OFDM symbol shaping for reducing D/A requantization error in multiband UWB systems

We propose a mixed-mode orthogonal frequency domain multiplexing (OFDM) symbol shaping scheme to reduce digital-to-analog (D/A) requantization error in multiband OFDM ultra-wideband (UWB) systems. This method enhances system BER performance without reducing quantization step size. Otherwise, it can decrease D/A converter implementation complexity while maintaining the same system BER. We show that the D/A requantization error is reduced by digital-domain OFDM symbol scaling before D/A conversion and analog-domain inverse scaling after D/A conversion. This scheme gains more efficiency as the average PAR (peak-to-average-power ratio) of OFDM symbols increases. Simulation results show SNR improvement by the proposed scheme in IEEE P802.15.3a-compliant 480-Mbit/s UWB transmission.