Reliable region decision DDCE and erasure replacement decoding of OFDM system

We propose an enhanced channel estimation algorithm that predicts channel with smaller number of pilots and less computational complexity than conventional algorithms on the multipath Rayleigh fading channel. The presented algorithm is based on Decision Directed Channel Estimation (DDCE). And it is made up of two parts: i) Reliable Region decision (RR) - it identifies reliable region by using characteristics of DDCE scheme; ii) Erasure Replacement decoding (ER) -it replaces data in unreliable region with erasure bit, and improves BER performance after Viterbi decoding. And we define ‘ information error rate ’ (IER) as a measure of information transmitted to the decoder. By using IER, the coded BER performance of system can be evaluated before the coding procedure. We show that a hard decision with ER has better performance than the conventional soft decision scheme. From simulations, we observe that RR DDCE with the ER scheme performs much better than a general DDCE system.