Volume 4, Issue 1

Efficient decoding algorithm for convolution coding used in communication systems

Author

Bh. Sirisha* and B. Venugopal

Abstract

Convolution encoder and Viterbi decoder are the basic and important blocks in any Code Division Multiple Accesses (CDMA). They are widely used in communication system due to their error correcting capability but the performance degrades with variable constraint length. In this context to have detail analysis. The best way of decoding against random errors is to compute the received sequence with every possible code sequence. This is called maximum likelihood (ML) decoding. The criterion for deciding between two paths is to select the one having the smaller metric. The rule maximizes the probability of a correct decision. The Viterbi algorithm occupies large memory and computational resources. To address this problem Proposed Viterbi Algorithm is introduced. The Proposed Viterbi decoder functionally is same as the previous Viterbi decoder but it reduces memory and the hardware resources. The proposed block diagram checks every node for path metric value and eliminates the path that is found if it is not having minimum distance. This paper deals with the implementation of convolution encoder and Viterbi decoder for fixed constraint length. It uses a fixed constraint length of 8 bits for ½ code rate. By analysing the Viterbi algorithm it is seen that our algorithm has a better error rate for ½ code rates than 1/3. The reduced bit error rate with increasing constraint length shows an increase in efficiency and better utilization of resources as bandwidth and power.

DOI

https://doi.org/10.62226/ijarst20150194

PAGES : 271-275 | 32 VIEWS | 78 DOWNLOADS

Download Full Article