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Graphical User Interface for Simulating Convolutional Coding with Viterbi Decoding in Digital Communication Systems using Matlab

Ezeofor C. J., Ndinechi M.C.

This paper presents Graphical User Interface (GUI) for simulating convolutional coding with Viterbi decoding in digital communication system using MATLAB. Digital transmission is not free from channel impairments such as noise, interference and fading which cause signal distortion and degradation in signal to noise ratio. These introduce a lot of errors on the information bits sent from one place to another. To address these problems, Convolutional coding is introduced at the transmitter side and Viterbi decoding at the receiver end to ensure consistent error free transmission. In order to visualize the effect and evaluate the performance of the coding and decoding used, simulation programs that encode and decode digital data were designed, written and tested in MATLAB. The generated bit error rate (BER) is plotted against Energy per bit to noise spectral density (Eb/No) for different digital input data. It is seen that as Eb/No increases, bit error rate decreases thereby increasing the performance of the convolutional code rate used in the transmission channel at both end. Further analysis and discussion were made based on the MATLAB graph results obtained.