Channel Estimation and Mitigation Techniques for OFDM in a Doppler Spread Channel
The performance of OFDM modulation degrades in a Doppler spread channel due to Inter-Carrier Interference (ICI). Multirate sampling theory and a detection scheme, called Sequential Interference Cancellation (SIC), are applied to a standard OFDM system to reduce ICI. The increased sampling rate (upsampling) causes less ICI for the edge subcarriers. The SIC detection scheme recovers the data from the outer carriers first and then detection moves from the outer carriers to the inner carriers to lower the error floor. In this paper, SIC detection with modified time-domain interpolation estimation is presented and its performance is compared to the existing time-domain and low-pass interpolation channel estimations via computer simulation.