US 12,177,169 B2
Self-interference cancellation in frequency division duplexing system
Jin Yuan, Richardson, TX (US); Khurram Muhammad, Southlake, TX (US); and Gary Xu, Allen, TX (US)
Assigned to Samsung Electronics Co., Ltd., Suwon-si (KR)
Filed by Samsung Electronics Co., Ltd., Suwon-si (KR)
Filed on Jan. 5, 2021, as Appl. No. 17/142,116.
Claims priority of provisional application 63/057,118, filed on Jul. 27, 2020.
Prior Publication US 2022/0029774 A1, Jan. 27, 2022
Int. Cl. H04L 5/14 (2006.01); H03M 1/12 (2006.01); H04B 1/44 (2006.01); H04L 25/03 (2006.01)
CPC H04L 5/1461 (2013.01) [H04B 1/44 (2013.01); H04L 25/03012 (2013.01); H03M 1/12 (2013.01)] 14 Claims
OG exemplary drawing
 
1. A communication device comprising:
an antenna configured to receive a receive signal in a receive frequency band and transmit a transmit signal in a transmit frequency band;
transmit path circuitry configured to generate the transmit signal, the transmit path circuitry comprising a digital pre-distorter (DPD), a digital to analog converter (DAC), and a power amplifier (PA);
receive path circuitry configured to process the receive signal, the receive path circuitry including a first analog to digital converter (ADC) configured to convert the receive signal from an analog receive signal to a digital receive signal;
coupled path circuitry comprising a coupler, a band rejection filter, a second ADC, a first switch, a second switch, and a third switch; and
self-interference cancellation circuitry,
wherein the coupler is configured to couple a sample of the transmit signal to the first switch, the first switch is configured to connect the coupler switchably to an input of the band rejection filter and the second switch, the second switch is configured to connect an input of the second ADC switchably to the first switch and an output of the band rejection filter, the third switch is configured to connect an output of the second ADC switchably to the self-interference cancellation circuitry and the DPD, the band rejection filter is configured to reject frequencies in the transmit frequency band from the sample of the transmit signal to generate a filtered sample of the transmit signal, the second ADC is configured to convert the filtered sample of the transmit signal from an analog sample of the transmit signal to a digital sample of the transmit signal based on the second ADC being connected to the output of the band rejection filter and to the self-interference cancellation circuitry, and the second ADC is further configured to convert the sample of the transmit signal from an analog sample of the transmit signal to the digital sample of the transmit signal based on being connected to the first switch and to the DPD,
wherein the self-interference cancellation circuitry is configured to:
process the digital sample of the transmit signal that is output by the second ADC by equalizing the digital sample of the transmit signal to the digital receive signal to generate a self-interference cancellation signal; and
apply the self-interference cancellation signal to the digital receive signal that is output by the first ADC to cancel an amount of interference induced in the receive signal by the transmit signal, and
wherein the DPD is configured to generate a pre-distorted digital transmit signal based on the digital sample of the transmit signal, the DAC is configured to convert the pre-distorted digital transmit signal into a pre-distorted analog transmit signal, and the PA is configured to amplify the pre-distorted analog transmit signal to generate the transmit signal.