FPGA implementation of an OFDM PHY

Orthogonal frequency division multiplexing (OFDM) based communication is increasingly being used in environments that exhibit severe multipath. While there are ASSP solutions for many common (e.g. 802.11a) and emerging standards, many communication systems, for example a military software radio, demand flexibility. The arithmetic requirements of an OFDM system can be very demanding. Even the ubiquitous 802.11a WLAN system has arithmetic requirements in the billions-of-operations per second region and cannot be satisfied even by high-end DSP microprocessors. This paper reports on the FPGA implementation of an OFDM transceiver. In addition to the FFT based modulator and demodulator, receiver synchronization and channel estimation is discussed. The FPGA resource requirements of the various sub-systems is reported and the design methodology employed for system design, verification and FPGA implementation is described.