Performance evaluation of Variable Threshold decoding on self-orthogonal convolutional codes

In communication theory, researchers are always trying to find fast and least complex decoding technique. Threshold decoding (TD) is such an easily implementable decoding technique to any modern communication system. Variable Threshold MTD (VT-MTD) is an improved version of conventional MTD system. The performance of hard decision and soft decision variable threshold decoding has been presented in this paper. Here, self-orthogonal convolutional codes are used for simulation. The proposed variable threshold hard decision decoding (VT-HMTD) produces 0.40dB coding gain at BER of 10^-5 compared to HMTD system. Also, variable threshold soft decision decoding (VT-SMTD) gives 0.80dB coding gain at BER of 10^-5 compared to soft decision technique. Both of these proposed algorithms give 4.5dB coding gain compared to the uncoded system.