OFDM Physical Layer Implementation for the Kansas University Agile Radio

This thesis details the development of an Orthogonal Frequency Division Multiplexing (OFDM) reference design system based off of the IEEE 802.16-2004 OFDM PHY standard. This system consists of a separate transmitter and receiver and has been implemented in VHDL for use on the Kansas University Agile Radio (KUAR). The KUAR is an experimental software-defined radio platform that is intended for research in frequency-agile and cognitive radios. OFDM is a pertinent modulation technique for frequency-agile and cognitive radios, in that it can facilitate the ability to perform dynamic spectrum access communications over a wide transmission bandwidth without interfering with incumbent license holders. This thesis contributes an actual implementation of the basic components required for an OFDM system. Timing and frequency synchronization, channel estimation, and pilot carrier phase tracking are mandatory components of a packet-based OFDM system and pose the most significant implementation challenge. The VHDL modules provide a proof of concept and a framework unto which more sophisticated algorithms can be later developed and tested. Another key contribution is the demonstration of a design-flow for developing and validating communication systems in VHDL. A sequence of testing and validation phases is discussed, progressing from Matlab simulation to VHDL simulation to synthesized VHDL testbenches and eventually to across-the-air