Method, apparatus, analyser and computer program of searching for propagation paths

1. A method of searching for propagation paths in a digital impulse response estimate of a channel relating to a radio system in order to use the paths in a radio channel estimation, the paths corresponding to the highest amplitude values in the digital impulse response estimate of the channel, the method comprising:

dividing, by a processing device, the impulse response estimate temporally into at least two subsignals that occupy different predetermined periods of time;

determining, by the processing device, whether a distribution of the amplitude values of at least one subsignal is gaussian or non-gaussian using a degree of symmetry associated with the distribution of the amplitude values; and

searching, by the processing device, for at least a highest amplitude value in each sub-signal, which is determined to be non-gaussian, to form a radio channel to be used in the radio channel estimation, the radio channel including each propagation path that corresponds to the highest amplitude value in each subsignal determined to be non-gaussian.

2. A method of forming a radio channel for a radio channel simulation, the radio channel including propagation paths from a digital impulse response estimate of a channel relating to a CDMA radio system, the paths corresponding to the highest amplitude values in the digital impulse response estimate of the channel, the method comprising:

dividing, by a processing device, the impulse response estimate temporally into at least two subsignals that occupy different predetermined periods of time;

determining, by the processing device, whether a distribution of the amplitude values of at least one subsignal is gaussian or non-gaussian using a degree of symmetry associated with the distribution of the amplitude values;

searching, by the processing device, for a highest amplitude value in each subsignal, which is determined to be non-gaussian; and

forming, by the processing device, a radio channel including each propagation path that corresponds to the highest amplitude value in each subsignal, which is determined to be non-gaussian, for a radio channel simulation.

3. The method of claim 1 , further comprising:

measuring a degree of gaussianity of the distribution of the amplitude values of at least one subsignal; and

determining the distribution to be non-gaussian, if the degree of gaussianity is below a predetermined threshold.

4. The method of claim 1 , further comprising:

forming a median of the amplitude values of at least one subsignal;

forming a mean of the amplitude values of at least one subsignal; and

determining the distribution to be non-gaussian, if the median and the mean differ from each other more than a reference difference.

5. The method of claim 1 , further comprising:

forming a mode of the amplitude values of at least one subsignal;

forming a mean of the amplitude values of at least one subsignal; and

determining the distribution to be non-gaussian, if the mode and the mean differ from each other more than a reference difference.

6. The method of claim 1 , further comprising:

forming a mode of the amplitude values of at least one subsignal;

forming a median of the amplitude values of at least one subsignal; and

determining the distribution to be non-gaussian, if the mode and the median differ from each other more than a reference difference.

7. The method of claim 1 , further comprising searching additionally for at least one amplitude value which has a lower value than the highest amplitude value in each subsignal determined to be non-gaussian.

8. An apparatus for searching for propagation paths in a digital impulse response estimate of a channel relating to a radio system in order to use the paths in a radio channel estimation, the paths corresponding to the highest amplitude values in the digital impulse response estimate of the channel, the apparatus comprising:

a divider configured to divide the impulse response estimate temporally into at least two subsignals that occupy different predetermined periods of time;

an analyser configured to determine whether a distribution of the amplitude values of at least one subsignal is gaussian or non-gaussian using a degree of symmetry associated with the distribution of the amplitude values; and

a searcher configured to search for a highest amplitude value in each subsignal, which is determined to be non-gaussian, to form a radio channel to be used in the radio channel estimation, the radio channel including each propagation path that corresponds to the highest amplitude value in each subsignal determined to be non-gaussian.

9. An apparatus for forming a radio channel for a radio channel simulation, the radio channel including propagation paths from a digital impulse response estimate of a channel relating to a CDMA radio system, the paths corresponding to the highest amplitude values in the digital impulse response estimate of the channel, the apparatus comprising:

a divider configured to divide the impulse response estimate temporally into at least two subsignals that occupy different predetermined periods of time;

an analyser configured to determine whether a distribution of the amplitude values of at least one subsignal is gaussian or non-gaussian using a degree of symmetry associated with the distribution of the amplitude values;

a searcher configured to search for a highest amplitude value in each subsignal, which is determined to be non-gaussian; and

a generator configured to form a radio channel for a radio channel simulation, the radio channel including each propagation path that corresponds to the highest amplitude value in each subsignal determined to be non-gaussian.

