MIMO ANTENNA CALIBRATION DEVICE, INTEGRATED CIRCUIT AND METHOD FOR COMPENSATING PHASE MISMATCH

• US 20130235962A1
• Filed: 11/15/2011
• Published: 09/12/2013
• Est. Priority Date: 11/17/2010
• Status: Active Grant

• Current Assignee: Analog Devices International Unlimited Company (Analog Devices, Inc.)
• Original Assignee: Socowave Technologies Ltd
• Inventors: O'Brien, Michael, O'Keefe, Conor
• Granted Patent: US 9,628,256 B2
• Time in Patent Office: Days
• US Class Current: 375/371
• CPC Class Codes: H01Q 3/267 Phased-array testing or checking devices
• CPC Class Codes: H04B 17/12 of transmit antennas, e.g. of the amplitude or phase
• CPC Class Codes: H04B 17/21 for calibration; for correcting measurements
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity
• CPC Class Codes: H04L 7/0016 correction of synchronization errors

Abstract

A multiple input multiple output (MIMO) calibration device (360) for calibrating a phase relationship between at least two signals present on at least two radio frequency (RF) paths coupling a wireless communication unit and the MIMO calibration device (360) is described. The MIMO calibration device (360) is operably coupleable via at least two RF paths between a wireless communication unit and an antenna arrangement (219). The calibration device (360) comprises a processing module (490) configured to: process a coupled amount of at least one first signal from a first path operably coupleable to a first polarisation of the antenna arrangement (219) to determine at least one pilot signal from said at least one first signal; process a coupled amount of at least one second signal from a second path operably coupleable to at least one second polarisation feed of antenna arrangement (219), different to the first polarisation, to determine the at least one pilot signal from said at least one second signal; and determine a first phase relationship of the same pilot signal between the at least two RF paths.

Claims

1. A multiple input multiple output (MIMO) calibration device for calibrating a phase relationship between at least two signals present on at least two radio frequency (RF) paths coupling a wireless communication unit and the MIMO calibration device, wherein the MIMO calibration device is operably coupleable via at least two RF paths between a wireless communication unit and an antenna arrangement;

wherein the MIMO calibration device comprising;

a processing module configured to;

process a coupled amount of at least one first signal from a first path operably coupleable to a first polarization of the antenna arrangement to determine at least one pilot signal from said at least one first signal;

process a coupled amount of at least one second signal from a second path operably coupleable to at least one second polarization feed of antenna arrangement, different to the first polarization, to determine the at least one pilot signal from said at least one second signal; and

determine a first phase relationship of the same pilot signal between the at least two RF paths.

2. The MIMO calibration device of claim 1, wherein the at least one first signal is processed by at least one from a group comprising:

a virtual antenna mapping (VAM) module, a 3 dB hybrid combiner.

3. The MIMO calibration device of claim 1, wherein the at least one pilot signal comprises at least one from a group comprising:

a CPICH signal, a primary signaling channel (P-SCH) signal, a secondary signaling channel (S-SCH) signal, a synchronization signal, a tonal signal, an intermittently transmitted signal, a high speed downlink packet access signal (HSPA+).

4. The MIMO calibration device of claim 3, wherein the processing module is configured to determine from a P-SCH protocol signal at least one from a group comprising:

a frame boundary, a slot boundary.

5. The MIMO calibration device of claim 3, wherein the at least one pilot signal is a P-SCH signal and the MIMO calibration device uses at least one from a group comprising:

(i) a least mean square (LMS) adaptive filter to determine the phase relationship;

(ii) the P-SCH as a code used for automatic frequency correction (AFC) and phase relationship determination.

6. The MIMO control device of claim 1, wherein the processing module is further configured to:

receive and process a coupled amount of at least one first RF signal; and

determine at least one second phase relationship of the same pilot signal between the at least two RF paths to the antenna arrangement of the processed coupled amount of the at least one first RF signal

7. The MIMO calibration device of claim 1, wherein the MIMO calibration device comprises or is operably coupleable to at least one phase shifter module located on at least one path associated with one of the at least two RF paths such that the at least one phase shifter module is arranged to adjust a phase shift based on at least one determined phase relationship.

