Adaptive pre-equalization in analog heterodyne architectures for wireless LAN

The IEEE802.11a wireless LAN standard defines a high system performance and therefore requires a certain signal accuracy for the OFDM transmitter output. Taking the potential analog low, medium IF and RF filter imperfections into account, it is necessary to pre-equalize the signal stream digitally before transmitting. The paper concentrates on the description of the OFDM transmitter front-end architecture and the adaptive decision-aided pre-equalization in the digital domain. The mathematics of the pre-equalization process are derived from the well known post-equalization respective channel-equalization case. Finally simulation results are presented.