The advantages and disadvantages of each error control method for data communication are as follows:
The following are the main types of error control methods in data communication:
Odd parity: This is one of the simplest error control methods. It does this by adding an extra bit to the data so that the number of 1's in the entire data (including the extra bit) is either even (even parity) or odd (odd parity). At the receiving end, the number of 1's in the data can be checked to see if the number of 1's in the data is as expected, thus detecting individual bit errors. However, the disadvantage of this approach is that if more than two bits are in error in the transmission, the error cannot be detected.
Cyclic Redundancy Check (CRC): CRC is a more advanced form of error control. It calculates the CRC value of the data at the sending end and appends this value to the data to be sent along with it. At the receiving end, the CRC value of the received data is again calculated and compared with the received CRC value. If they are the same, the data is considered correct.CRC can detect multi-bit errors and has a high error detection capability. However, the process of calculating the CRC is relatively complex and requires additional computational resources.
Automatic Retransmission Request (ARQ): ARQ is a feedback-based error control method. At the sending side, if a data transmission error is detected, a request is sent to the receiving side to retransmit the data. At the receiving end, if an incorrect data is received, a request is returned to resend the data.ARQ is suitable for occasions where the error rate of data transmission is high, and it can guarantee the correctness of the data. However, if the network condition is poor, it may cause a delay in data transmission.
Forward Error Correction (FEC): FEC is a type of error control that adds redundant information to data to detect and correct errors. It is commonly used in wireless communications such as Wi-Fi and cellular networks. At the transmitter side, redundant information is inserted based on the errors in the data block, allowing one bit of error to be detected and corrected for each data block.
At the receiving end, the received data is corrected using the same algorithm.The advantage of FEC is that it corrects single-bit errors and reduces the reliance on retransmission to some extent. However, it requires additional bandwidth to transmit redundant information and may not work well for high error rates.
These are just a few of the error control methods used in data communications and their advantages and disadvantages. Which one to choose depends on factors such as the application scenario, transmission rate, error rate, and available resources.