Channel estimation for nonlinear OFDM system using diagonal scattered pilots <Abstract> The major drawback of the OFDM technique is its large signal dynamic caused by the high (several hundreds) number of subcarriers with random phase and amplitude, which are summed in the modulator. It results in that OFDM technique is sensitive to nonlinear distortions caused by high power amplifier (HPA). The first obvious solution is to use a very linear HPA, but this solution is expensive and consumes too much power for portable systems. In this paper, we propose a new channel estimation technique that uses diagonal scattered pi-lot tones in nonlinear OFDM symbols to estimate the channel response associated a ATTC (Advanced Television Technology Center) channel model. In the proposed scheme, pilot tones are arranged along the frequency domain, i.e, pilot tones are inserted into each OFDM symbol diagonally. For a given OFDM block, pilot tones will be scattered at all subcarriers. Results from simulation study have shown that the proposed scheme can offer a better bit error rate (BER) performance over that obtained with a conventional comb-type pilot channel estimation, which inserting pilot tones into each OFDM symbol at the same subcarriers. |