How error control mechanisms are designed in satellite communications

Basically, the FEC forward error correction mechanism is adopted, generally 1 2 3 4 7 8

In the digital signal of satellite communication, in order to prevent external signal interference and protect the signal from mutation, multiple error correction code settings should be carried out. In the process of decoding, digital signals are very sensitive to error signals, and as long as there are small errors per second, they cannot be decoded normally. The reason why the digital satellite signal can be smooth is due to the setting of the error correction code in the digital signal.

Forward error correction (FEC) is a very important anti-jamming algorithm in the setting of various error correction codes.

PES stream: Also known as the packaged basic stream, the basic stream ES stream is divided into packets of different lengths as needed, and the packet header is added to form the packaged basic stream PES stream. TS Stream:

Also known as transport streams, one or more programs with independent time bases are suitable for environments with a large number of bit errors. From the PES stream to the TS stream, FEC error correction codes have been added in the process, and different rates can be used, and in the DVB-S standard, 5 rates are specified 8. Taking 7 8 as an example, its practical significance is that in a TS stream, only 7 8 content is a PES stream containing program content, and the other 1 8 content is an error correction code used to protect the data stream from mutation.

The lower the FEC error correction rate, the higher the proportion of error correction codes, and the lower the threshold requirements for decoding at the same power, the smaller the antenna aperture, and the easier it is to receive. The higher the FEC, the lower the error correction code, the higher the decoding threshold, the larger the antenna aperture requirement, and the more difficult it is to receive.

The purpose of error control in communication systems is to turn an unreliable link into a reliable link.

Error control is the use of coding methods to control errors in transmission in digital communication to improve the accuracy of digital message transmission. Error Control Total Method:

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

2. Automatic retransmission request (ARQ). Emphasizing the error detection ability, it does not require the error correction ability, and the two-way channel is adopted.

3. Hybrid error correction. The above two methods are combined, but the transmission equipment is relatively complex.

In data communication, the basic idea of error control is to ensure the integrity and accuracy of the received data.

Error control is the use of coding methods to control errors in transmission in digital communication to improve the accuracy of digital message transmission.

Error control includes error detection, forward error correction (FEC), and automatic request retransmission; （arq）。

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