DESIGN AND IMPLEMENTATION OF CONVOLUTION ENCODER AND VITERBI DECODER

Abstract: Data transmissions over wireless channels are affected by attenuation, distortion, interference and noise, which affect the receiver’s ability to receive correct information. Convolution encoding with Viterbi decoding is a powerful method for forward error correction. Convolution encoders and Viterbi decoders play an important role in digital communication especially, when channel is noisy and introduces errors in transmitted signal. The use of re-transmission methods is not efficient and has large latency measure up to the rising speed and data rates of communication links, the need of new techniques arise here to be compatible with those systems. Convolution encoding with forward error correction Viterbi decoding is designed. A Viterbi decoder uses the Viterbi algorithm for decoding a bit stream that has been encoded using Forward error correction based on a Convolutional code. The maximum likelihood detection of a digital stream is possible by Viterbi algorithm. In this paper, we present a Convolutional encoder and Viterbi decoder with a constraint length of 7 and code rate of 1/2. Implementation parameters for the decoder have been determined through simulation and the decoder should be implemented on a Xilinx FPGA Kit. Verilog HDL language is used as a design entry.

Keywords: Convolutional encoder, veterbi algorithm, decoder, FEC