COMMUNICATION UNIT, INTEGRATED CIRCUIT AND METHOD FOR GENERATING A PLURALITY OF SECTORED BEAMS

• US 20160197660A1
• Filed: 08/15/2014
• Published: 07/07/2016
• 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
• Granted Patent: US 10,193,603 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 (RcfBF1, RcfBF2) 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 comprising:

a plurality of antenna element feeds arranged to couple to a plurality of antenna elements of an antenna array;

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

wherein at least one transmitter of the plurality of transmitters comprises;

at least one input configured to receive a first signal and at least one second signal;

beamformer logic arranged to apply independent beamform weights on the first signal and the at least one 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 a plurality of sectored beams, wherein the beamformer logic is configured to apply a calibration correction coefficient so as to calibrate 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 a plurality of sector beams applied to at least one antenna element feed of the plurality of antenna elements.

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

4. The communication unit of claim 1 wherein a single antenna array of an active antenna system is configured to support multiple sectors on at least one carrier frequency.

5. The communication unit of claim 4 wherein the single antenna array of the active antenna system is configured to support multiple sectors on a single carrier frequency using at least one common antenna element.

6. 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 plurality of the antenna elements to support the plurality of sectored beams.

7. 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.

8. The communication unit of claim 1 wherein the calibration correction coefficient is normalised for the at least one transmitter against a reference transmitter.

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

10. 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.

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

12. The communication unit of claim 11 wherein the beam sectorisation for at least two beams comprises a first sectored beam at a first power and a second sectored beam at a different second power.

13. The communication unit of claim 11 wherein the beam sectorisation for at least two beams comprises a first sectored beam at a first beamwidth and a second sectored beam at a different second beamwidth.

14. The communication unit claim 11 wherein the beam sectorisation for at least two beams comprises weights to provide a first sectored beam at a first direction and a second sectored beam at a different second direction.

15. An integrated circuit comprising:

at least one input configured to receive a first signal and at least one second signal;

beamformer logic arranged to apply independent beamform weights on the first signal and the at least one second signal to generate a weighted first signal and at least one 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 at least one weighted second signal to produce a combined signal such that the combined signal supports a plurality of sectored beams, wherein the beamformer logic is configured to apply a calibration correction coefficient so as to calibrate the combined signal.

16. A method for generating a plurality of sectored beams in 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 a first signal and at least one second signal to a first transmitter of the plurality of transmitters;

applying independent beamform weights on the first signal and the at least one second signal of the first transmitter to generate a weighted first signal and at least one 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 at least one weighted second signal to produce a combined signal, such that the combined signal supports a plurality of sectored beams; and

applying a calibration correction coefficient to calibrate the combined signal.

17. The method of claim 16 further comprising:

reading the calibration correction coefficient, wherein the calibration coefficient is associated with the first transmitter;

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.

18. The method of claim 17 wherein normalising the at least one 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.

19. The method of claim 16 further comprising providing beam sectorisation in at least one of:

a vertical plane;

a horizontal plane;

a first sectored beam at a first power and a second sectored beam at a different second power;

or a first sectored beam at a first beamwidth and a second sectored beam at a different second beamwidth.

20. A non-transitory computer program product comprising program code for generating a plurality of sectored beams in an antenna array that comprises a plurality of antenna elements coupled to a plurality of respective transmitters via respective coupler ports, the computer program product comprising program code operable to, when executed at a communication unit, perform the method of claim 16.