Reducing intermodulation distortion for intra-band dual connectivity
A radio frequency front end (RFFE) is configured to support dual connectivity communications, in which two different radio access technologies such as 4 th -Generation (4G) Long-Term Evolution (LTE) and 5 th -Generation (5G) New Radio (NR) data connections are used simultaneously for communications between a wireless communication device and respective LTE and NR base stations. In described embodiments, the RFFE uses two power amplifiers to reduce intermodulation distortion (IMD). The two power amplifiers produce output signals for a 4G LTE uplink and a 5G NR uplink, respectively. The RFFE also has a combiner that mixes the output signals to produce a composite output signal representing both LTE and NR data. Bypass switches may be used to configure the RFFE so that it can be used for single conventional 4G LTE communications.
1. A radio frequency (RF) front end for use in a cellular communication device, comprising:
a signal splitter to separate a received RF input signal from an antenna to produce a first RF input signal and a second RF input signal in a dual-connectivity mode, wherein the first RF input signal represents first downlink data of a downlink data stream in accordance with a first radio access technology and the second RF input signal represents second downlink data of the downlink data stream in accordance with a second radio access technology;
a first amplifier coupled to a first output of the signal splitter;
a second amplifier coupled to a second output of the signal splitter; and
one or more RF switches to selectively send the received RF input signal to the signal splitter in the dual-connectivity mode and to one of the first amplifier or the second amplifier in a non-dual-connectivity mode.
2. The radio frequency front end of claim 1 , wherein the first radio access technology comprises a 4th-Generation (4G) radio access technology and the second radio access technology comprises a 5th-Generation (5G) radio access technology.
3. The radio frequency front end of claim 2 , wherein the first RF input signal is a Long-Term Evolution (LTE) signal and the second RF input signal is a New Radio (NR) signal.
4. The radio frequency front end of claim 1 , wherein:
the first RF input signal is associated with a first frequency;
the second RF input signal is associated with a second frequency; and
the first frequency and the second frequency are within a band of frequencies that are designated for cellular device communications in the dual-connectivity mode.
5. The radio frequency front end of claim 1 , wherein the one or more RF switches comprises a first RF switch coupled between the antenna and the signal splitter and a second RF switch coupled between the signal splitter and one of the first amplifier or the second amplifier.
6. The radio frequency front end of claim 1 , further comprising a duplexer to connect a composite RF output signal for transmission by the antenna and to provide the received RF input signal to the signal splitter.
7. The radio frequency front end of claim 1 , further comprising:
a third amplifier to amplify a first RF output signal to create a first amplified RF output signal, wherein the first RF output signal represents a first portion of an uplink data in accordance with the first radio access technology; and
a fourth amplifier to amplify a second RF output signal to create a second amplified RF output signal, wherein the second RF output signal represents a second portion of the uplink data in accordance with the second radio access technology.
8. A cellular communication device, comprising:
an antenna receiving a composite radio frequency (RF) input signal comprising a first portion of downlink data communicated according to a first radio access technology and a second portion of the downlink data communicated according to a second radio access technology in a dual-connectivity operation;
baseband-RF circuitry converting the first portion of the downlink data and the second portion of the downlink data into an aggregated downlink digital stream, and converting an uplink digital stream into a first RF output signal according to the first radio access technology and a second RF output signal according to the second radio access technology;
a first amplifier amplifying the first RF output signal into a first amplified RF output signal; and
a second amplifier separately amplifying the second RF output signal into a second amplified RF output signal.
9. The cellular communication device of claim 8 , wherein the first radio access technology comprises a 4th-Generation (4G) radio access technology and the second radio access technology comprises a 5th-Generation (5G) radio access technology.
10. The cellular communication device of claim 8 , wherein:
the first RF output signal is associated with a first frequency;
the second RF output signal is associated with a second frequency; and
the first frequency and the second frequency are within a band of frequencies that are designated for the dual-connectivity operation.
11. The cellular communication device of claim 8 , further comprising a signal combiner mixing the first amplified RF output signal and the second amplified RF output signal to provide a composite RF output signal for transmission by the antenna in the dual-connectivity operation, wherein the first amplified RF output signal represents first uplink data in accordance with the first radio access technology and the second amplified RF output signal represents second uplink data in accordance with the second radio access technology.
12. The cellular communication device of claim 11 , further comprising a duplexer that (a) provides the composite RF output signal for transmission by the antenna and (b) receives the composite RF input signal from the antenna.
13. The cellular communication device of claim 11 , further comprising an RF splitter separating the composite RF input signal received by the antenna into a first RF input signal and a second RF input signal, wherein the first RF input signal represents the first portion of the downlink data in accordance with the first radio access technology and the second RF input signal represents the second portion of the downlink data in accordance with the second radio access technology.
14. The cellular communication device of claim 8 , further comprising one or more RF switches, between the antenna and an RF splitter, selectively bypassing the RF splitter with the composite RF input signal.
15. A method performed by a cellular communication device, comprising:
receiving a composite radio frequency (RF) input signal comprising a downlink data stream;
splitting the composite RF input signal into (a) a first RF input signal representing a first portion of the downlink data stream in accordance with a first radio access technology and (b) a second RF input signal representing a second portion of the downlink data stream in accordance with a second radio access technology;
converting the first RF input signal and the second RF input signal into an aggregated downlink data stream at baseband;
converting an uplink data stream at baseband into a first RF output signal in accordance with the first radio access technology and a second RF output signal at the second radio access technology; and
separately amplifying the first RF output signal and the second RF output signal to produce a first amplified RF output signal and a second amplified RF output signal.
16. The method of claim 15 , wherein:
the first RF input signal is associated with a first frequency;
the second RF input signal is associated with a second frequency; and
the first frequency and the second frequency are within a band of frequencies that are designated for non-standalone cellular device communications.
17. The method of claim 15 , wherein the first radio access technology comprises a 4th-Generation (4G) radio access technology and the second radio access technology comprises a 5th-Generation (5G) radio access technology.
18. The method of claim 15 , wherein the first RF input signal in accordance with the first radio access technology is received from a first base station and the second RF input signal in accordance with the second radio access technology is received from a second base station.
19. The method of claim 15 , further comprising combining the first amplified RF output signal and the second amplified RF output signal to create a composite RF output signal.
20. The method of claim 19 , further comprising concurrently producing (a) the first RF output signal representing a first portion of the uplink data stream and (b) the second RF output signal representing a second portion of the uplink data stream.