This document discusses error detection techniques used in data transmission. It describes two types of errors: single-bit errors and burst errors. It then explains error detection, which determines if received data is correct without having the original message. Error detection uses redundancy by adding extra bits. Common error detection techniques discussed include cyclic redundancy check (CRC), which generates a frame check sequence so the frame is divisible by a number, and checksums, where sections of data are added together and complemented to check for errors.

1. Error Detection

2. George College Of Management & Science
Name-Md Abdulla Khan
Roll-16401216004
Sub-Advanced networking and
communication
Paper code-BCA-E-601-A
Assignment1
16/03/2019

3. Introduction
 Data can be corrupted during
transmission.
 Some applications require that error
be detected and corrected

4. Types of Errors
Error
Single-
Bit Error
Burst
Error

5. Single-bit error

6. Burst error

7. Error detection
Error detection means to decide whether the
received data is correct or not without having
a copy of the original message.
Error detection uses the concept of
redundancy, which means adding extra bits
for detecting errors at the destination.

8. Redundancy

9. Hamming Distance:-
The maximum distance between two words is the
number of different between the corresponding bits.
The Hamming distance can easily be found if we
apply XOR operation on the two words and count
the number of 1s in the result.

10. Example:-

12. Cyclic Redundancy Check
CRC

13. Cyclic Redundancy Check
 Given a k-bit frame or message, the
transmitter generates an n-bit
sequence, known as a frame check
sequence (FCS), so that the resulting
frame, consisting of (k+n) bits, is exactly
divisible by some predetermined
number.
 The receiver then divides the incoming
frame by the same number and, if there
is no remainder, assumes that there
was no error.

14. Binary Division

16. Checksum

17. At the sender
The unit is divided into k sections,
each of n bits.
All sections are added together using
one’s complement to get the sum.
The sum is complemented and
becomes the checksum.
The checksum is sent with the data

18. At the receiver
The unit is divided into k sections,
each of n bits.
All sections are added together using
one’s complement to get the sum.
The sum is complemented.
If the result is zero, the data are
accepted: otherwise, they are
rejected.

19. THANK YOU