10. The apparatus of claim 8 , wherein the analyser is configured to

measure a degree of gaussianity of the distribution of the amplitude values of at least one subsignal; and

determine the distribution to be non-gaussian, if the degree of symmetry is below a predetermined threshold.

11. The apparatus of claim 8 , wherein the analyser is configured to

form a median of the amplitude values of at least one subsignal;

form a mean of the amplitude values of at least one subsignal; and

determine the distribution to be non-gaussian, if the median and the mean differ from each other more than a reference difference.

12. The apparatus of claim 8 , wherein the analyser is configured to

form a mode of the amplitude values of at least one subsignal;

form a mean of the amplitude values of at least one subsignal; and

determine the distribution to be non-gaussian, if the mode and the mean differ from each other more than a reference difference.

13. The apparatus of claim 8 , wherein the searcher is configured to additionally search for at least one amplitude value which has a lower value than the highest value in each subsignal determined to be non-gaussian.

14. An apparatus for searching for propagation paths in a digital impulse response estimate of a channel relating to a radio system in order to use the paths in a radio channel estimation, the paths corresponding to the highest amplitude values in the digital impulse response estimate of the channel, the apparatus comprising:

means for dividing the impulse response estimate temporally into at least two subsignals that occupy different predetermined periods of time;

means for determining whether a distribution of the amplitude values of at least one subsignal is gaussian or non-gaussian using a degree of symmetry associated with the distribution of the amplitude values; and

means for searching for a highest amplitude value in each subsignal, which is determined to be non-gaussian, to form a radio channel to be used in the radio channel estimation, the radio channel including each propagation path that corresponds to the highest amplitude value in each subsignal determined to be non-gaussian.

15. An apparatus for forming a radio channel for a radio channel simulation, the radio channel including propagation paths from a digital impulse response estimate of a channel relating to a radio system, the paths corresponding to the highest amplitude values in the digital impulse response estimate of the channel, the apparatus comprising:

means for dividing the impulse response estimate temporally into at least two subsignals that occupy different predetermined periods of time;

means for determining whether a distribution of the amplitude values of at least one subsignal is gaussian or non-gaussian using a degree of symmetry associated with the distribution of the amplitude values;

means for searching for a highest amplitude value in each subsignal, which is determined to be non-gaussian; and

means for forming a radio channel for a radio channel simulation, the radio channel including each propagation path that corresponds to the highest amplitude value in each subsignal determined to be non-gaussian.

16. An analyser for determining a degree of symmetry of a distribution of amplitude values of an impulse response estimate of a channel relating to a radio system, wherein the analyser is configured to

receive at least one subsignal which is a temporally divided section of the impulse response estimate that occupy different predetermined periods of time; and

determine a degree of gaussianity of the distribution of the amplitude values of at least one subsignal using a degree of symmetry associated with the distribution of the amplitude values.

17. A computer program product stored in a non-transitory computer-readable medium, the computer program product including a computer program of instructions that, when executed by a processing device, perform a computer process that searches for propagation paths in a digital impulse response estimate of a channel relating to a radio system in order to use the paths in a radio channel estimation, the paths corresponding to the highest amplitude values in the digital impulse response estimate of the channel, the computer process comprising:

dividing the impulse response estimate temporally into at least two subsignals that occupy different predetermined periods of time;

determining whether a distribution of the amplitude values of at least one subsignal is gaussian or non-gaussian using a degree of symmetry associated with the distribution of the amplitude values;

searching for a highest amplitude value in each subsignal, which is determined to be non-gaussian, to form a radio channel to be used in the radio channel estimation, the radio channel including each propagation path that corresponds to the highest amplitude value in each subsignal determined to be non-gaussian.

18. A computer program product stored in a non-transitory computer-readable medium, the computer program product including a computer program of instructions that, when executed by a processing device, perform a computer process that searches for propagation paths in a digital impulse response estimate of a channel relating to a radio system in order to use the paths in a radio channel estimation, the paths corresponding to the highest amplitude values in the digital impulse response estimate of the channel, the process comprising:

dividing the impulse response estimate temporally into at least two subsignals that occupy different predetermined periods of time;

determining whether a distribution of the amplitude values of at least one subsignal is gaussian or non-gaussian using a degree of symmetry associated with the distribution of the amplitude values;

searching for a highest amplitude value in each subsignal, which is determined to be non-gaussian; and

forming a radio channel including each propagation path that corresponds to the highest amplitude value in each subsignal, which is determined to be non-gaussian, for the radio channel estimation.

