simulink simulates convolutional codes

I tried to use simulink to simulate the decoding decision of convolutional code, but the soft decision result after viterbi decoder module was very poor, and the bit error rate was very high, which was close to 0.5。

Answer 1

[Akshat Dalal]

Hi,

I understand you are simulating the decoding decision of a convolutional code using Simulink but are getting poor soft decision results and a high bit error rate.

These might be due to delays introduced by certain blocks in your model. Delays can impact the accuracy of the decoding process and lead to incorrect results.

To address this issue, you need to ensure that the ‘Receive Delay’ parameter in the ‘Error Rate Calculation’ Block is correctly defined. This parameter accounts for the delays introduced by various blocks in your model. It is important to set this parameter appropriately to align the received signals with the expected reference signals for accurate error rate calculation. You could refer the following documentation to learn more: https://www.mathworks.com/help/comm/ref/errorratecalculation.html

Additionally, you may need to manipulate delays in your model to ensure proper synchronization between the encoder and decoder. If there is a delay between the encoder and decoder, it can cause misinterpretation of code word boundaries and result in incorrect decoding. To overcome this, you can insert an additional delay of an appropriate duration between the encoder and decoder to maintain synchronization. You could refer the following documentation to learn more about delay blocks: https://www.mathworks.com/help/simulink/slref/delay.html

You could refer the following example to learn more: https://in.mathworks.com/help/comm/ug/tail-biting-convolutional-coding.html

I hope this helps.