Pilot Designs for Consistent Frequency Offset Estimation in OFDM Systems

This paper presents pilot designs for consistent frequency offset estimation of OFDM systems in frequency-selective fading channels. We describe two design approaches, namely consistency in the probabilistic sense and absolute consistency. Existing preambles and pilot designs in the literature do not guarantee the absolute consistency. We derive general criteria for both approaches, present sufficient conditions on the pilot structures, and derive simple pilot designs satisfying these conditions. Absolute consistency should not be compromised in emergency-related or other critical communication scenarios and our proposed consistent pilot designs address this need.