Implementation of Turbo Codes for Noisy Channels in LTE Systems

Abstract

Turbo codes can be viewed as a class of parallel concatenation of convolution codes which attain low Bit Error Rate in the waterfall region of the error even for relatively low Signal to Noise Ratio values. This paper presents an implementation of turbo codes. The approach used in this paper uses a recursive convolution encode due to good convergence of decoding at the receiving end. Block interleaving has been used to randomize or permute the bit stream. Puncturing has also been implemented to generate higher rate codes compared to the conventional r=1/3 encoder. This helps in generating higher rate turbo codes for noisy channels. Finally the decoding mechanism uses the soft input-soft output decoding. The performance of the system has been evaluated based on the bit error rate.