8. The MIMO calibration device of claim 7, wherein the at least one phase shifter module is operably coupleable to a motor such that the processing module configures the motor to adjust a phase shift (‘

β

’

) to be applied by the at least one phase shifter to RF signals passing there through.

9. The MIMO calibration device of claim 8, wherein the at least one phase shifter module is located on each of the at least two RF feed paths such that the processing module adjusts a phase shift (‘

β

’

) to be applied by the at least one variable phase shifter to RF signals passing through either or both of the at least two RF feed paths.

10. The MIMO calibration device of claim 1, wherein at least one determined phase relationship is communicated to another network element to control an incoming phase relationship of the at least one pilot signal determined from at least one first signal and at least one second signal on respective polarization feeds of the antenna arrangement.

11. The MIMO calibration device of claim 2, wherein the VAM module comprises a plurality of cross-coupled complex multipliers and summation modules capable of changing a phase of at least one signal operably coupleable to at least one polarization feed to antenna arrangement based on at least one determined phase relationship.

12. The MIMO calibration device of claim 1, further comprising or operably coupleable to a scanner for performing a scanning operation to determine a carrier frequency of the at least first signal and the at least one second signal by sequentially processing a coupled amount of predefined spectrum to determine a presence of the at least one pilot signal on first path and the second path for the same carrier frequency.

14. The MIMO calibration device of claim 1, wherein the MIMO calibration device further comprises a memory included within or coupled to the processing module and configured to store data samples to determine at least the first phase relationship in subsequent processing.

15. The MIMO calibration device of claim 1, wherein the MIMO calibration device is located in at least one from a group consisting of:

in the wireless communication unit, in antenna housing, between the wireless communication unit and the antenna such as at an antenna mast or at an antenna tower top.

16. The MIMO calibration device of claim 1, further comprising a feedback path configured to provide at least one determined phase relationship of the same pilot signal between the at least two RF paths to the wireless communication unit.

18. The MIMO calibration device of claim 1, wherein the processing module is further arranged to use a first representation of the at least one pilot signal as a reference signal to mitigate mismatch error on the second representation of the at least one pilot signal.

20. The MIMO calibration device of claim 1, wherein the processing module is further configured to:

determine the first phase relationship of the same pilot signal between the at least two RF paths between a baseband portion of the wireless communication unit and the MIMO calibration device;

determine a second phase relationship between the MIMO calibration device and the antenna; and

determine at least one composite phase correction value based on the first and second determination.

13. (canceled)

17. (canceled)

19. (canceled)

21. (canceled)

22. An integrated circuit for a multiple input multiple output (MIMO) calibration device for calibrating a phase relationship between two signal paths, wherein the MIMO calibration device is operably coupleable via at least two radio frequency (RF) paths between a wireless communication unit and an antenna arrangement;

wherein the integrated circuit is characterized by;

a processing module configured to;

process a coupled amount of at least one first signal from a first path operably coupleable to a first polarization of the antenna arrangement to determine at least one pilot signal from said at least one first signal;

process a coupled amount of at least one second signal from a second path operably coupleable to at least one second polarization feed of antenna arrangement, different to the first polarization, to determine the at least one pilot signal from said at least one second signal; and

determine a first phase relationship of the same pilot signal between the at least two RF paths.

23. A method for calibrating a phase relationship between two signal paths by a MIMO calibration device that is operably coupleable via at least two radio frequency (RF) paths between a wireless communication unit and an antenna arrangement, the method comprising:

processing a coupled amount of at least one first signal from a first path operably coupleable to a first polarization of the antenna arrangement to determine at least one pilot signal from said at least one first signal;

processing a coupled amount of at least one second signal from a second path operably coupleable to at least one second polarization feed of antenna arrangement, different to the first polarization, to determine the at least one pilot signal from said at least one second signal; and

determining a first phase relationship of the same pilot signal between the at least two RF paths.

24. A tangible computer program product comprising executable program code stored therein for execution on at least one processor for calibrating a phase relationship between two signal paths, the executable program code operable for performing the method of claim 23.