19. A non-transitory computer program distribution medium readable by a computer, the non-transitory computer program distribution medium including a computer program of instructions for executing a computer process for searching for propagation paths in a digital impulse response estimate of a channel relating to a radio system in order to use the paths in a radio channel estimation, the paths corresponding to the highest amplitude values in a digital impulse response estimate of a channel, the computer process comprising:

dividing the impulse response estimate temporally into at least two subsignals that occupy different predetermined periods of time;

determining whether a distribution of the amplitude values of at least one subsignal is gaussian or non-gaussian using a degree of symmetry associated with the distribution of the amplitude values; and

searching for a highest amplitude value in each subsignal, which is determined to be non-gaussian, to form a radio channel to be used in the radio channel estimation, the radio channel including each propagation path that corresponds to the highest amplitude value in each subsignal determined to be non-gaussian.

20. A non-transitory computer program distribution medium readable by a computer, the non-transitory computer program distribution medium including a computer program of instructions for executing a computer process for searching for propagation paths in a digital impulse response estimate of a channel relating to a radio system in order to use the paths in a radio channel estimation, the paths corresponding to the highest amplitude values in a digital impulse response estimate of a channel, the computer process comprising:

dividing the impulse response estimate temporally into at least two subsignals that occupy different predetermined periods of time;

determining whether a distribution of the amplitude values of at least one subsignal is gaussian or non-gaussian using a degree of symmetry associated with the distribution of the amplitude values;

searching for a highest amplitude value in each sub signal, which is determined to be non-gaussian; and

forming a radio channel including each propagation path that corresponds to the highest amplitude value in each subsignal, which is determined to be non-gaussian, for the radio channel estimation.

21. The non-transitory computer program distribution medium of claim 19 , wherein the distribution medium comprises a computer readable medium, a program storage medium, a record medium, a computer readable memory, a computer readable software distribution package, or a computer readable compressed software package.

22. The method of claim 2 , further comprising:

measuring a degree of gaussianity of the distribution of the amplitude values of at least one subsignal; and

determining the distribution to be non-gaussian, if the degree of gaussianity is below a predetermined threshold.

23. The method of claim 2 , further comprising:

forming a median of the amplitude values of at least one subsignal;

forming a mean of the amplitude values of at least one subsignal; and

determining the distribution to be non-gaussian, if the median and the mean differ from each other more than a reference difference.

24. The method of claim 2 , further comprising:

forming a mode of the amplitude values of at least one subsignal;

forming a mean of the amplitude values of at least one subsignal; and

determining the distribution to be non-gaussian, if the mode and the mean differ from each other more than a reference difference.

25. The method of claim 2 , further comprising:

forming a mode of the amplitude values of at least one subsignal;

forming a median of the amplitude values of at least one subsignal; and

determining the distribution to be non-gaussian, if the mode and the median differ from each other more than a reference difference.

26. The method of claim 2 , further comprising searching additionally for at least one amplitude value which has a lower value than the highest amplitude value in each subsignal determined to be non-gaussian.

27. The apparatus of claim 9 , wherein the analyser is configured to

measure a degree of gaussianity of the distribution of the amplitude values of at least one subsignal; and

determine the distribution to be non-gaussian, if the degree of symmetry is below a predetermined threshold.

28. The apparatus of claim 9 , wherein the analyser is configured to

form a median of the amplitude values of at least one subsignal;

form a mean of the amplitude values of at least one subsignal; and

determine the distribution to be non-gaussian, if the median and the mean differ from each other more than a reference difference.

29. The apparatus of claim 9 , wherein the analyser is configured to

form a mode of the amplitude values of at least one subsignal;

form a mean of the amplitude values of at least one subsignal; and

determine the distribution to be non-gaussian, if the mode and the mean differ from each other more than a reference difference.

30. The apparatus of claim 9 , wherein the searcher is configured to additionally search for at least one amplitude value which has a lower value than the highest value in each subsignal determined to be non-gaussian.

31. The non-transitory computer program distribution medium of claim 20 , wherein the distribution medium comprises a computer readable medium, a program storage medium, a record medium, a computer readable memory, a computer readable software distribution package, or a computer readable compressed software package.