Reconfigurable hybrid beamforming MIMO receiver with inter-band carrier aggregation and RF-domain LMS weight adaptation
A reconfigurable, multi-band hybrid beamforming architecture is introduced. The present invention is related to a Cartesian-Combining architecture to efficiently implement RF beamforming for a single downconversion chain employing direct downconversion in which the Cartesian-Combining architecture is extended to hybrid beamforming and to heterodyne downconversion.
1. A fully-connected hybrid beamforming receiver comprising:
a. circuitry implementing one or more low noise amplifiers, each coupled to an antenna, each low-noise amplifier outputting one or more streams;
b. circuitry, for applying complex weighting to each of the one or more streams;
c. circuitry implementing a multi-stage combiner, for combining one stream from each of the one or more low noise amplifiers to produce a combined stream; and
d. circuitry implementing one or more two-stage mixers, per the combined stream, and one mixer per stage, a first stage for performing a heterodyne downconverting of the combined stream to an intermediate frequency using a signal generated by a first local oscillator and a second stage for performing a heterodyne downconverting of each combined stream at the intermediate frequency to a baseband frequency using a signal generated by a second local oscillator.
2. The receiver of claim 1 wherein each of the one or more low noise amplifiers comprises a concurrent dual-band low noise amplifier.
3. The receiver of claim 1 wherein each of the one or more low noise amplifiers comprises a contiguously wideband low noise amplifier.
4. The receiver of claim 1 wherein the circuitry for applying complex weighting comprises:
a. a variable gain amplifier; and
b. a phase shifter.
5. The receiver of claim 4 wherein the variable gain amplifier is controlled by an analog voltage or a digital code.
6. The receiver of claim 4 wherein the variable gain amplifier is controlled by an analog voltage or current.
7. The receiver of claim 4 , the phase shifter having a gain, wherein the gain of the phase shifter is controlled by an analog voltage or current.
8. The receiver of claim 4 , the phase shifter having a gain, wherein the gain of the phase shifter is controlled by a digital code.
9. The receiver of claim 1 wherein the circuitry for applying complex weighting comprises:
a. a pair of variable gain amplifiers; and
b. a downconverter.
10. The receiver of claim 9 wherein the gain of the variable gain amplifiers is controlled by an analog voltage or current.
11. The receiver of claim 9 wherein the gain of the variable gain amplifiers is controlled by a digital code.
12. The receiver of claim 1 wherein the signal generated by the second local oscillator is derived from the signal generated by the first local oscillator.
13. The receiver of claim 5 wherein each of the one or more streams comprises a real and an imaginary component.
14. The receiver of claim 9 wherein the second stage of the one or more two-stage mixers performs image rejection.
15. The receiver of claim 9 wherein the first stage of the one or more two-stage mixers performs simple downconversion of the combined stream to the intermediate frequency and further wherein the second stage of the one or more two-stage mixers performs downconversion of the combined stream to the baseband frequency.
16. The receiver of claim 9 wherein the first stage of the one or more two-stage mixers performs quadrature downconversion of the combined stream to the intermediate frequency and combines the real and imaginary components of the stream into a combined signal and further wherein the second stage of the one or more two-stage mixers performs quadrature downconversion of the combined signal to the baseband frequency.
17. The receiver of claim 9 wherein the first stage of the one or more two-stage mixers performs downconversion of the combined stream to the intermediate frequency and further wherein the second stage of the one or more two-stage mixers performs simple downconversion of the combined stream to the baseband frequency.