Question

Cyclic Redundancy Check
Given the data bits D = 110100101011, the generator G = 110011, r = 5.

1) Find the CRC. Give the detailed steps of your computation.

2) What does the sender send?

3) Show how the receiver verifies the received data. Assume there is no error. (mostly need help with this step!)

Answer 1

Cyclic Redundancy Check (CRC) is based on binary division.

1.)

The dividend is Data-Bits + (r bits 0's) and we've divided it by CRC generator (G) .  

The CRC we got is 1000 which is the remainder.

2.)

The Sender will send (Original Data bits + CRC) ,i.e

110100101011 01000

3.)

The reciever will get the data from the sender. He will do binary division and divide the recieved data bits from the same CRC generator. If the remainder comes 0 in this case then the recieved data bits were correct or else it was wrong. If the remainder is non- zero then receiver rejects the data and asks the sender for retransmission .