ans =
'110'
Check Message Integrity
You can use the check value to verify the integrity of a message by repeating the same division
operation. However, instead of using a remainder of 000 to start, use the check value 110. If the
message is error free, then the result of the division will be zero.
Reset the remainder variable, and add the CRC check value to the remainder bits using a bit-wise OR.
Introduce an error into the message by flipping one of the bit values with bitset.
remainder = bitshift(message,divisorDegree);
remainder = bitor(remainder,CRC_check_value);
remainder = bitset(remainder,6);
dec2bin(remainder)
ans =
'1101100111011110110'
Perform the CRC division operation and then check if the result is zero.
for k = 1:messageLength
if bitget(remainder,messageLength+divisorDegree)
remainder = bitxor(remainder,divisor);
end
remainder = bitshift(remainder,1);
end
if remainder == 0
disp('Message is error free.')
else
disp('Message contains errors.')
end
Message contains errors.
References
[1] Sklar, Bernard. Digital Communications: Fundamentals and Applications. Englewood Cliffs, NJ:
Prentice Hall, 1988.
[2] Wicker, Stephen B. Error Control Systems for Digital Communication and Storage. Upper Saddle
River, NJ: Prentice Hall, 1995.
See Also
bitshift | bitxor
More About
•
“Bit-Wise Operations” on page 2-38
•
“Hexadecimal and Binary Values” on page 6-55
2 Program Components
2-46