ESTIMATING INTERFERENCE IN MULTI CHANNEL SYSTEMS

• US 20110182344A1
• Filed: 08/04/2009
• Published: 07/28/2011
• Est. Priority Date: 10/06/2008
• Status: Active Grant

• Current Assignee: Ceragon Networks Incorporated
• Original Assignee: Ceragon Networks Incorporated
• Inventors: Mizrahi, Haggai, Rosenhouse, Isaac
• Granted Patent: US 8,737,497 B2
• Time in Patent Office: Days
• US Class Current: 375/224
• CPC Class Codes: H04B 17/345 Interference values signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR] H04B17/336
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity
• CPC Class Codes: H04L 2025/03426 transmission using multiple-input and multiple-output channels
• CPC Class Codes: H04L 25/03006 Arrangements for removing intersymbol interference

Abstract

A method for estimating interference between a plurality of carrier signals in a multi-channel system including injecting pilot symbols into a first carrier signal and transmitting the first carrier signal, transmitting a second carrier signal, receiving at least the first carrier signal and the second carrier signal, and estimating interference between the received first carrier signal and the received second carrier signal based, at least in part, on measuring the received first carrier signal when a pilot symbol of the first carrier signal is received. A multi-channel communication system including a plurality of transmitters for a plurality of carrier signals, a pilot symbol injector for injecting silent pilot symbols into at least one of the carrier signals, a plurality of receivers for the plurality of carrier signals, and an interference estimator configured to estimate interference between at least two of the plurality of carrier signals based, at least in part, on receiving silent pilot symbols in at least one of the at least two of the plurality of carrier signals. Related apparatus and methods are also described.

Claims

1. A method for estimating interference between a plurality of carrier signals in a multi-channel system comprising:

injecting pilot symbols into a first carrier signal and transmitting the first carrier signal;

transmitting a second carrier signal;

receiving at least the first carrier signal and the second carrier signal; and

estimating interference between the received first carrier signal and the received second carrier signal based, at least in part, on measuring the received first carrier signal when a pilot symbol of the first carrier signal is received.

2. The method of claim 1 in which the first carrier signal and the second carrier signal are orthogonally polarized relative to each other.

3. The method of claim 1 in which the estimating comprises estimating differential phase.

4. The method of claim 3 in which the estimating is performed by:

equalizing the received first carrier signal and the received second carrier signal; and

measuring the differential phase between the equalized received first carrier signal and the equalized received second carrier signal,

when a pilot symbol of the first carrier signal is received.

5. The method of claim 1 in which at least some of the pilot symbols injected into the first carrier comprise silent pilot symbols.

6. The method of claim 5 in which the injecting silent pilot symbols into the first carrier signal is done substantially at the same time regular pilot symbols are injected into the second carrier signal.

7. The method of claim 1 in which the injecting pilot symbols into a first carrier signal comprises injecting a plurality of consecutive pilot symbols into the first carrier signal.

8. The method of claim 1 in which the plurality of carrier signals comprises more than two carrier signals.

9. The method of claim 8 in which the plurality of carrier signals are injected with pilot symbols and the plurality of carrier signals are transmitted.

10. The method of claim 9 in which the injecting pilot symbols into a first one of the plurality of carrier signals is done substantially at the same time regular pilot symbols are injected into others of the plurality of carrier signals.

11. The method of claim 9 in which the injecting regular pilot symbols into a first one of the plurality of carrier signals is done substantially at the same time as silent pilot symbols are injected into others of the plurality of carrier signals.

15. Apparatus using the method of claim 1.

16. A computer program embodied on a computer-readable medium for implementing the method of claim 1.

12. A method for estimating interference between a plurality of carrier signals in a multi-channel system comprising:

transmitting signals in a first carrier and in a second carrier;

receiving at least a signal of the first carrier and a signal of the second carrier;

estimating the differential phase between the first carrier and the second carrier based, at least in part, on measuring the differential phase between the received signal of the first carrier and the received signal of the second carrier when a known symbol of the first carrier is received.

13. A point-to-point communication system comprising:

a plurality of receivers for a plurality of carrier signals; and

an interference estimator configured to estimate differential phase between at least two of the plurality of carrier signals based, at least in part, on receiving silent pilot symbols in at least one of the at least two of the plurality of carrier signals.

14. A multi-channel communication system comprising:

a plurality of transmitters for a plurality of carrier signals;

a pilot symbol injector for injecting silent pilot symbols into at least one of the carrier signals,

a plurality of receivers for the plurality of carrier signals; and

an interference estimator configured to estimate interference between at least two of the plurality of carrier signals based, at least in part, on receiving silent pilot symbols in at least one of the at least two of the plurality of carrier signals.

17. Apparatus for estimating interference between a plurality of carrier signals in a multi-carrier communication system comprising:

means for injecting silent pilot symbols into a first carrier signal;

means for transmitting the first carrier signal;

means for transmitting a second carrier signal;

means for receiving at least the first carrier signal and the second carrier signal;

means for estimating interference between the first carrier signal and the second carrier signal based, at least in part, on measuring the received signal of the first carrier signal during reception of the silent pilot symbols of the first carrier.