New Channel Estimation Based Decoding Scheme for TURBO-OFDM Systems

Abstract

OFDM is an effective technique for combating multipath fading and for high-bit-rate transmission over mobile wireless channels. In using turbo codes for OFDM performance can be sufficiently improved as seen in LTE standard systems. Through this thesis, an efficient channel estimation scheme suitable for LTE standard systems is devised. We estimate the channel by considering it as a problem of estimating vectors from its linear transforms, given the initial probability. Pilot Assisted channel estimation is used with each stage of the estimator iteratively feeding the decoder, so that the algorithm breaks the feedback inside the Turbo decoder and updates the soft inputs from the channel using an updated channel estimate before each iteration. Simulations showed that the proposed joint iterative estimation and decoding technique improves the system's performance over the conventional technique.