Added pilot semiblind iterative channel estimation for OFDM packet transmission

Orthogonal frequency division multiplexing (OFDM) is a promising technique for achieving high bit-rate transmission in radio environments. Various techniques to estimate channel attenuation have been proposed for OFDM transmission. In these techniques, the added pilot semiblind (APSB) channel estimation has been proposed, which does not require any additional bandwidth. For an OFDM packet transmission that includes preambles, it is difficult to track the channel variation of the latter of packet due to time-varying channels in fast fading environments. We expect that channel estimation is improved by applying the APSB channel estimation technique to the last symbols of packets. In this paper, we propose an OFDM packet transmission system with APSB channel estimation technique to track the variation of channel attenuations. We show that the proposed system can track the channel variation and achieve better performance than the conventional system in fast fading channels.