

identifies a second base station remote from the first base station that transmits data to the receiving device over a second wireless data connection;

receives, from the second base station, first communications information that characterizes a transmission from the second base station to the receiving device, wherein the first communications information includes first data that is to be processed by the receiving device and a transfer function that is used, by the second base station, to transmit the first data to the receiving device; and

transmits second communications information to the receiving device;

an interference cancellation engine configured to generate the second communications information for transmission, from the first base station to the receiving device, of second data that is to be processed by the receiving device, the second communications information being generated using the first data, the second data, and the transfer function, wherein the second communications information is generated, in part, to reduce interference imposed on the second communications information by the first communications information, wherein the interference cancellation engine is further configured to generate the second communications information by subtracting, from the second data, a result of an operation based on the first data and the transfer function.

11. The system of claim 10, wherein the first base station is configured to identify a location of one or more wireless devices, and the interference cancellation engine is further configured to generate the second communications information based on the identified location.

12. The system of claim 10, wherein the first base station and the second base station comprise a MIMO array.

13. The system of claim 10, wherein the first base station is configured to identify a location of one or more wireless devices, and the interference cancellation engine is configured to selectively reduce interference based on the location of the one or more wireless devices.

14. The system of claim 13, wherein the interference cancellation engine is configured to reduce interference from the second base station in response to the one or more wireless devices being located in a defined region.

15. The system of claim 14, wherein the defined region comprises an area proximate to a communications border.

16. A cross-cell MIMO device, comprising:

a transceiver to establish, at a first base station, a first wireless data connection with a receiving device;

one or more tangible recordable storage media storing instructions that, when executed by one or more processors, perform operations comprising;

identifying a second base station remote from the first base station that is transmitting data to the receiving device over a second wireless data connection;

receiving, at the first base station and as having been sent from the second base station, first communications information that characterizes a transmission from the second base station to the receiving device, wherein the first communications information includes first data that is to be processed by the receiving device and a transfer function that is used, by the second base station, to transmit the first data to the receiving device;

generating second communications information for transmission, from the first base station to the receiving device, of second data that is to be processed by the receiving device, the second communications information being generated using the first data, the second data, and the transfer function, wherein the second communications information is generated, in part, to reduce interference imposed on the second communications information by the first communications information, wherein generating the second communications information comprises subtracting, from the second data, a result of an operation based on the first data and the transfer function; and

a transceiver for transmitting, from the first base station, the second communications information to the receiving device.