Secure Optical Communication using Visible and Invisible Light

The last few decades have seen rapid advances in information and communication technology. We commonly use broadband technology with high-speed Internet connectivity in our homes, offices, and mobile devices. The bandwidth and high-capacity requirements due to increased Internet, Communication, and

Project Title

Secure Optical Communication using Visible and Invisible Light

Project Area of Specialization

Information & Communication Technology

Project Summary

The last few decades have seen rapid advances in information and communication technology. We commonly use broadband technology with high-speed Internet connectivity in our homes, offices, and mobile devices. The bandwidth and high-capacity requirements due to increased Internet, Communication, and broadband services have exceeded our expectations in the twenty-first century. Optical Wireless Communication (OWC) uses visible and invisible bands of light and is considered a viable solution for realizing very high-speed and large-capacity communication links.

The prototype has been developed as our Final Year Project, which can communicate wirelessly using a visible band of light. Lasers are used as transmitters, and phototransistors are used as receivers. The laser is modulated with the help of the on-off Keying (OOK) modulation technique for transferring data through our medium. An optical carrier generates a beam of light through the atmosphere in the direction of a receiver. On the reception end, phototransistors receive the light signal, transforming the incoming light energy into an electric signal which is easily read by our microprocessor. Alignment issues are major concern in Optical Wireless Communication and this issue is minimized by increasing the effective photosensitive Surface area by using the Multiple Input and Single Output (MISO) method and by using a convex lens. Another challenge we face is to cater to the Synchronization Issue because of the delay.  We are catering to this issue by using UART communication Protocol.

With this prototype, we have achieved the speed of 7.5k bps by using a better processor like raspberry pi and code optimization. The data is secured by AES (Advanced Encryption Standard), the global standard followed worldwide.

Project Objectives

The main aim of our project is to design a product that can communicate via laser with improved data rate, Secured and better alignment technique. We will be using the OOK modulation technique to modulate the laser.

Project Implementation Method

Light can carry data in many ways, termed optical modulation techniques. In this project, we used OOK or on-off keying Modulation. In on-off keying, the light source is interpreted as binary one, and the light source off is interpreted as binary zero. The transmitter reads the binary data and accurately makes transitions of the optical component accordingly. On the other end, the receiver receives optical signals and sends binary ones and zeros according to the light source being on and off. The speed of the transmitter can analyze the speed and reliability of this whole system. Therefore laser, which has high switching capability, is used on the transmitter side, and on receiving side, phototransistors are used to detect the light.

The input is given to Raspberrypi and by using Python Programming we convert our Data into an Array of Bytes. Start, End, and Parity Bit is added to each Bytes of Array. Modified Bytes of Array are sent in the form bit of an electrical signal to the transmitter. The transmitter converts this electrical information to light or optical signals. The light signal travels in the transmission medium and reaches the receiver(Photodiode), and this optical signal is converted into electrical, that stream of Bit is Recorded and  Convert back to Bytes of Array and then its Original Form. We are using UART Communication Protocol for Sending and Receiving Data.

Benefits of the Project

• Redundant Link: Can highly improve national disaster recovery system
• Cybersecurity: Can Improve the security of Confidential Data because of Point-to-Point Secured AES (Advanced Encryption Standard) Communication.
• It Industry: Can provide cheap and portable LAN solutions.
• Video Surveillance And Monitoring: Can provide High Resolution Video Wirelessly at High Speed
• Easy to setup: Wireless network is easy to expand and setup
• Multiple Mediums – Can be used in Air as well as in Water with Minimum Interference
• Better or global coverage: It provides global reach by providing networking in places such as rural areas, battlefield, etc. where wiring is not feasible.
• Flexibility: Wireless network is more flexible and adaptable compared to wired network.
• Cost-effectiveness: Since it is easy to install and doesn’t require cables, the wireless network is relatively cheaper.
• Mobile and portable: Wireless network is easy to carry and re-install in another place.
• Mobility: It has good mobility of usage

Technical Details of Final Deliverable

The prototype of OWC is formed, which can communicate using a laser with a data rate of 7.68k bps, having significantly fewer alignment issues and using secured data. One of the major concerns was transmitter and receiver alignment; this issue is catered to greatly by increasing the surface area on the receiving side on which light is detected. We increased not only the photosensitive area but also the effective area. The photosensitive area is increased by using the array of phototransistors, and the effective area is increased by using a converging lens. In this way, our alignment issue is solved to a great extent.

Another challenge was the data rate. There are a lot of hardware delaying issues due to some additional hardware. We removed the extra hardware, due to which our data rate increased significantly. The communication protocols also have a significant effect on data rate. Therefore, we used UART. UART is a hardware-based communication protocol.As communication is done across open space, data breaches are a concern. Therefore, our data is protected using the Advanced Encryption Standard (AES) in this protocol.

This prototype is also capable of voice-to-voice communication and sending and receiving an image or any file optically. . The voice is first recorded and then the processor converts it into binary and the binary data is sent through laser bit-by-bit with the speed of 7.68k bps. The received binary information is converted back into the original file on receiving end. In this way, voice-to-voice communication and sending/receiving of an image or any file are done optically in this project. Furthermore, a Graphical User Interface is made, which will be able to send String with Advanced Encryption Standard (AES) on the Transmitter side and decrypt and show the message on the Receiver Side.

Final Deliverable of the Project

HW/SW integrated system

Core Industry

Telecommunication

Other Industries

Core Technology

Others

Other Technologies

Sustainable Development Goals

Good Health and Well-Being for People, Industry, Innovation and Infrastructure, Sustainable Cities and Communities, Life Below Water

Required Resources

If you need this project, please contact me on contact@adikhanofficial.com