DETECTING AND AVOIDING INTERMODULATION INTERFERENCE

• US 20150222371A1
• Filed: 02/04/2014
• Published: 08/06/2015
• Est. Priority Date: 02/04/2014
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Afkhami, Hassan Kaywan, Rajkotia, Purva Rameshchandra
• Granted Patent: US 9,473,256 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04B 17/16 Test equipment located at the transmitter
• CPC Class Codes: H04B 17/17 Detection of non-compliance or faulty performance, e.g. response deviations H04B17/18 takes precedence
• CPC Class Codes: H04B 17/19 Self-testing arrangements
• CPC Class Codes: H04B 2203/5425 improving S/N by matching impedance, noise reduction, gain control
• CPC Class Codes: H04B 2203/5495 having measurements and testing channel
• CPC Class Codes: H04B 3/54 Systems for transmission via power distribution lines

Abstract

A first device and a second device may coordinate to determine a power level or frequency in a first frequency band that is associated with causing intermodulation (IM) interference at a second frequency band (e.g., a protected frequency band). An IM interference detection test may include at least a first test signal transmitted from the first device to the second device via a communications medium. The second device may detect for the presence of IM interference associated with the first test signal. A series of test signals may be used to identify power levels and/or frequencies that cause IM interference in the second frequency band. A transmitting device may improve performance by increasing power for particular frequencies up to a power level that maintains IM interference below a threshold level.

Claims

1. A method for detecting intermodulation (IM) interference, the method comprising:

transmitting, from a first device coupled to a communications medium to a second device coupled to the communications medium, a first test signal at a first power level; and

determining IM interference associated with the first power level between the first device and the second device.

2. The method of claim 1, further comprising determining a maximum power level for a first plurality of frequencies that does not produce IM interference beyond a threshold interference level for a second plurality of frequencies.

3. The method of claim 1, further comprising:

communicating a test setup message from the first device to the second device.

4. The method of claim 3, wherein the test setup message identifies the first power level of the first test signal.

5. The method of claim 3, wherein the test setup message indicates a test sequence for a plurality of test signals including the first test signal.

6. The method of claim 5, wherein the test sequence is associated with sequentially testing each of the plurality of test signals at a different power level.

7. The method of claim 5, wherein the test sequence is associated with at least one of:

a stepwise sequence for a plurality of frequencies, or

a pattern sequence for a plurality of frequencies.

8. The method of claim 1, further comprising:

receiving feedback from the second device indicating whether the second device has detected IM interference above a threshold interference level as a result of the first test signal.

9. The method of claim 8, further comprising:

determining a second power level for a second test signal based at least in part on whether the second device has detected IM interference above the threshold interference level as a result of the first test signal.

10. The method of claim 9, further comprising:

transmitting the second test signal at the second power level after transmitting the first test signal at the first power level.

11. The method of claim 1, wherein the first test signal includes a first set of frequencies, the method further comprising:

transmitting a second test signal that includes a second set of frequencies, at least one frequency of the second set of frequencies being different from the first set of frequencies.

12. The method of claim 11, wherein the first set of frequencies and the second set of frequencies are determined prior to a start of an IM interference detection test.

13. The method of claim 11, further comprising:

receiving feedback from the second device indicating whether the second device has detected IM interference above a threshold interference level as a result of the first test signal; and

determining the second set of frequencies for the second test signal based, at least in part, on the feedback.

14. The method of claim 1, further comprising:

receiving a results message from the second device indicating that IM interference was detected above a threshold interference level in association with an identified power level, an identified frequency, or an identified combination power level and frequency.

15. The method of claim 14, wherein the results message is received as a broadcast message via the communications medium.

16. The method of claim 1, wherein the first test signal is part of an IM interference detection test that is coordinated between the first device and the second device.

17. A first device, comprising:

a transmitter capable of coupling with a communications medium, the transmitter configured to transmit a first test signal at a first power level; and

an intermodulation (IM) interference test module configured to coordinate with a second device coupled to the communications medium to determine IM interference associated with the first power level between the first device and the second device.

18. The first device of claim 17, wherein the IM interference test module is further configured to determine a maximum power level for a first plurality of frequencies that does not produce IM interference beyond a threshold interference level for a second plurality of frequencies.

19. The first device of claim 17, wherein the IM interference test module is further configured to communicate a test setup message from the first device to the second device.

20. The first device of claim 19, wherein the test setup message indicates a test sequence for a plurality of test signals including the first test signal, wherein the test sequence includes one of:

a sequence of different power levels for ones of the plurality of test signals,

a stepwise sequence for a plurality of frequencies, or

a pattern sequence for a plurality of frequencies.

21. The first device of claim 17, wherein the IM interference test module is further configured to:

receive feedback from the second device indicating whether the second device has detected IM interference above a threshold interference level as a result of the first test signal.

22. The first device of claim 21, wherein the IM interference test module is further configured to:

determine a second power level for a second test signal based at least in part on whether the second device has detected IM interference above the threshold interference level as a result of the first test signal.

23. The first device of claim 22, wherein the IM interference test module is further configured to, after transmitting the first test signal at the first power level, transmit the second test signal at the second power level.

24. The first device of claim 17, wherein the first test signal includes a first set of frequencies and wherein the transmitter is further configured to:

transmit a second test signal that includes a second set of frequencies, at least one frequency of the second set of frequencies being different from the first set of frequencies.

25. The first device of claim 17, further comprising:

a receiver configured to receive a results message from the second device indicating that IM interference was detected above a threshold interference level in association with an identified power level, an identified frequency, or an identified combination of power level and frequency,

wherein the transmitter is configured to limit transmissions for the identified power level, identified frequency, or identified combination of power level and frequency.

26. A device, comprising:

a receiver capable of coupling with a communications medium and configured to receive at least a first test signal at a first power level from a first device; and

an intermodulation (IM) interference detection module configured to determine IM interference associated with the first power level.

27. The device of claim 26, further comprising:

the receiver configured to receive a test setup message from the first device; and

the IM interference detection module configured to detect IM interference based at least in part on the test setup message.

28. The device of claim 26, further comprising:

a transmitter configured to transmit feedback from to the first device, the feedback indicating whether IM interference was detected above a threshold interference level as a result of the first test signal.

29. The device of claim 26, further comprising:

the IM interference detection module configured to determine an identified power level, an identified frequency, or an identified combination power level and frequency which is associated with causing IM interference above a threshold interference level when transmitted via the communications medium; and

a transmitter configured to transmit a results message to the first device indicating the identified power level, the identified frequency, or the identified combination power level and frequency.

30. One or more machine-readable media having stored therein a program product, which when executed by one or more processor units causes the one or more processor units to perform operations that comprise:

transmit, from a first device coupled to a communications medium to a second device coupled to the communications medium, a first test signal at a first power level; and

determine intermodulation (IM) interference associated with the first power level between the first device and the second device.