Time and Frequency Synchronization for Hiperlan/2

The Hiperlan/2 standard [1]-[3] for wireless LAN transmission in the 5 GHz frequency band makes use of OFDM modulation with a TDMA access scheme, in order to efficiently exploit time dispersive channels with frequency selective fading. It is well known that the performance of OFDM schemes is very sensitive to synchronization: symbol timing and carrier frequency errors must be carefully estimated and corrected at the receiver. We propose a scheme for time and frequency offset estimation, derived form those presented in [4]-[7], suited to all the transmission burst types of the standard. The scheme makes use of the periodic structure of each burst preamble and is robust with respect to distortions induced by dispersive channels. We evaluate its performance both via statistical analysis and simulation in the presence of AWGN and dispersive channels, and also present an original technique for performance evaluation of the timing synchronization in dispersive environments, based on the cumulative distribution function of the useful signal power after demodulation.