Electronic Theses and Dissertations


Implementation of a Software Defined Spread Spectrum Communication System


Mir Ali

Date of Award


Document Type


Degree Name

M.S. in Engineering Science

First Advisor

John N. Daigle

Second Advisor

Allen Glisson

Third Advisor

Lei Cao


The goal of this thesis is to develop a framework to prototype a software defined direct sequence spread spectrum transceiver that can be used as a node in an ad hoc network. We introduce the concept of a software radio, the current state of art, and GNU Radio and its concepts. We discuss in detail the design and development methods of GNU Radio and develop a flowgraph in Python to demonstrate the method of development. We present a mathematical analysis of (DSSS) modulation and demodulation schemes along with the transmitter and receiver design. We use this design to develop an analogous design in GNU Radio using the signal processing blocks that are present in GNU Radio and ones we develop. We perform simulations and tests to validate the algorithms, signal processing blocks and flowgraphs that we developed. We find that the signal acquistion algorithm is capable of determining the code and frequency offset in a received (DSSS) signal. We also find that the carrier tracking loop is capable of tracking the received carrier when the signal has a high (SNR). We conclude that GNU Radio as a technology can be used to prototype transceivers that are highly configurable and expandable. Finally, we identify and suggest some possible areas where this design can be developed and improved further.


Electrical Engineering

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