DEVICE AND METHOD FOR CALIBRATING MIMO SYSTEMS

• US 20080285637A1
• Filed: 05/28/2008
• Published: 11/20/2008
• Est. Priority Date: 11/29/2005
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Interuniversitair Micro-Electronica Centrum VZW (IMEC International), Samsung Electronics Co. Ltd.
• Inventors: Liu, Jian, Vandersteen, Gerd
• Granted Patent: US 8,126,040 B2
• Time in Patent Office: Days
• US Class Current: 375/224
• CPC Class Codes: H01Q 3/267 Phased-array testing or checking devices
• CPC Class Codes: H04B 17/20 of receivers

Abstract

A device and method for calibrating MIMO systems are disclosed. In one aspect, a calibration circuit comprises at least a first and a second input/output port, each arranged for being connected to a different transmitter/receiver pair of a multiple input multiple output (MIMO) system. The circuit further comprises at least a third and a fourth input/output port, each arranged for being connected to a different antenna. The circuit further comprises an attenuator having a first attenuator port and a second attenuator port. The circuit further comprises a first and a second non-reciprocal switch, the first switch being arranged for establishing a connection between the first input/output port and either the third input/output port or the first attenuator port, and the second switch arranged for establishing a connection between the second input/output port and either the fourth input/output port or the second attenuator port.

Claims

1. A calibration circuit comprising:

at least a first and a second input/output port, each arranged for being connected to a different transmitter/receiver pair of a multiple input multiple output (MIMO) system;

at least a third and a fourth input/output port, each arranged for being connected to a different antenna;

an attenuator having a first attenuator port and a second attenuator port;

a first and a second non-reciprocal switch, the first switch being arranged for establishing a connection between the first input/output port and either the third input/output port or the first attenuator port, and the second switch arranged for establishing a connection between the second input/output port and either the fourth input/output port or the second attenuator port.

2. The circuit of claim 1, wherein the transfer function of the connection of the first switch to the first attenuator port and via the second attenuator port to the second switch is substantially equal to the transfer function of the connection of the second switch to the second attenuator port and via the first attenuator port to the first switch.

3. A system comprising a calibration circuit of claim 1, further comprising at least two transmitter/receiver pairs of the MIMO system.

4. A method of determining a measure of the relative analogue front end mismatch of at least a first and second transmit/receive pairs of a multiple input multiple output (MIMO) system, the method comprising:

selecting a first transmitter/receiver pair of a MIMO system as a reference;

transmitting a known test signal from the reference transmitter to the receiver of the second transmitter/receiver pair and determining a corresponding first transfer function;

transmitting the known test signal from the transmitter of the second transmitter/receiver pair to the reference receiver and determining a corresponding second transfer function; and

determining from the first and second transfer function the measure of relative mismatch.

5. The method of claim 4, further comprising multiplying a signal to be fed to the transmitter of the second transmitter/receiver pair with the determined measure of relative mismatch.

6. The method of claim 4, wherein the method is applied to each individual subcarrier of a multicarrier system.

7. The method of claim 4, wherein the known test signal is a BPSK IEEE 802.11a long training symbol.

8. A device for determining a measure of the relative analogue front end mismatch of at least a first and second transmit/receive pairs of a multiple input multiple output (MIMO) system, the device comprising:

means for selecting a first transmitter/receiver pair of a MIMO system as a reference;

means for transmitting a known test signal from the reference transmitter to the receiver of the second transmitter/receiver pair and determining a corresponding first transfer function;

means for transmitting the known test signal from the transmitter of the second transmitter/receiver pair to the reference receiver and determining a corresponding second transfer function; and

means for determining from the first and second transfer function the measure of relative mismatch.