Method for detecting active radiofrequency wireless communication signal in a region

Patent metadata

Field	Value
Publication number	US-11082148-B2
Application number	US-201916285049-A
Country	US
Kind code	B2
Filing date	Feb 25, 2019
Priority date	Oct 26, 2018
Publication date	Aug 3, 2021
Grant date	Aug 3, 2021

Abstract

The use of mobile telephones have come into widespread use in such a way that day to day life has become very much dependent on them. This results in unintentional or intentional use of mobile phones in the prohibited areas such as examination centers. A method for detecting active radiofrequency wireless communication signal in a region has been provided. The method involves two stages, calibration stage and mobile phone detection stage. In the calibration stage, the frequency on which the mobile towers in that region are operating are identified. The identified frequency is then used to detect the active wireless RF communication using a plurality of software defined radios (SDR) and the existing client systems present in the region. The method further configured to determine the exact location of the mobile phone from the RF communication signal is generated.

First claim

What is claimed is:

1. A method for detecting active radiofrequency (RF) wireless communication in a region,
the method comprising processor one or more hardware processors implementing steps of:
identifying one or more mobile bands present in the region, wherein each of the one or more mobile bands are present in a plurality of mobile signals coming out of a mobile tower in the region;
dividing downlink frequencies of the one or more mobile bands among a plurality of frequency slots and further distributing among a plurality of client systems in time division domain, wherein the distributing is performed dynamically depending upon availability of the plurality of client systems by a central server;
detecting active channels out of the one or more mobile bands based on broadcast control channel information (BCCH) transmitted by the mobile tower in the region;
sending the BCCH information of the detected active channels back to the central server;
calculating respective uplink channel frequency corresponding to the detected active channel from the downlink frequencies;
redistributing the detected active channels among the plurality of client systems dynamically in the time division domain;
tuning a plurality of software defined radios (SDRs) associated with the plurality of client systems to the uplink channel frequencies;
capturing a raw signal generated from the SDRs in the form of binary data;
performing a cyclic-autocorrelation on the raw signal;
filtering a cyclic-autocorrelated signal resulting from performing the cyclic-autocorrelation on the raw signal to remove a plurality of noises;
enhancing and extracting a plurality of features from the filtered cyclic-autocorrelated signal;
providing the extracted plurality of features to a support vector machine classifier to classify the presence of an active RF signal;
extracting a target device signal information if the active RF signal is detected;
and sending the target device signal information to the central server.

2. The method of claim 1 , wherein the target device signal information and signal source position is calculated from the active RF signal using a triangulation method.

3. The method of claim 1 further comprising the step of determining bandwidth, uplink frequencies and operator information of the plurality of bands.

4. The method of claim 1 , wherein the plurality of features include peak position, standard deviation, slope calculation and ratio calculation.

5. The method of claim 4 , wherein the peak position is derived from the filtered cyclic-auto correlated signal and the standard deviation, the slope calculation and the ratio calculation, are derived from normal distribution of the filtered cyclic-auto correlated signal.

6. The method of claim 1 wherein the plurality of slots are from one or more of a 2G signal, a 3G signal, a 4G signal or a 5G signal.

7. The method of claim 1 , wherein a blind signal detection method is performed using a cyclic autocorrelation.

8. The method of claim 1 , wherein the plurality of client systems comprise a Launcher application, and the Launcher application is started before a start of an examination in the region.

9. One or more non-transitory machine readable information storage mediums comprising one or more instructions which when executed by one or more hardware processors cause:
identifying one or more mobile bands present in a region, wherein each of the one or more mobile bands are present in a plurality of mobile signals coming out of a mobile tower in the region;
dividing downlink frequencies of the one or more mobile bands among a plurality of frequency slots and further distributing among a plurality of client systems in time division domain, wherein the distributing is performed dynamically depending upon availability of the plurality of client systems by a central server;
detecting active channels out of the one or more mobile bands based on broadcast control channel information (BCCH) transmitted by the mobile tower in the region;
sending the BCCH information of the detected active channels back to the central server;
calculating respective uplink channel frequency corresponding to the detected active channel from the downlink frequencies;
redistributing the detected active channels among the plurality of client systems dynamically in the time division domain;
tuning a plurality of software defined radios (SDRs) associated with the plurality of client systems to the uplink channel frequencies;
capturing a raw signal generated from the SDRs in the form of binary data;
performing a cyclic-autocorrelation on the raw signal;
filtering a cyclic-auto correlated signal resulting from performing the cyclic-autocorrelation on the raw signal to remove a plurality of noises;
enhancing and extracting a plurality of features from the filtered cyclic-autocorrelated signal;
providing the extracted plurality of features to a support vector machine classifier to classify the presence of an active RF signal;
extracting a target device signal information if the active RF signal is detected;
and sending the target device signal information to the central server.

10. The one or more non-transitory machine readable information storage mediums of claim 9 , wherein the target device signal information and signal source position is calculated from the active RF signal using a triangulation method.

11. The one or more non-transitory machine readable information storage mediums of claim 9 , further comprising the step of determining bandwidth, uplink frequencies and operator information of the plurality of bands.

12. The one or more non-transitory machine readable information storage mediums of claim 9 , wherein the plurality of features include peak position, standard deviation, slope calculation and ratio calculation.

13. The one or more non-transitory machine readable information storage mediums of claim 12 , wherein the peak position is derived from the filtered cyclic-auto correlated signal and the standard deviation, the slope calculation and the ratio calculation, are derived from normal distribution of the filtered cyclic-auto correlated signal.

14. The one or more non-transitory machine readable information storage mediums of claim 9 , wherein the plurality of slots are from one or more of a 2G signal, a 3G signal, a 4G signal or a 5G signal.

15. The one or more non-transitory machine readable information storage mediums of claim 9 , wherein a blind signal detection method is performed using a cyclic autocorrelation.

16. The one or more non-transitory machine readable information storage mediums of claim 9 , wherein the plurality of client systems comprise a Launcher application, and the Launcher application is started before a start of an examination in the region.

Assignees

• Tata Consultancy Services Ltd

Inventors

• Shah Viral Prakash
• Setiya Rishi

Classifications

• H04W24/08 Primary

  Testing, {supervising or monitoring} using real traffic · CPC title

• H04B1/0003

  Software-defined radio [SDR] systems, i.e. systems wherein components typically implemented in hardware, e.g. filters or modulators/demodulators, are implented using software, e.g. by involving an AD or DA conversion stage such that at least part of the signal processing is performed in the digital domain (digital baseband systems H04L25/00; digital modulation/demodulation H04L27/00; CDMA H04B1/707; TDMA H04B7/2643; image transmission H04N5/00) · CPC title

• H04L27/0006

  Assessment of spectral gaps suitable for allocating digitally modulated signals, e.g. for carrier allocation in cognitive radio (for spectrum sharing between different networks H04W16/14) · CPC title

• H04W16/14

  Spectrum sharing arrangements {between different networks} · CPC title

• H04W48/02 Primary

  Access restriction performed under specific conditions · CPC title