Switchable transmission line structure for digital pre-distortion (DPD) in millimeter wave phased array environment
Described herein are systems with switchable circuitry configured to selectively couple transmitter outputs to processing hardware, which may selectively route subsets of distortion measurements from transmitters for DPD processing that compensates for the measured distortion. The switchable nature of the distortion measurement propagation paths permits the paths to be made substantially shorter than static paths, resulting in improved (e.g., reduced and/or more uniform) attenuation and/or phase change across a transceiver array. In one example, measurement propagation paths may be no longer than a row or column of the array. In some embodiments, systems described herein may be suitable for implementation at mmW transmit and/or receive frequencies, where the length of measurement paths may have a significant impact on attenuation and phase changes.
1. A transceiver system, comprising:
a plurality of transmitters configured to operate in at least one frequency band in a range from 10 GHz to 300 GHz, each transmitter comprising circuitry configured to obtain a distortion measurement of the transmitter; and
a switch network controllable to selectively couple at least one of the distortion measurements of the plurality of transmitters to a processor;
wherein the switch network is controllable between, at least:
a first state, in which the switch network is configured to couple the circuitry of a first transmitter of the plurality of transmitters to the processor and to decouple the circuitry of a second transmitter of the plurality of transmitters from the processor; and
a second state, in which the switch network is configured to couple the circuitry of the second transmitter to the processor and to decouple the circuitry of the first transmitter from the processor;
wherein:
in the first state, the switch network is further configured to couple a first group of transmitters of the plurality of transmitters, including the first transmitter and a third transmitter, to the processor and to decouple a second group of transmitters of the plurality of transmitters, including the second transmitter and a fourth transmitter, from the processor; and
in the second state, the switch network is further configured to couple the second group of transmitters to a receive beamformer and to decouple the first group of transmitters from the processor.
2. The transceiver system of claim 1 , wherein the plurality of transmitters are configured to operate in at least one frequency band within a range from 24 GHz to 71 GHz.
3. The transceiver system of claim 1 , further comprising:
the processor, wherein the processor is a baseband processor configured to use the at least one of the distortion measurements to perform digital pre-distortion (DPD) processing on signals to be transmitted via the plurality of transmitters,
wherein the switch network is coupled to the processor.
4. The transceiver system of claim 1 , wherein the circuitry of each of the plurality of transmitters comprises a directional coupler having an input coupled to an output of the transmitter and an output coupled to the switch network.
5. The transceiver system of claim 1 , wherein each transmitter of the plurality of transmitters comprises an amplifier and the circuitry is configured to obtain the distortion measurement from an output of the amplifier.
6. A phased array system, comprising:
the transceiver system of claim 1 ; and
a plurality of antennas coupled to the plurality of transmitters, respectively, and configured to transmit and/or receive signals in the at least one frequency band.
7. The phased array system of claim 6 , further comprising:
a receive beamformer comprising a summing circuit and a demodulator configured to receive signals via the plurality of antennas,
wherein the switch network is configured to provide distortion measurements of the plurality of transmitters to the processor via the summing circuit and/or the demodulator.
8. A transceiver system, comprising:
a plurality of transceivers arranged in a plurality of groups of at least one transceiver, each transceiver comprising a transmit amplifier and a coupler coupled to an output of the transmit amplifier;
a plurality of switches, each switch configured to be coupled between a processor and at least one coupler of a respective group of at least one transceiver of the plurality of groups of at least one transceiver;
a plurality of antennas coupled to the plurality of transceivers and configured to transmit and/or receive signals; and
receive beamforming circuitry comprising summing circuitry configured to sum signals received via the plurality of antennas and demodulation circuitry configured to down-convert a frequency of signals received via the plurality of antennas, the plurality of switches coupled between the summing circuitry and the respective couplers and/or between the demodulation circuitry and the respective couplers.
9. The transceiver system of claim 8 , wherein:
the couplers are configured to obtain distortion measurements from the outputs of the transmit amplifiers, respectively; and
the plurality of switches are configured to provide the distortion measurements to the processor.
10. The transceiver system of claim 9 , further comprising:
the processor, wherein the processor is a baseband processor configured to use the distortion measurements to perform digital pre-distortion (DPD) processing on signals to be transmitted via the plurality of transceivers,
wherein each switch is coupled between the processor and the at least one coupler of the respective group of at least one transceiver of the plurality of groups of at least one transceiver.
11. The transceiver system of claim 8 , wherein the plurality of switches comprises:
a first switch configured to be coupled between the processor and a first coupler of a first group of at least one transceiver of the plurality of groups of at least one transceiver; and
a second switch configured to be coupled between the processor and a second coupler of a second group of at least one transceiver of the plurality of groups of at least one transceiver.
12. The transceiver system of claim 8 , wherein the couplers are directional couplers, each directional coupler having an input coupled to an output of a respective transmit amplifier of the plurality of transceivers and an output coupled to the plurality of switches.
13. The transceiver system of claim 8 , wherein the plurality of transceivers are configured to operate in at least one frequency band within a range from 24 GHz to 71 GHz.
14. A phased array system, comprising:
a transceiver system, comprising:
a plurality of transceivers arranged in a plurality of groups of at least one transceiver, each transceiver comprising a transmit amplifier and a coupler coupled to an output of the transmit amplifier; and
a plurality of switches, each switch configured to be coupled between a processor and at least one coupler of a respective group of at least one transceiver of the plurality of groups of at least one transceiver; wherein the plurality of switches comprises a first switch and a second switch; the first switch is configured to be coupled between the processor and a first coupler of a first group of at least one transceiver of the plurality of groups of at least one transceiver, and the second switch configured to be coupled between the processor and a second coupler of a second group of at least one transceiver of the plurality of groups of at least one transceiver;
an antenna array arranged in a first dimension and a second dimension, the antenna array comprising:
a first group of antennas disposed along the first dimension; and
a second group of antennas disposed along the first dimension and spaced from the first group of antennas in the second dimension,
wherein:
the first group of at least one transceiver comprises a first plurality of transceivers respectively coupled to the first group of antennas; and
the second group of at least one transceiver comprises a second plurality of transceivers respectively coupled to the second group of antennas.
15. The phased array system of claim 14 , wherein:
the first switch is configured to be coupled between each coupler of the first plurality of transceivers and the processor; and
the second switch is configured to be coupled between each coupler of the second plurality of transceivers and the processor.
16. The phased array system of claim 15 , wherein the plurality of switches comprises a third switch coupled between the first switch and the second switch.