Iterative channel estimation and turbo decoding for OFDM systems

In this paper, an iterative channel estimation algorithm for Turbo coded OFDM based systems is proposed. The first channel estimate is derived from the known pilots and fed to the decoder which will generate the Log Likelihood Ratios (LLR) for the decoded bits. These LLRs are used to get a better estimate of the channel, while keeping the decoder´s previously calculated parameters. The proposed technique is applied to Long Term Evolution (LTE Rel. 8) standard. Simulation results show the bit error rate (BER) performance improvement using the proposed estimator.