Projects:2014S1-33 Software-Defined Radio for VLF Transmission

Introduction

Environmental sensing is an emerging industry which will shape and support human activities. Large sensor networks exist to gather vital soil information such as soil moisture and salinity. Wired communication between sensor nodes is very cumbersome and infrastructure heavy. In contrast, standard wireless protocols in the microwave region require significant power and reduce battery life. In this project, the Very Low Frequency (VLF) range (30 kHz) has been sought as an alternate method of transmission. Additionally, Software-defined Radios (SDRs) have been used for both the transmitter and receiver. The use of an SDR allows for reduced hardware complexity and lower power consumption. Digital and analogue circuitry, a loop antenna and software have all been addressed to construct the system.

Project Background

What is VLF?

• Standard defined by International Telecommunication Union (ITU)
• Frequency range 3 kHz to 30 kHz
• Wavelengths from 10 Km to 100 Km

What is an SDR?

• Radio components implemented in software
• Digital components replace analogue
• Interface with analogue world
  • ADC and DAC conversion
• Processing takes place in digital domain
• Adaptable and customisable
  • Wide range of applications
• Ideally support:
  • Any waveform
  • Any carrier frequency
  • Any bandwidth
  • Any modulation technique

The Significance

• Re-configurable
• Upgradable
• Software re-use and duplication
• Adaption to environment
• Significantly lower power requirements than traditional radio

Project Scope

• New project in 2014
• SDR for VLF transmission
• Conduct a proof of concept
• Design and verify software algorithms
• Implement software onto Microcontroller
• Design, build and test analogue circuitry
• Implement SDR onto PCB
• Integrate SDR, RF Front End, Antenna and Soil Sensor

Personnel

Team Members

• Mr. Matthew Baronian
• Mr. Alex Coleman
• Mr. Jock Duncan

Supervisors

• Dr. Thomas Kauffman
• Prof. Christophe Fumeaux