Detection of LTE ENB and UE emitters using signal processing algorithms for feature recognition
Characteristics of the waveform for received signals are determined. Statistical and/or Cyclostationary Signal Processing algorithms are used on the characteristics to identify each signal as a communication signal having a particular protocol. Autocorrelation, spectral correlation, and power Cepstrum, among others, are used to identify the signal using periodic characteristics of the waveform in the frequency domain. Rogue devices that do not adhere to the protocol are identified and actions taken accordingly.
1 . An apparatus for signal detection, the apparatus comprising:
a processor configured to:
receive an over-the-air signal from a communication device;
determine waveform characteristics of the over-the-air signal, the waveform characteristics including periodic characteristics;
determine movement of the apparatus using wavelet analysis;
determine, based on the waveform characteristics, whether the over-the-air signal is a communication signal having a predetermined standard protocol;
in response to a determination that the over-the-air signal is the communication signal having the predetermined standard protocol, identify the communication signal based on the periodic characteristics of the over-the-air signal and based on the movement of the apparatus as determined by the wavelet analysis; and
respond to the communication signal after identification; and
a memory configured to store the waveform characteristics.
2 . The apparatus of claim 1 , wherein the processor is configured to identify the over-the-air signal based on location of reference symbols of the over-the-air signal, a sampling frequency rate, and power level to translate the reference symbols into a frequency domain.
3 . The apparatus of claim 1 , wherein in response to a determination that the over-the-air signal is not the communication signal having the predetermined standard protocol, the processor is further configured to determine that the communication device is a rogue device that does not conform to the predetermined standard protocol and respond to the rogue device as indicated by instructions in the memory.
4 . The apparatus of claim 1 , wherein the processor is configured to identify the over-the-air signal as a specific communication signal based on Statistical and Cyclostationary Signal Processing algorithms used in a frequency domain.
5 . The apparatus of claim 1 , wherein the processor is configured to determine frequency and time locations of the over-the-air signal and identify the over-the-air signal as a specific communication signal based on the frequency and time locations of the waveform characteristics.
6 . The apparatus of claim 1 , wherein the processor is configured to determine peaks of autocorrelation of the over-the-air signal and identify the over-the-air signal as a specific communication signal based on the peaks of the autocorrelation.
7 . The apparatus of claim 1 , wherein the processor is configured to determine cyclostationary peaks of the over-the-air signal and identify the over-the-air signal as a specific communication signal based on the cyclostationary peaks.
8 . The apparatus of claim 1 , wherein the processor is configured to determine dips in a power Cepstrum of the over-the-air signal and identify the over-the-air signal as a specific communication signal based on the dips in the power Cepstrum.
9 . The apparatus of claim 1 , wherein the processor is configured to determine a spectrogram pattern of the over-the-air signal and identify the over-the-air signal as a specific communication signal based on the spectrogram pattern.
10 . The apparatus of claim 1 , wherein the processor is configured to determine a spectral correlation pattern of the over-the-air signal and identify the over-the-air signal as a specific communication signal based on the spectral correlation pattern.
11 . The apparatus of claim 1 , wherein the processor is configured to determine movement of the apparatus using wavelet analysis by generating a histogram of wavelet coefficients across multiple frequency bands and concatenating the histograms to form a motion vector.
12 . The apparatus of claim 11 , wherein the processor is configured to scale the wavelet coefficients by a constant with decreasing frequency during the wavelet analysis.
13 . The apparatus of claim 11 , wherein the processor is configured to distinguish between stationary and non-stationary states of the apparatus based on a distribution of the wavelet coefficients.
14 . The apparatus of claim 1 , wherein the processor is configured to use a motion vector derived from the wavelet analysis to adjust a threshold for identifying the communication signal.
15 . The apparatus of claim 1 , wherein the processor is configured to concatenate histograms of wavelet coefficients in different spatial directions to build a multi-dimensional motion vector for signal identification.
16 . A non-transitory computer-readable storage medium comprising instructions that, when executed by a processor, configure the processor to:
receive an over-the-air signal from a communication device;
determine waveform characteristics of the over-the-air signal, the waveform characteristics including periodic characteristics;
determine movement of the communication device using wavelet analysis;
determine, based on the waveform characteristics, whether the over-the-air signal is a communication signal having a predetermined standard protocol;
in response to a determination that the over-the-air signal is the communication signal having the predetermined standard protocol, identify the communication signal based on the periodic characteristics of the over-the-air signal and based on the movement of the apparatus as determined by the wavelet analysis; and
respond to the communication signal after identification.
17 . The non-transitory computer-readable storage medium of claim 16 , wherein the instructions, when executed by the processor, configure the processor to identify the over-the-air signal based on location of reference symbols of the over-the-air signal and a sampling frequency rate to translate the reference symbols into a frequency domain.
18 . The non-transitory computer-readable storage medium of claim 16 , wherein the instructions, when executed by the processor, further configure the processor to, in response to a determination that the over-the-air signal is not the communication signal having the predetermined standard protocol, determine that the communication device is a rogue device that does not conform to the predetermined standard protocol and respond to the rogue device as indicated by the instructions.
19 . A method comprising:
receiving an over-the-air signal from a communication device;
determining waveform characteristics of the over-the-air signal, the waveform characteristics including periodic characteristics;
determining movement of the communication device using wavelet analysis;
determining, based on the waveform characteristics, whether the over-the-air signal is a communication signal having a predetermined standard protocol;
in response to a determination that the over-the-air signal is the communication signal having the predetermined standard protocol, identifying the communication signal based on the periodic characteristics of the over-the-air signal and based on the movement of the apparatus as determined by the wavelet analysis; and
responding to the communication signal after identification.
20 . The method of claim 19 , wherein the periodic characteristics comprise location of reference symbols of the over-the-air signal and a sampling frequency rate to translate the reference symbols into a frequency domain.