An efficient channel tracker using pilots in OFDM systems

This paper proposes an algorithm to combat the performance degradation of an IEEE 802.11a orthogonal frequency division multiplexing (OFDM) system under the time-varying channel conditions by supplementing the conventional channel estimation method that uses a preamble. Packets in wireless local area network (WLAN) systems consist of preamble symbols for channel estimation and data symbols for traffic transmission. There are some pilots inserted within each data symbol to correct the phase error due to the frequency offset remaining even after the automatic frequency control (AFC) The proposed algorithm utilizes the pilots and requires a small amount of additional hardware. The validity of the proposed algorithm is verified by computer simulation.