Cancelling intermodulation interference

• US 9,960,797 B2
• Filed: 07/10/2014
• Issued: 05/01/2018
• Est. Priority Date: 07/10/2014
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Heinikoski, Kauko, Leinonen, Marko E
• Primary Examiner(s): Musa, Abdelnabi O
• Application Number:
  US14/422,800
• Publication Number:
  US 20160261297A1
• Time in Patent Office: 1,391 Days
• CPC Class Codes: H04B 1/1027 assessing signal quality or detecting noise/interference for the received signal
• CPC Class Codes: H04B 1/109 by improving strong signal performance of the receiver when strong unwanted signals are present at the receiver input
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver
• CPC Class Codes: H04L 27/0008 arrangements for allowing a transmitter or receiver to use more than one type of modulation negotiating modulation type for two-way transmission paths H04L5/1453
• CPC Class Codes: H04L 5/1461 Suppression of signals in the return path, i.e. bidirectional control circuits

Abstract

Cancelling of intermodulation interference is described. A digital signal sample (x) is received and a power of the received digital signal sample is obtained (243). Based on the obtained power, at least one model value is obtained from a model (244) that models model values of a non-linearity in amplitude and phase of a received signal that passes through passive and active components in the receiver. The model values correspond to a plurality of powers of the received signal. Intermodulation interference is then cancelled by multiplying (245) the received digital signal sample with the obtained at least one model value, thereby obtaining an output digital signal sample (y) from which intermodulation interference, inflicted by the receiver, is cancelled.

Claims

1. A method, performed by a receiver, for cancelling intermodulation interference, the method comprising:

receiving a digital signal sample;

obtaining a power of the received digital signal sample;

obtaining, based on the obtained power, at least one model value from a plurality of model values generated according to a model, wherein the model represents a non-linearity in amplitude and phase of a received signal that passes through passive and active components in the receiver, and wherein the plurality of model values correspond to a plurality of powers of the received signal;

cancelling intermodulation interference by multiplying the received digital signal sample with the obtained at least one model value, thereby obtaining an output digital signal sample from which intermodulation interference, inflicted by the receiver, is cancelled.

2. The method of claim 1:

wherein the plurality of model values also correspond to a plurality of temperature values that represent temperatures of the passive and active components in the receiver;

the method further comprising determining a temperature value that represents a temperature of the passive and active components in the receiver; and

wherein obtaining the at least one model value is based also on the determined temperature.

3. The method of claim 1, wherein the model is a predetermined fixed algorithm.

4. The method of claim 1, wherein the model is an adaptive algorithm;

wherein the method further comprises at least one of;

updating the model based on a quality of the received signal; and

updating the model by minimizing a difference between the received signal and an expected received signal.

5. The method of claim 4, wherein the updating the model is performed in response to any of:

determining that the quality of the received signal is below a threshold quality; and

determining that the difference between the received signal and an expected received signal is greater than a difference threshold.

6. The method of claim 4, wherein the quality of the received signal is any of:

a signal to interference ratio;

a signal to noise ratio;

a bit error rate; and

an error vector magnitude.

7. The method of claim 1:

wherein the model is in the form of a lookup table (LUT); and

wherein the plurality of model values are in the form of LUT values that are indexed in the LUT by the obtained power.

8. The method of claim 7:

wherein the plurality of model values also correspond to a plurality of temperature values that represent temperatures of the passive and active components in the receiver;

the method further comprising determining a temperature value that represents a temperature of the passive and active components in the receiver; and

wherein the obtaining of a model value from a model is based also on the determined temperature;

wherein the plurality of model values of the model are indexed in the LUT by obtained power and indexed in the LUT by temperature.

9. The method of claim 1, further comprising:

determining a power of a blocking signal in the receiver; and

in response to the power of the blocking signal being higher than a first threshold and/or the power of the received digital signal sample being lower than a second threshold, multiplying the received digital signal sample with the obtained at least one model value.

10. The method of claim 1, wherein the obtaining of a power of the received digital signal sample comprises any of:

integrated sliding window power detection; and

power calculation by use of an integrator implemented by way of an infinite impulse response (IIR) filter.

11. The method of claim 1, wherein the obtaining of a power of the received digital signal sample comprises obtaining the power from an automatic gain control (AGC) algorithm that operates to control a variable gain amplifier (VGA) in the receiver.

12. The method of claim 1, wherein the obtaining of a power of the received digital signal sample comprises obtaining the power from an input of a low noise amplifier (LNA) in the receiver.

13. The method of claim 1, wherein the plurality of model values are complex values.

14. The method of claim 13, wherein the plurality of model values are Volterra polynomial coefficients.

15. A receiver, comprising:

radio frequency circuitry;

a processor;

memory operatively coupled to the processor and containing instructions executable by the processor to cause the receiver to;

receive a digital signal sample;

obtain a power of the received digital signal sample;

obtain, based on the obtained power, at least one model value from a plurality of model values generated according to a model, wherein the model represents a non-linearity in amplitude and phase of a received signal that passes through passive and active components in the receiver, and wherein the plurality of model values correspond to a plurality of powers of the received signal;

cancel intermodulation interference by multiplying the received digital signal sample with the obtained at least one model value to thereby obtain an output digital signal sample from which intermodulation interference, inflicted by the receiver, is cancelled.

16. A transceiver, comprising:

a transmitter;

a receiver comprising;

radio frequency circuitry;

a processor;

memory operatively coupled to the processor and containing instructions executable by the processor to cause the receiver to;

receive a digital signal sample;

obtain a power of the received digital signal sample;

obtain, based on the obtained power, at least one model value from a plurality of model values generated according to a model, wherein the model represents a non-linearity in amplitude and phase of a received signal that passes through passive and active components in the receiver, and wherein the plurality of model values correspond to a plurality of powers of the received signal;

cancel intermodulation interference by multiplying the received digital signal sample with the obtained at least one model value to thereby obtain an output digital signal sample from which intermodulation interference, inflicted by the receiver, is cancelled.

17. A wireless communication node, comprising:

a receiver comprising;

radio frequency circuitry;

a processor;

memory operatively coupled to the processor and containing instructions executable by the processor to cause the receiver to;

receive a digital signal sample;

obtain a power of the received digital signal sample;

obtain, based on the obtained power, at least one model value from a plurality of model values generated according to a model, wherein the model represents a non-linearity in amplitude and phase of a received signal that passes through passive and active components in the receiver, and wherein the plurality of model values correspond to a plurality of powers of the received signal;

cancel intermodulation interference by multiplying the received digital signal sample with the obtained at least one model value to thereby obtain an output digital signal sample from which intermodulation interference, inflicted by the receiver, is cancelled.

18. A computer program product stored in a non-transitory computer readable medium for controlling a wireless communication node, the computer program product comprising software instructions which, when run on one or processors of the wireless communication node, causes the wireless communication node to:

receive a digital signal sample at a receiver;

obtain a power of the received digital signal sample;

obtain, based on the obtained power, at least one model value from a plurality of model values generated according to a model, wherein the model represents a non-linearity in amplitude and phase of a received signal that passes through passive and active components in the receiver, and wherein the plurality of model values correspond to a plurality of powers of the received signal;

cancel intermodulation interference by multiplying the received digital signal sample with the obtained at least one model value, thereby obtaining an output digital signal sample from which intermodulation interference, inflicted by the receiver, is cancelled.