FPGA Implementation of Real-OFDM HF Modem with Fine frequency Offset Estimation

In this paper, implementation of an orthogonal frequency-division multiplexing (OFDM) HF modem is presented. The advantage of This modem compared with typical OFDM systems is to remove quadrature component(Q) by usingOFDM with real value output(Real-OFDM). frequency offset synchronization of the this modem in the HF channel using Hilbert transform, is done by a low complexity fine frequency offset estimation algorithm that it is appropriate for implementing on the FPGA. Using this method, frequency offset can be estimated twice of the subcarrier spacing at very low signal-to-noise ratios (SNR’s) and with appropriate mean square error (MSE).The proposed modemisimplemented on the Virtex-4 XC4VLX25 device and optimal resource utilizationis achieved.