Development of Efficient RF-System for Short Range Denial-of-Mobile-Service in Classrooms

Project Title

Development of Efficient RF-System for Short Range Denial-of-Mobile-Service in Classrooms

Project Area of Specialization Electrical/Electronic EngineeringProject Summary

In recent years, the use of mobile phones has increased, undoubtedly. Most of the population (including students of universities and colleges) use it due to its wide range of applications. While it brought countless benefits in our daily life, its over-addiction and usage at undesired places have significant negative impacts like reduced work efficiency, social gap between families due to lack of personal attention, physical and psychological problems. According to a survey conducted by the US National Library of Medicine in 2016, 24.8%-27.8% [*] of students are addicted to mobile phones and this percentage is increasing every year.

The university environment, which is the hub of learning through social interactions, is severely affected by such addiction. Most affected places in the universities are the lecture halls, seminar rooms, and libraries where students’ attention and focus is vital for their learning and grooming. The obsession of checking mobile phones after short intervals of time at these places results in a distraction and eventually affect the learning processes. According to a report by the psychology department of Harvard, an average person takes 21 minutes to regain full concentration [?].

Although the complete denial of mobile service is not feasible within the entire university premises, it can be implemented at the desired places where concentration is necessary, like inside classrooms and libraries. Human psychology tells that an average person is automatically triggered to check his/her phone after a certain interval of time even if he/she is not expecting any kind of notification. The availability of such denial of mobile service at these designated places will enable the uninterrupted environment, resulting in an increase in concentration levels and better opportunities of learning and interaction.

The project aims to design a short-range on-chip system for denial of mobile service. The proposed system generates a noise signal at the same frequency as that of a GSM signal but with higher power to block the communication signal. We tested a prototype of our circuit which successfully blocked mobile communication. Restricting mobile communication inside a classroom could be easily achieved resulting in improved concentration levels.

*https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5680647/  

Project Objectives

1. Development of short-range system for the denial of mobile service at designated places in the university environment.
2. Implementation of the complete hardware on a single portable chip to make it easy to deploy and use.
3. Provide an efficient solution that can be implemented for other relevant applications like at religious places, hospitals, petrol stations, meeting halls etc.
4. Enabling productive and learning environment for students through enhanced concentrations and social interactions.
5. Enabling uninterrupted environment for quite places like library.
6. Prevent cheating done during exams using mobile phones.

Project Implementation Method

Mobile communication jammer can be divided into two sections; IF and RF section.

IF Section

The IF section consists of three parts:

1. Noise signal
2. Ramp signal (triangular wave); using 555 timer
3. Adder

A noise circuit would generate a noise signal using the concept of the avalanche effect in diodes. The picture below shows the signal generated by the circuit implemented in this project.

A ramp signal would be generated so that VCO can use it to sweep the noise signal to the desired frequency range which is a GSM band in this case. The adder would add the noise signal and the ramp signal.

RF Section

Once the noise signal and ramp signal are added we proceed onto the RF section. The RF section consists of three parts:

1. Voltage-controlled oscillator (VCO)
2. Monolithic Amplifier
3. Antenna

The output of the IF section would be the input of the RF section. The amplifier would amplify the signal so that the jamming range can be increased and if the signal has attenuated, it would be amplified. The antenna would be used to propagate the signal resulting in jamming the mobile signal within a specific range.

Benefits of the Project

1. Short-range system for the denial of mobile service at designated places in the university environment.
2. Complete hardware on a single portable chip to make it easy to deploy and use.
3. avalibility of  an efficient solution that can be implemented for other relevant applications like at religious places, hospitals, petrol stations, meeting halls etc.
4. Enabling productive and learning environment for students through enhanced concentrations and social interactions.
5. Enabling uninterrupted environment for quite places like library.
6. Prevent cheating done during exams using mobile phones.

Technical Details of Final Deliverable

IF section woudl generate noise using avalanche effect in diodes and add it with a ramp signal. We are using the following components in the IF section:

Components	Function	Voltage Range
Noise Circuit	Generating noise signal	Up to 1.5V
Timer IC	Generating a ramp signal	7V-14V
Adder	Adding noise and ramp signals	5.5V-15.5V (adder output)

The noise signal would be swept in desired band and amplifed by the RF section. For the RF section, we are using the following components:

Components	Function	Max. Voltage	Gain	Output Power
VCO	Sweep the noise signal frequency to the desired range	6V	-	6 dBm
CMA-545G1+ (Monolithic Amplifier)	Amplify the signal to increase the range for jamming	6V	31.8 dB	22 dBm
Antenna	Propagation of the jamming signal	-	6 dB	-

Components

Noise Circuit

Timer IC

Adder

Components

VCO

CMA-545G1+ (Monolithic Amplifier)

Antenna

Final Deliverable of the Project Hardware SystemCore Industry TelecommunicationOther IndustriesCore Technology OthersOther Technologies OthersSustainable Development Goals Quality EducationRequired Resources

Components	Function	Max. Voltage	Gain	Output Power
VCO	Sweep the noise signal frequency to the desired range	6V	-	6 dBm
CMA-545G1+ (Monolithic Amplifier)	Amplify the signal to increase the range for jamming	6V	31.8 dB	22 dBm
Antenna	Propagation of the jamming signal	-	6 dB	-