Reed-Solomon List Decoder Help

This application implements a list decoder for the (31,15) Reed Solomon code. A list decoder is a decoder that corrects more errors than the code can tolerate with unique decoding. Equivalently, the decoding radius of a list decoder is greater than half the minimum distance of the code. For that specific code, the decoder can correct 9 errors, one more than 8, half the minimum distance of the code. In some (very rare) cases, the decoder will output a list of more than one codeword.

Using the list-decoder web application

The operation of the list-decoder web application is easiest following the four stage process below. However, you can also input a received word directly in the appropriate array and select Decode received word , skipping the first 3 steps.

Input information symbols

Type 15 symbols from the code alphabet in the input information symbols text box. All white spaces and excess symbols are ignored.

Encode

Select Encode information symbols and push submit. The encoder is systematic so the information symbols appear in the codeword (the solid framed part).

Add errors and erasures

On the array under Add error vector, introduce errors by inputing symbols from the alphabet. Introduce erasures by inputing the * symbol. Leave cell empty for no error. Select Add error vector and push submit.

Decode

Select Decode received word and push submit. The Decoder output area should contain output codewords and their Hamming distance from the received codeword.

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