Communication unit, integrated circuit and method for generating a plurality of sectored beams

• US 10,193,603 B2
• Filed: 08/15/2014
• Issued: 01/29/2019
• Est. Priority Date: 08/16/2013
• Status: Active Grant

• Current Assignee: Analog Devices International Unlimited Company (Analog Devices, Inc.)
• Original Assignee: Analog Devices Global Unlimited Company (Analog Devices, Inc.)
• Inventors: O'Keeffe, Conor, O'Brien, Michael, Sexton, Sean
• Primary Examiner(s): Nawaz, Asad M
• Assistant Examiner(s): Chang, Kai
• Application Number:
  US14/912,057
• Publication Number:
  US 20160197660A1
• Time in Patent Office: 1,628 Days
• CPC Class Codes: H01Q 1/246 specially adapted for base stations
• CPC Class Codes: H01Q 3/267 Phased-array testing or checking devices
• CPC Class Codes: H04B 17/11 for calibration
• CPC Class Codes: H04B 17/12 of transmit antennas, e.g. of the amplitude or phase
• CPC Class Codes: H04B 17/14 of the whole transmission and reception path, e.g. self-test loop-back
• CPC Class Codes: H04B 7/0408 using two or more beams, i.e. beam diversity
• CPC Class Codes: H04B 7/0491 using two or more sectors, i.e. sector diversity
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04W 16/28 using beam steering

Abstract

A communication unit comprises a plurality of antenna element feeds (203, 205) for coupling to a plurality of antenna elements of an antenna array, where each antenna element feed comprises at least one coupler; and a plurality of transmitters operably coupled to the plurality of antenna element feeds. At least one transmitter of the plurality of transmitters comprises: an input for receiving a first signal and at least one second signal; beamformer logic arranged to apply independent beamform weights (RefBF1, RefBF2) on the first signal and the at least one second signal of the transmitter respectively, wherein each of the independent beamform weights is allocated on a per sector basis; and a signal combiner arranged to combine the first signal and the second signal to produce a combined signal, such as that the combined signal supports a plurality of sectored beams.

Claims

1. A communication unit for generating a plurality of sectored beams, the communication unit comprising:

a plurality of antenna element feeds arranged to couple to a plurality of antenna elements of an antenna array, wherein an individual antenna element feed of the plurality of antenna element feeds is configured to provide a transmit signal associated with two sectors;

a plurality of transmitters operably coupled to the plurality of antenna element feeds;

wherein a transmitter of the plurality of transmitters is configured to receive a first signal associated with a first sector and a second signal associated with a second sector, the two sectors comprising the first sector and the second sector, and the transmitter comprises;

beamformer logic arranged to apply independent beamform weights on the first signal and the second signal of the transmitter to generate a weighted first signal and a weighted second signal, respectively, wherein each of the independent beamform weights is allocated on a per sector basis; and

a signal combiner arranged to combine the weighted first signal and the weighted second signal to produce a combined signal such that the combined signal supports sectored beams for the two sectors, wherein an output of the signal combiner is operably coupled to the individual antenna element feed, and

wherein the beamformer logic is configured to apply a calibration correction coefficient so as to calibrate an amplitude and a phase of the combined signal.

2. The communication unit of claim 1 further comprising a signal processor operably coupled to beamformer logic and arranged to concurrently process a transmission of sectored beams for the two sectors applied to antenna element feeds of the plurality of antenna elements.

3. The communication unit of claim 1 wherein the beamformer logic is arranged to apply the independent beamform weights such that beams associated with the two sectors are transmitted on the same carrier frequency or in an overlapping occupied spectrum.

4. The communication unit of claim 1 wherein the antenna array is configured to support the two sectors on a single carrier frequency using at least the individual antenna element feed.

5. The communication unit of claim 1 further comprising a frequency converter operably coupled to the signal combiner and arranged to frequency-convert the combined signal and route the frequency-converted combined signal to the individual antenna element feed to support the sectored beams for the two sectors.

6. The communication unit of claim 1 further comprising a Crest Factor Reduction signal processing block arranged to apply crest factor reduction to the combined signal.

7. The communication unit of claim 1 wherein the calibration correction coefficient is normalised for the transmitter against a reference transmitter.

8. The communication unit of claim 1 wherein the transmitter comprises a complex multiplier operatively coupled to an output of the signal combiner, the complex multiplier configured to scale the combined signal at baseband using the calibration correction coefficient.

9. The communication unit of claim 1 wherein one or more complex multipliers are arranged to apply the independent beamform weights and the calibration correction coefficient.

10. The communication unit of claim 1 wherein the beamformer logic is arranged to apply the independent beamform weights on the first signal and the second signal to provide beam sectorisation in at least one of a vertical plane or a horizontal plane.

11. The communication unit of claim 10 wherein the beam sectorisation comprises a first sectored beam at a first power and a second sectored beam at a different second power.

12. The communication unit of claim 10 wherein the beam sectorisation comprises a first sectored beam at a first beamwidth and a second sectored beam at a different second beamwidth.

13. The communication unit of claim 1 wherein the beamformer logic is configured to apply the calibration correction coefficient in a digital domain.

14. An integrated circuit for a transmitter configured to support sectored beams, the integrated circuit comprising:

beamformer logic arranged to apply independent beamform weights on a first signal and a second signal to generate a weighted first signal a weighted second signal, respectively, wherein each of the independent beamform weights is allocated on a per sector basis; and

a signal combiner arranged to combine the weighted first signal and the weighted second signal to produce a combined signal such that the combined signal supports a plurality of sectored beams for transmission, wherein the beamformer logic is configured to apply a calibration correction coefficient so as to calibrate an amplitude and a phase of the combined signal.

15. The integrated circuit of claim 14 wherein a complex multiplier is configured to scale the combined signal at baseband using the calibration correction coefficient.

16. The integrated circuit of claim 14 wherein two or more complex multipliers are arranged to apply the independent beamform weights and the calibration correction coefficient.

17. A method for generating sectored beams with an antenna array that comprises a plurality of antenna element feeds for coupling a plurality of respective transmitters to a plurality of antenna elements via respective coupler ports, the method comprising:

applying independent beamform weights on the first signal of a first transmitter of the plurality of transmitters and a second signal of the first transmitter to generate a weighted first signal and a weighted second signal, respectively, wherein each of the independent beamform weights is allocated on a per sector basis;

combining the weighted first signal and the weighted second signal to produce a combined signal associated with sectored beams for two sectors;

applying a calibration correction coefficient to calibrate an amplitude and a phase of the combined signal; and

generating the sectored beams for the two sectors such that an individual antenna element of the plurality of antenna elements transmits a transmit signal associated with the two sectors, wherein the transmit signal is generated based on said applying the calibration correction coefficient to calibrate the amplitude and the phase of the combined signal.

18. The method of claim 17 further comprising:

normalising the calibration correction coefficient relative to at least one other transmitter of the plurality of transmitters; and

effecting an adjustment of at least one parameter on the first transmitter in response to said normalising.

19. The method of claim 18 wherein normalising the calibration correction coefficient relative to the first transmitter comprises normalising the at least one calibration correction coefficient relative to a transmitter of the plurality of transmitters that is determined as having the longest latency.

20. The method of claim 17 wherein applying the calibration correction coefficient is performed in a digital domain.