Optimal Pilots for Frequency Offset and Channel Estimation in OFDMA Uplink

Abstract

Optimal pilots design and placement for the frequency offset and channel estimation in orthogonal frequency- division multiplexing access (OFDMA) uplink systems are proposed. The received pilots of multiple users can always be demodulated, even if they are totally overlapped due to the large frequency offsets. With the knowledge of channel state information (CSI) at the receiver, the performance of the proposed frequency offset estimation is robust to the channel estimation errors. The frequency offset and CSI can be jointly estimated by employing the proposed pilots.