Error Detection & Correction

Definition

• Error detection and correction methods are techniques used to identify and correct errors that may occur during data transmission or storage.

Characteristics

• The errors can result from various factors, such as noise, interference, or hardware issues during transmission.
• Error detection and correction methods are techniques used in various fields, including telecommunications, digital communication, networking, and storage systems, to detect and correct errors that may occur during data transmission or storage.
• The error correction methods often require additional redundancy bits, which increase the overhead in terms of bandwidth or storage.
• The choice of error correction and detection method depends on factors such as the level of error protection required, the available resources, and the characteristics of the communication channel.
• These methods vary in complexity, efficiency, and error correction capabilities. The choice of method depends on the specific requirements of the application, the expected types of errors, and the available resources.
• The choice of error detection and correction method depends on the specific application, the desired level of reliability, and the available resources.
• Different error and correction methods are suitable for different scenarios, and the choice often involves a trade-off between error correction capability, efficiency, and complexity.
• These methods help ensure data integrity and reliability.

Type of Error Detection & Correction Method

• There are some common error detection and error correction method used for transmitting data but some systems use a combination of error detection and correction methods to provide robust protection against errors.

Error Detection Method:

There are the following types of error detection methods used in data transmission and storage:-

1. Parity Bit:

   • A simple method where an additional bit of 0 and 1 is added to the transmitted data to ensure that the total number of ones (or zeros) in the data, including the parity bit, is always even (even parity) or odd (odd parity).

2. Checksum:

   • In this method, a sum or hash of the data is calculated at the sender’s end and transmitted along with the data. The receiver finally calculates the checksum on getting and compares it with the received checksum to check for errors.

3. Cyclic Redundancy Check (CRC):

   • CRC is a more advanced error detection technique.
   • It involves dividing the data by a predetermined divisor and transmitting the remainder as a checksum.
4. Automatic Repeat reQuest (ARQ):
   • ARQ involves the sender receiving acknowledgments from the receiver after sending a data block. If an acknowledgment is not received or an error is detected, the sender retransmits the data. While not a direct error correction method, it helps ensure data integrity.

Error Correction Method:

• Hamming Code:

  • Hamming codes add extra parity bits to the data, allowing to correct single-bit errors to be detected and corrected.

• Reed-Solomon Code:

  • This code is widely used in digital communication systems.
  • It can detect and correct multiple errors in a block of data.

• Forward Error Correction (FEC):

  • FEC adds redundant information to the data in a way that allows the receiver to correct errors without requesting retransmission.
  • They provide excellent error correction capabilities and are used in applications like satellite communication and wireless networks.
  • Turbo codes and LDPC (Low-Density Parity-Check) codes are examples of FEC techniques.
  • Turbo codes and LDPC codes are advanced error correction techniques used in modern communication systems.

  • Turbo Codes:

    • Turbo codes are a class of advanced error correction codes that achieve near-optimal error correction performance.
    • They use iterative decoding techniques.

• Convolutional Codes:

  • These codes involve encoding data using convolutional encoders. Decoding is done using Viterbi or other algorithms.

• Interleaving:

  • Interleaving involves rearranging the order of transmitted data to spread errors out and make it easier to detect and correct them.
  • It’s often used in conjunction with other error correction methods.

• Convolutional Codes:

  • Convolutional codes encode data in a way that allows the receiver to detect and correct errors by analyzing the pattern of received bits.

• BCH (Bose-Chaudhuri-Hocquenghem) Code:

  • BCH codes are a family of error-correcting codes that can detect and correct multiple errors.