Synchronization schemes for packet OFDM system

Abstract

A complete OFDM synchronization chain is proposed based on practical synchronization schemes. The synchronization is accomplished in three steps: frame detection (or timing), frequency offset estimation, and phase tracking. For frame detection, time-domain differential PN sequence is used. For frequency offset estimation, time-domain correlation of adjacent pilot symbols estimates the fractional part of the frequency offset and frequency-domain differential PN sequence is used to find the integer part. The phase offset due to frequency offset estimation error as well as the phase noise is tracked using a digital phase lock loop.