Transmitter harmonic cancellation for carrier aggregation/multiband operation
View Patent ↗A method and apparatus for cancelling, from signals received by a radio device in a first frequency band, interference generated by the radio device in the first frequency band when the radio device transmits simultaneously radio signals on at least a second frequency band.
1. A method for cancelling, from signals received by a radio device in a first frequency band, interference generated by the radio device in the first frequency band when the radio device transmits simultaneously radio signals on at least a second frequency band, different from the first frequency band, the method comprising the following steps which cause the device to:
convert digital signals to be transmitted to analog signals to be transmitted in the second frequency band,
execute a first processing of the analog signals to be transmitted in the second frequency band, the first processing generating interference signals in the first frequency band due to non-linearity of the first processing,
execute a second processing at least on the interference signals generated in the first frequency band,
sense the interference signals in the first frequency band and convert the sensed interference in the first frequency band into digital samples of the interference,
apply to the digital signals to be transmitted a mathematical model that mimics the non-linearity of the first processing,
perform an adaptive filtering in order to provide digital samples for correction, wherein the adaptive filtering mimics the second processing and uses the digital samples of the interference and the digital samples on which the mathematical model is applied,
convert received analog signals in the first frequency band into digital received signals, and
cancel from the digital received signals the interference using the digital samples for correction.
2. The method according to claim 1 , further comprising:
transposing in frequency the digital samples on which the mathematical model is applied or the digital samples for correction.
3. The method according to claim 1 , further comprising:
adapting the amplitude and the delay of the digital samples for correction and/or of the digital received signals.
4. The method according to claim 3 , wherein the adapting of the amplitude and the delay comprises executing an adaptive filtering on the digital samples for correction and/or the digital received signals.
5. The method according to claim 1 , wherein the interference is sensed using a directive device.
6. The method according to claim 1 , wherein the first processing of the analog signals to be transmitted comprises amplifying the analog signals to be transmitted.
7. The method according to claim 1 , wherein the second processing on the signals generated in the first frequency comprises filtering the signals generated in the first frequency band by a filter with its pass band adapted for the second frequency band.
8. A radio receiving device for cancelling, from signals received by a radio device in a first frequency band, interference generated by the radio device in the first frequency band when the radio device transmits simultaneously radio signals on at least a second frequency band, different from the first frequency band, the device comprising a processor and circuitry causing the device to:
convert digital signals to be transmitted to analog signals to be transmitted in the second frequency band,
execute a first processing on the analog signals to be transmitted in the second frequency band, the first processing generating interference signals in the first frequency band due to non-linearity of the first processing,
execute a second processing at least on the interference signals generated in the first frequency band,
sense the interference signals in the first frequency band and convert the sensed interference in the first frequency band into digital samples of the interference,
apply to the digital signals to be transmitted a mathematical model that mimics the non-linearity of the first processing,
perform an adaptive filtering in order to provide digital samples for correction, wherein the adaptive filtering mimics the second processing and uses the digital samples of the interference and the digital samples on which the mathematical model is applied,
convert received analog signals in the first frequency band into digital received signals, and
cancel from the digital received signals the interference using the digital samples for correction.
9. The device according to claim 8 , further comprising circuitry causing the device to:
transpose in frequency the digital samples on which the mathematical model is applied or the digital samples for correction.
10. The device according to claim 9 , further comprising circuitry causing the device to:
adapt the amplitude and the delay of the digital samples for correction and/or of the digital received signals.
11. The device according to claim 10 , wherein the adapting of the amplitude and the delay of the digital samples comprises executing an adaptive filtering on the digital samples for correction and/or the digital received signals.
12. The device according to claim 8 , further comprising circuitry causing the device to sense the interference using a directive device.
13. The device according to claim 8 , wherein the circuitry for executing the first processing on the analog signals to be transmitted comprises an amplifier.
14. The device according to claim 8 , wherein the circuitry for executing the second processing on the signals generated in the first frequency band comprises a filter with its pass band adapted for the second frequency band.
15. A non-transitory computer-readable storage medium comprising a set of computer-readable instructions stored thereon, which, when executed by an apparatus which comprises a processor, causes the apparatus to implement the method according to claim 1 .