In data communications, what are basically two methods of using coding for error control?

In data communications, there are basically two methods of using coding for error control, namely: "Automatic Repeat Request ARQ" and "Forward Error Correction FEC". The automatic repeat request (ARQ) method emphasizes error detection capabilities and does not require error correction capabilities, and is used for bidirectional channels; the forward error correction FEC method has good real-time performance and is used for simplex communication.

The operating environment of this tutorial: Windows 7 system, Dell G3 computer.

In data communications, there are basically two methods of using coding for error control, namely: "Automatic Repeat Request ARQ" and "Forward Error Correction FEC".

Error control is a technology that uses coding methods to control errors generated during transmission in digital communications to improve the accuracy and effectiveness of transmission. Error control includes error detection, forward error correction (FEC) and automatic request for repeat transmission (ARQ).

According to the different nature of the error, error control is divided into error control for random errors and error control for burst errors. Random errors refer to channel errors that are relatively evenly distributed at different time intervals; burst errors refer to channel errors that are concentrated in a short period of time. Sometimes several error control methods are mixed and used, and certain error control capabilities are required for both random errors and burst errors.

A method to ensure that the received data is complete and accurate. Because actual phone lines are always imperfect. Data may become garbled or lost during transmission. To catch these errors, the sending modem performs a mathematical operation on the data to be sent and sends the result along with the data. The receiving modem performs the same operation on the data it received and compares the two results. . If the data is corrupted during transmission, the two results will be inconsistent, and the modem receiving the data will request the sending end to resend the data.

Errors in the communication process can be roughly divided into two categories: one is random errors caused by thermal noise; the other is sudden errors caused by conflict noise. Sudden errors affect the local area, while random errors affect the whole world.

Error control method:

1. Forward error correction. Good real-time performance, simplex communication is adopted.

2. Automatic repeat request (ARQ). Emphasizes error detection capabilities, does not require error correction capabilities, and uses two-way channels.

3. Hybrid error correction. A combination of the above two methods, but the transmission equipment is relatively complex.

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