ULTRA WIDE BAND WIRELESS RADIO TRANSMISSION IN MRI SYSTEMS INVOLVING CHANNEL ESTIMATION

• US 20090140739A1
• Filed: 05/09/2007
• Published: 06/04/2009
• Est. Priority Date: 05/25/2006
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Bennett, Jeffie K.
• Granted Patent: US 8,093,900 B2
• Time in Patent Office: Days
• US Class Current: 324/318
• CPC Class Codes: G01R 33/283 Intercom or optical viewing arrangements, structurally associated with NMR apparatus
• CPC Class Codes: G01R 33/3692 involving signal transmission without using electrically conductive connections, e.g. wireless communication or optical communication of the MR signal or an auxiliary signal other than the MR signal

Abstract

At least one radio frequency coil (28, 30) is disposed within an examination region (14), the radio frequency coil (28, 30) wirelessly receives a spread spectrum calibration signal from and transmits multiple channels of data in spread spectrum data signals to an associated wireless transceiver (60, 64; 62, 66). A channel estimator (104, 106) estimates frequency dependent signal strength characteristics based on the calibration signal between the wireless transceiver (60, 64; 62, 66) and the associated coil (28, 30). A signal strength adjuster (108, 110) makes a frequency dependent adjustment to the data signals strengths such that the transmitted data signals are compensated based on the estimated signal characteristics from the received calibration signal to create frequency dependent compensated data signals.

Claims

1. A magnetic resonance system comprising:

at least one radio frequency coil disposed within an examination region, the radio frequency coil wirelessly receives a spread spectrum calibration signal from and transmits multiple channels of data in spread spectrum data signals to an associated wireless transceiver, the radio frequency coil including;

a channel estimator which estimates frequency dependent signal strength characteristics based on the calibration signal between the wireless transceiver and the associated coil, and

a signal strength adjuster which makes a frequency dependent adjustment to the data signals strengths such that the transmitted data signals are compensated based on the estimated signal characteristics from the received calibration signal to create frequency dependent compensated data signals.

2. The system as set forth in claim 1, wherein the channel estimator is programmed to:

compare the strengths of the received signals at each of a plurality of frequencies of the spread spectrum calibration signal with a predetermined signal strength; and

based on the comparison, determine frequencies with stronger and weaker signal reception.

3. The system as set forth in claim 2, wherein the signal strength adjuster is programmed to:

reduce strengths of the data signals determined to be stronger.

4. The system as set forth in claim 3, wherein the radio frequency coil further includes:

a transmitter which transmits the compensated data signals to the wireless transceivers.

5. The system as set forth in claim 1, further including:

a plurality of the wireless transceivers disposed at at least first and second communication points around the examination region.

6. The system as set forth in claim 5, further including:

at least two of the radio frequency coils both disposed in the examination region concurrently; and

at least two of the transceivers located at each of the communication points such that a first of the transceivers at each communication point wirelessly transmits the calibration signal to and receives the compensated signal data from a first coil and a second of the transceivers at each communication point wirelessly transmits the calibration signal to and receives the compensated data signal from a second coil.

7. The system as set forth in claim 5, wherein each transceiver includes:

associated first and second companion antennas for diversity reception/transmission.

8. The system as set forth in claim 1, wherein the calibration signal and the data signal are ultra wide band (UWB) signals.

9. The system as set forth in claim 1, further including:

a preamble device which adjusts a size of a preamble of a transmitted data packet based on the estimated signal characteristics.

10. The system as set forth in claim 9, wherein the preamble size is one of 6 and 12 symbols.

11. A magnetic resonance imaging method comprising:

wirelessly receiving a spread spectrum calibration signal between a radio frequency coil and an associated wireless transceiver;

estimating frequency dependent signal strength characteristics based on the calibration signal between the wireless transceiver and the coil;

based on the estimate, making frequency dependent signal strengths adjustments to spread spectrum data signals which carry data acquired in an examination region to create frequency dependent compensated data signals, and

transmitting the compensated data signals to the associated wireless transceiver.

12. The method as set forth in claim 11, wherein the step of estimating includes:

comparing the strengths of the received calibration signal at each of a plurality of frequencies with a selected signal strength;

based on the comparison, determining frequencies with stronger and weaker signal reception; and

reducing strengths of the frequencies of the data signals determined to be stronger.

13. The method as set forth in claim 12, wherein the step of transmitting includes:

transmitting the compensated signals to the wireless transceivers absent selective frequency fading effects.

14. The method as set forth in claim 11, wherein the calibration signals and the data signals are ultra wide band (UWB) signals.

15. The method as set forth in claim 14, further including:

associating first and second transceivers with each of a plurality of communication points around the imaging region;

disposing at least a first and a second of the radio frequency coils in the examination region;

wirelessly transmitting the calibration signal from at least one first transceiver to the first coil;

wirelessly transmitting the calibration signal from at least one second transceiver to the second coil;

wirelessly receiving the compensated data signal from the first coil by at least one first transceiver; and

wirelessly receiving the compensated data signal from the second coil by at least one second transceiver.

16. The method as set forth in claim 15, wherein each transceiver includes associated first and second companion antennas and further including:

selecting among the antennas for diversity reception/transmission.

17. The method as set forth in claim 11, further including:

periodically retransmitting the calibration signals and re-estimating the frequency dependent signal strength characteristics.

18. The method as set forth in claim 11, further including:

prior to the step of transmitting, adjusting a preamble size of each transmitted data packet;

transmitting the compensated data with adjusted preambles to the associated wireless transceiver; and

synchronizing a receiver of the wireless transceiver with the adjusted preamble.

19. A magnetic resonance system comprising:

at least one frequency coil disposed within an examination region, the coil wirelessly receives a spread spectrum calibration signal and transmits spread spectrum data signals to an associated wireless transceiver, the coil including;

a channel estimator which estimates signal characteristics based on the calibration signal transmitted between the wireless transceiver and an associated coil, and

a preamble device which adjusts a size of a preamble of each transmitted data packet based on the estimated characteristics of the signals.

20. The system as set forth in claim 19, further including:

a signal strength adjuster which adjusts signals strengths of the transmitted spread spectrum data such that the transmitted data signals are compensated based on the estimated signal characteristics from the received data calibration signal.