METHOD AND DEVICE IN A COMMUNICATION NETWORK

• US 20130165105A1
• Filed: 02/22/2013
• Published: 06/27/2013
• Est. Priority Date: 06/05/2009
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Mindspeed Technologies UK Limited (MACOM Technology Solutions Holdings, Inc.)
• Inventors: Whinnett, Nicholas William
• Granted Patent: US 8,862,076 B2
• Time in Patent Office: Days
• US Class Current: 455/422.1
• CPC Class Codes: H04B 17/26 using historical data, averaging values or statistics
• CPC Class Codes: H04B 17/309 Measuring or estimating channel quality parameters
• CPC Class Codes: H04W 24/02 Arrangements for optimising operational condition
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 52/244 Interferences in heterogeneous networks, e.g. among macro and femto or pico cells or other sector / system interference [OSI]
• CPC Class Codes: H04W 52/36 with a discrete range or set of values, e.g. step size, ramping or offsets
• CPC Class Codes: H04W 84/045 using private Base Stations, e.g. femto Base Stations, home Node B

Abstract

There is provided a method of method of estimating a quality of a signal, the method in a first device comprising measuring a signal transmitted from a second device to a third device; determining a value of a metric from an autocorrelation function of the measured signal; and determining an estimate of the quality of the signal from the determined metric.

Claims

1. A method of estimating a quality of a signal, the method in a first device comprising:

measuring a signal transmitted from a second device to a third device;

determining a value of a metric from an autocorrelation function of the measured signal; and

determining an estimate of the quality of the signal from the determined metric.

2. A method as claimed in claim 1 wherein the step of measuring comprises measuring the signal in the time domain, and the step of determining a value of a metric comprises determining the autocorrelation function of the time domain signal and noise.

3. A method as claimed in claim 1 wherein the step of determining a value of a metric comprises determining the autocorrelation function comprises:

normalising the measured signal to give a sequence r;

taking the fast Fourier transform of this sequence to give f;

determining the squared magnitude of each sample in f; and

taking the inverse fast Fourier transform of the sequence resulting from the step of determining the squared magnitude to give an autocorrelation sequence a.

4. A method as claimed in claim 1 wherein the step of determining a value of a metric from an autocorrelation function of the measured signal comprises calculating the magnitude or squared magnitude of the autocorrelation function.

5. A method as claimed in claim 4 wherein the step of determining a value of a metric further comprises adjusting or zeroing the central tap in the output of the step of calculating.

6. A method as claimed in claim 5 wherein the step of determining a value of a metric further comprises adjusting or zeroing the tap adjacent the central tap in the output of the step of calculating.

7. A method as claimed in claim 5 with the step of determining a value of a metric from an autocorrelation function of the measured signal comprising calculating the magnitude of the autocorrelation function, and the step of determining a value of a metric comprises:

identifying the tap with the largest magnitude in the taps remaining in the output of the step of calculating; and

setting the metric to the value of the magnitude of the identified tap.

8. A method as claimed in claim 5 with the step of determining a value of a metric from an autocorrelation function of the measured signal comprising calculating the squared magnitude of the autocorrelation function, and the step of determining a value of a metric comprises:

identifying the tap with the largest squared magnitude in the taps remaining in the output of the step of calculating; and

setting the metric to the value of the squared magnitude of the identified tap.

9. A method as claimed in claim 7 wherein the step of determining a value of a metric further comprises adjusting the value of the metric based on the distance of the identified tap from the central tap.

10. A method as claimed in claim 7 wherein the step of determining a value of a metric further comprises adjusting the value of the metric based on a function of a peak to average power ratio of the measured signal.

11. A method as claimed in claim 10 wherein the step of adjusting the value of the metric based on a function of a peak to average power ratio of the measured signal comprises in the event that the peak to average power ratio of the measured signal is below a threshold value, adjusting the value of the metric to a minimum value.

12. A method as claimed in claim 1 wherein the step of determining an estimate of the quality of the signal from the determined metric comprises comparing the determined metric to a look-up table.

13. A method as claimed in claim 1 wherein the step of determining an estimate of the quality of the signal from the determined metric comprises using a curve-fitting technique to match the determined metric to a predetermined relationship between values for the metric and the quality of the signal.

14. A method as claimed in claim 1 wherein the step of measuring comprises measuring a Zadoff-Chu reference signal transmitted from the second device to the third device.

15. A method as claimed in claim 14 wherein the step of measuring a Zadoff-Chu reference signal comprises estimating the position of the Zadoff-Chu reference signal in time.

16. A method as claimed in claim 14 wherein the step of measuring comprises measuring a portion of the Zadoff-Chu reference signal.

17. A method as claimed in claim 1 further comprising the step of using a scheduler to ensure that no signals will be transmitted to the first device from other devices associated therewith that might interfere with the execution of the step of measuring.

18. A method as claimed in claim 1 wherein the quality of the signal is a signal to noise ratio.

19. A method as claimed in claim 1 wherein the first device is a femtocell base station, the second device is a mobile device, and the third device is a macrocell base station or another femtocell base station, such that the mobile device is associated with the macrocell base station or said another femtocell base station.

20. A network element for use in a communication network, the network element comprising a first device configured to:

measure a signal transmitted from a second device to a third device;

determine a value of a metric from an autocorrelation function of the measured signal; and

determine an estimate of the quality of the signal from the determined metric.

21. A network element as claimed in claim 20 wherein the network element comprises a femtocell base station.