CALIBRATION TECHNIQUES FOR MIMO WIRELESS COMMUNICATION SYSTEMS

• US 20090323783A1
• Filed: 06/25/2008
• Published: 12/31/2009
• Est. Priority Date: 06/25/2008
• Status: Abandoned Application

• Current Assignee: Motorola Mobility LLC (Lenovo Group Ltd.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Vook, Frederick W., Mueller, Bruce D., Buris, Nicholas E.
• Application Number:
  US12/145,756
• Publication Number:
  US 20090323783A1
• Time in Patent Office: Days
• US Class Current: 375/219
• CPC Class Codes: H01Q 1/523 between antennas of an array
• CPC Class Codes: H01Q 3/267 Phased-array testing or checking devices
• CPC Class Codes: H04B 17/21 for calibration; for correcting measurements
• CPC Class Codes: H04B 7/0413 MIMO systems

Abstract

A method, apparatus and system for performing over-the-air calibration routines in a multiple-input multiple-output (MIMO) communication system. An antenna array of a transceiver (e.g., transceiver of a base station) comprises a re-configurable antenna having two switchable configuration states. The antenna exhibits different degrees of electromagnetic coupling to other antennas of the array in a first state than in a second state. The reference antenna is switched to the first state for performing uplink/downlink calibrating transmissions and switched to the second state during uplink and downlink communications or channel sounding calibrating transmissions.

Claims

1. A wireless communication apparatus, comprising:

a transceiver; and

an antenna array operated by the transceiver, wherein one antenna of the array is controllably switchable between;

(i) a first state, in which the antenna exhibits a first value of electromagnetic coupling to other antennas of the array; and

(ii) a second state, in which the antenna exhibits a second value of the electromagnetic coupling to the other antennas of the array.

2. The apparatus of claim 1, wherein the antenna is a re-configurable antenna.

3. The apparatus of claim 2, wherein the antenna comprises components configured for switching the antenna between the first and second states.

4. The apparatus of claim 3, wherein the components include active electronic devices or micro-electromechanical systems (MEMS).

5. The apparatus of claim 1, wherein said apparatus is configured to perform uplink and downlink communications and calibration routines using a multiple-input multiple-output (MIMO) techniques.

6. The apparatus of claim 5, wherein the calibration routines include uplink/downlink calibrating transmissions between the antenna and the other antennas of the array.

7. The apparatus of claim 6, wherein the antenna is switched to the first state during the uplink/downlink calibrating transmissions.

8. The apparatus of claim 6, wherein the antenna is switched to the second state during one of (i) the uplink and downlink communications and (ii) the channel sounding transmissions.

9. The apparatus of claim 1, wherein the apparatus is a base or access station of a wireless communication system.

10. A wireless communication system, comprising:

one or more base stations or access stations; and

one or more user terminals, each of said stations and terminals having a transceiver and an antenna array operated by the transceiver, wherein one antenna of the array is controllably switchable between;

(i) a first state, in which the antenna exhibits a first value of electromagnetic coupling to other antennas of the array; and

(ii) a second state, in which the antenna exhibits a second value of the electromagnetic coupling to the other antennas of the array.

11. The system of claim 10, wherein the antenna is a re-configurable antenna.

12. The system of claim 11, wherein the antenna comprises components configured for switching the antenna between the first and second states.

13. The system of claim 12, wherein the components include active electronic devices or micro-electromechanical systems (MEMS).

14. The system of claim 10, wherein said system is configured to perform uplink and downlink communications and calibration routines using a multiple-input multiple-output (MIMO) techniques.

15. The system of claim 14, wherein the calibration routines include (i) uplink/downlink calibrating transmissions between the antenna and the other antennas of the array and (ii) channel sounding transmissions.

16. The system of claim 15, wherein the antenna is switched to the first state during the uplink/downlink calibrating transmissions.

17. The system of claim 15, wherein the antenna is switched to the second state during one of (i) the uplink and downlink communications and (ii) the channel sounding transmissions.

18. A method of operating a multiple-input multiple-output (MIMO) wireless communication system, comprising:

providing base or access stations and user terminals with antenna arrays, each antenna array having an antenna controllably switchable between;

(i) a first state, in which the antenna exhibits a first value of electromagnetic coupling to other antennas of the array; and

(ii) a second state, in which the antenna exhibits a second value of the electromagnetic coupling to the other antennas of the array;

switching the antenna to the first state during uplink/downlink calibrating transmissions between the antenna and the other antennas of the array; and

switching the antenna to the second state during one of (a) uplink and downlink communications and (b) channel sounding transmissions.

19. The method of claim 18, further comprising:

providing the antenna with components configured for switching the antenna between the first and second states, the components including active electronic devices or micro-electromechanical systems (MEMS).

20. The method of claim 18, further comprising:

determining forward and reverse gains of branches of a transceiver using the uplink/downlink calibrating transmissions; and

determining downlink channel estimations using the channel sounding transmissions.