error while using BCHencoder

Hello everyone

I would ask about BCHencoder ..

I use BCHencoder from communication toolbox , as in https://www.mathworks.com/help/comm/ref/comm.bchencoder-system-object.html

and this error come to me

Error using comm.BCHEncoder/setParameters
N and K must be positive, double precision integer scalars

all k and n are integers

this is my code

ds=randi([0 1],18,1);                                  %generating a random string
enc = comm.BCHEncoder(20,18);                           %creating Object of BCH encoder (ECC: error corecting code)
c=step(enc,ds);     

the error come from " step(enc,ds)"

i use matlab 2020b

could anyone help me how to fix the error

thank you so much

[Jorge Cadena]

I have the same issue and no idea how to resolve it. Were you able to find a solution?

Answer 1

[Pooja Kumari]

Hi,

As per my understanding, you are facing "Error using comm.BCHEncoder/setParameters N and K must be positive, double precision integer scalars" error because value of "N" and "K" are not of correct data type or value.

The value of codeword length which is represented by "N" must take the form (2^m – 1), where m is an integer in the range [3, 16]. The message length which is represented by the "K" parameter should follow this condition that "N > K" and both should be integers.

Value of "M" which is given as "20" does not satisfy 2^m-1 property.

Example code for BCHEncoder:

% Define BCH code parameters
n = 15; % Codeword length
k = 5;  % Message length

% Create BCH encoder and decoder objects
bchEncoder = comm.BCHEncoder('CodewordLength', n, 'MessageLength', k);
bchDecoder = comm.BCHDecoder('CodewordLength', n, 'MessageLength', k);
msg = randi([0 1], k, 1); % message signal

encodedMsg = step(bchEncoder, msg); % Encoding message signal

% Introduce errors
receivedMsg = encodedMsg;
errorPositions = [3, 7]; % Example error positions
receivedMsg(errorPositions) = ~receivedMsg(errorPositions); % Flip bits to introduce errors
[decodedMsg, errorStats] = step(bchDecoder, receivedMsg); %decoded message signal

% Find error locations by comparing the original encoded message and the received message
errorLocations = find(encodedMsg ~= receivedMsg);

You can refer to the documentation for more information on "BCHEncoder" :

https://www.mathworks.com/help/comm/ref/comm.bchencoder-system-object.html