Angle of arrival estimation in a radio communications network

Patent metadata

Field	Value
Publication number	US-10333633-B2
Application number	US-201715531650-A
Country	US
Kind code	B2
Filing date	May 10, 2017
Priority date	May 10, 2017
Publication date	Jun 25, 2019
Grant date	Jun 25, 2019

Abstract

There is provided mechanisms for estimating angle of arrival of a radio signal in a radio communications network. A method is performed by a radio transceiver device. The radio transceiver device comprises an antenna array that, by means of analog beamforming, is configured to shift between at least two phase center locations. The method comprises obtaining measurements of the radio signal as received by the antenna array using two mutually different phase center locations. The method comprises estimating the angle of arrival of the radio signal using the measurements as obtained using the two mutually different phase center locations.

First claim

The invention claimed is:

1. A method for estimating angle of arrival of a radio signal in a radio communications network , the method being performed by a radio transceiver device comprising an antenna array that is configured to shift between at least two phase center locations, the method comprising:
obtaining measurements of the radio signal as received by the antenna array using two mutually different phase center locations of the antenna array, wherein obtaining the measurements comprises:
configuring the antenna array to have a first phase center location (p 1 ),
while the antenna array has the first phase center location, using the antenna array to obtain a first measurement of the radio signal,
configuring the antenna array to have a second phase center location (p 2 ) that is different than the first phase center location (p 1 ), and
while the antenna array has the second phase center location, using the antenna array to obtain a second measurement of the radio signal; and
estimating the angle of arrival of the radio signal using the first and second measurements as obtained using the first and second phase center locations of the antenna array.

2. The method of claim 1 , wherein the angle of arrival of the radio signal is estimated using a phase difference between the first measurement as obtained using the first phase center location (p 1 ) and the second measurement as obtained using the second phase center location (p 2 ).

3. The method of claim 1 , wherein the two mutually different phase center locations are separated at least by half a wavelength of an operating frequency of the received radio signal.

4. The method of claim 1 , wherein the antenna array comprises antenna elements, and wherein adjacent antenna elements are separated at least by half a wavelength of an operating frequency of the received radio signal.

5. The method of claim 1 , wherein the antenna array comprises antenna elements, wherein a first set of the antenna elements is used when the radio signal is received by the antenna array using one of the two mutually different phase center locations, wherein a second set of the antenna elements is used when the radio signal is received by the antenna array using the other of the two mutually different phase center locations, and wherein the second set is partly but not fully overlapping with the first set.

6. The method of claim 1 , wherein the antenna array comprises antenna elements, and wherein the antenna array is configured to shift between the at least two phase center locations by selectively switching on and off at least one of the antenna elements.

7. The method of claim 6 , wherein at least one of the antenna elements is configured to be selectively switched on and off by selectively switching on and off a low-noise amplifier, an attenuator, or a switch of said at least one of the antenna elements.

8. The method of claim 6 , wherein the antenna elements have two mutually orthogonal polarizations, and wherein both orthogonal polarizations are simultaneously switched on and off as the at least one of the antenna elements is selectively switched on and off.

9. The method of claim 1 , wherein the antenna array comprises antenna elements, and wherein the antenna array is configured to shift between the at least two phase center locations by selectively increasing and reducing gain of a low-noise amplifier of at least one of the antenna elements.

10. The method of claim 1 , wherein the antenna array is configured to simultaneously receive the radio signals in two mutually orthogonal polarizations.

11. The method of claim 10 , wherein one intermediate value of the angle of arrival is estimated for each of the two mutually orthogonal polarizations, and wherein the angle of arrival is estimated using a combination of the intermediate values.

12. The method of claim 1 , wherein the antenna array comprises antenna elements, and wherein the radio signal for each one of the two mutually different phase center locations is received in at least one receive beam being created by the analog beamforming in the antenna array only using phase shifts of those of the antenna elements that are used to create the at least one receive beam.

13. The method according of claim 1 , wherein the antenna array comprises antenna elements, and wherein the radio signal for each one of the two mutually different phase center locations is received in at least one receive beam being created by the analog beamforming in the antenna array using a combination of phase shifts and amplitude tapering of those of the antenna elements that are used to create the at least one receive beam.

14. The method of claim 1 , wherein the radio signal is received by the antenna array using a first of the two mutually different phase center locations in a first time slot and a second of the two mutually different phase center locations in a second time slot.

15. The method of claim 1 , wherein each measurement of the radio signal corresponds to either one whole or a fraction of an orthogonal frequency-division multiplexing, OFDM, symbol such that one whole or one fraction of the OFDM symbol on which a respective one of the measurements is based is received using each one of the two mutually different phase center locations.

16. The method of claim 1 wherein the antenna array is a two-dimensional antenna array, and wherein the angle of arrival is simultaneously estimated in both dimensions.

17. The method of claim 1 , wherein the radio signal is received from another radio transceiver device, the method further comprising:
communicating with said another radio transceiver device in a beam, the beam pointing in a direction selected according to the angle of arrival.

18. A radio transceiver device for estimating angle of arrival of a radio signal in a radio communications network , the radio transceiver device comprising an antenna array that is configured to shift between at least two phase center locations, the radio transceiver device further comprising processing circuitry, the processing circuitry being configured to cause the radio transceiver device to:
obtain measurements of the radio signal as received by the antenna array using two mutually different phase center locations of the antenna array,
wherein the radio transceiver device is configured to obtain the measurements by performing a process that includes:
configuring the antenna array to have a first phase center location (p 1 ),
while the antenna array has the first phase center location, using the antenna array to obtain a first measurement of the radio signal,
configuring the antenna array to have a second phase center location (p 2 ) that is different than the first phase center location (p 1 ), and
while the antenna array has the second phase center location, using the antenna array to obtain a second measurement of the radio signal; and
estimate the angle of arrival of the radio signal using the first and second measurements as obtained using the first and second phase center locations of the antenna array.

19. The radio transceiver device of claim 18 , wherein the radio transceiver device is a radio access network node.

20. A computer program product comprising a non-transitory computer readable medium storing a computer program for estimating angle of arrival of a radio signal in a radio communications network , the computer program comprising computer code which, when run on processing circuitry of a radio transceiver device comprising an antenna array that, by

Assignees

• Ericsson Telefon Ab L M

Inventors

• Petersson Sven
• Athley Fredrik
• Nilsson Andreas

Classifications

• H04W72/51

  based on terminal or device properties · CPC title

• H04B7/086

  using weights depending on external parameters, e.g. direction of arrival [DOA], predetermined weights or beamforming · CPC title

• H01Q3/267

  Phased-array testing or checking devices · CPC title

• G01S3/48 Primary

  the waves arriving at the antennas being continuous or intermittent and the phase difference of signals derived therefrom being measured · CPC title

• G01S3/04

  Details · CPC title