Apparatus and method for communication

1. An apparatus comprising at least one processor configured to cause the apparatus:

obtain as an input a sampled signal;

determine an 8 th order moment for a group of samples of the input signal corresponding to a length of one or two frames of a Global System for Mobile communication (GSM) signal;

determine peak to average power and peak to average power variance for the group of samples of the input signal corresponding to the length of one or two frames of a GSM signal;

compare the obtained 8 th order moment to predetermined thresholds and the obtained peak to average power and peak to average power variance to predetermined thresholds;

determine whether the input signal is a GSM-type signal on the basis of the comparisons.

2. The apparatus of claim 1 , at least one processor further configured to cause the apparatus

determine inverse magnitude of signal energy over a number of samples, the number of samples corresponding to a given number of GSM slots;

determine a peak value in the inverse magnitude of signal energy;

determine signal energy using a sample window centered over a peak value;

determine average energy outside the sample window;

calculate signal to noise ratio on the basis of the determined signal energy and average energy;

determine whether the input signal is a GSM-type signal on the basis of the comparisons.

3. The apparatus of claim 1 , the apparatus being configured to

determine received signal strength indicator for the group of samples of the input signal corresponding to the length of one or two frames of a GSM signal prior determining the 8 th order moment for the group of samples.

4. The apparatus of claim 3 , the apparatus being configured to compare the determined received signal strength indicator to a given threshold

determine whether the input signal is a GSM-type signal on the basis of the comparison, and output the determined received signal strength indicator and start analysing next group of samples.

5. An apparatus, comprising:

means for obtaining as an input a sampled signal;

means for determining an 8 th order moment for a group of samples of the input signal corresponding to a length of one or two frames of a Global System for Mobile communication (GSM) signal;

means for determining peak to average power and peak to average power variance for the group of samples of the input signal corresponding to the length of one or two frames of a GSM signal;

means for comparing the obtained 8 th order moment to predetermined thresholds and the obtained peak to average power and peak to average power variance to predetermined thresholds;

means for determining whether the input signal is a GSM-type signal on the basis of the comparisons.

6. A method for recognizing Global System for Mobile communication (GSM) signals, the method comprising:

obtaining as an input a sampled signal;

determining an 8 th order moment for a group of samples of the input signal corresponding to a length of one or two frames of a GSM signal;

determining peak to average power and peak to average power variance for the group of samples of the input signal corresponding to the length of one or two frames of a GSM signal;

comparing the obtained 8 th order moment to predetermined thresholds and the obtained peak to average power and peak to average power variance to predetermined thresholds;

determining whether the input signal is a GSM-type signal on the basis of the comparisons.

7. The method of claim 6 , further comprising:

determining inverse magnitude of signal energy over a number of samples, the number of samples corresponding to a given number of GSM slots;

determining a peak value in the inverse magnitude of signal energy;

determining signal energy using a sample window centered over a peak value;

determining average energy outside the sample window;

calculating signal to noise ratio on the basis of the determined signal energy and average energy;

determining whether the input signal is a GSM-type signal on the basis of the comparisons.

8. The method of claim 6 , further comprising:

determining received signal strength indicator for the group of samples of the input signal corresponding to the length of one or two frames of a GSM signal prior determining the 8 th order moment for the group of samples.

9. The method of claim 8 , further comprising:

comparing the determined received signal strength indicator to a given threshold

determining whether the input signal is a GSM-type signal on the basis of the comparison, and output the determined received signal strength indicator and start analysing next group of samples.

10. A computer program product embodied on a non-transitory distribution medium readable by a computer and comprising program instructions which, when loaded into an apparatus, execute a computer process comprising:

obtaining as an input a sampled signal;

determining an 8 th order moment for a group of samples of the input signal corresponding to a length of one or two frames of a GSM signal;

determining peak to average power and peak to average power variance for the group of samples of the input signal corresponding to the length of one or two frames of a GSM signal;

comparing the obtained 8 th order moment to predetermined thresholds and the obtained peak to average power and peak to average power variance to predetermined thresholds;

determining whether the input signal is a GSM-type signal on the basis of the comparisons.