Question

Given a CRC protocol, assuming that both a sender and a receiver agree to adopt
the generator polynomial x 4 +x+1, if the sender is to send out data string 10101001, what
would be the transmitted bit string T (i.e. the data stream plus parity bits)?

Answer 1

The polynomial is x^4+x+1, can be written as, 10010

Power 4 3 2 1 0

-----------------------

Binary 1 0 0 1 0

The original message is 10101001

The transmitted would be 10101001XXXX

The last XXXX can be found out by the remainder 10101001 with 10010 polynomial.

note : Using XOR rules we can obtain the results.

__111______________

10010 / 10101001

10010

----------------

11100

10010

-------------

11101

10010

-------------

1111 = Remainder.

So the Transmitted message is 10101001111