Data Can Be Corrupted During Transmission

Data can be corrupted during transmission. For reliable communication, errors must be detected and corrected.

Single-Bit err vs Burs err --> only 1 err vs more than 1

Error detection uses the concept of redundancy, which means adding extra bits for detecting errors at the destination.

CRC is one of Detection Method (lain²: parity check [vrc + lrc], checksum)
crc use polynomial as divisor. e.g. x7 + x5 + x² + x + 1 --> 10100111

b4 sent, generate remainder as redundant bit.
e.g data=100100 divisor=1101

then sent data+remainder

receive.. (data+remainder) divide 1101 must get remainder '0'. else --> error.
in data correction, can use Hamming Code.

place a redundant bit to take care of every single bit of data..
then put the redundant bit.. r8, r4, r2, r1
do check.. if error, calculate which bit is error...