Transmission Error Detection

[Emanresu]

Hi,

I have a small fixed size packet of information that I want to transmit and detect errors with a high degree of confidence (no correction is required). I'm guessing that a CRC is probably the way to go but don't know how to work out what form of CRC to use. I want to be able to specify a value for the likelihood of failure to detect an error.

If for example I wanted the likelihood of failure to detect an error to be 1 in a billion when the probability of an error is high, say 10%, how do I work out how to achieve this ?

E.

 

[mgb_phys]

Shannon's theorem http://en.wikipedia.org/wiki/Shannon's_theorem tells you how much error correction you need for a given degree of failure on a noisy channel.
In practice it largely depends on if you expect the noise to be fairly constant, changing bits in each word, or bursty, corrupting long sequences of data.
The wiki link has good links to different error correcting codes.

 

[tacman]

Hi E,

Thank you for your question. You are correct that a CRC (Cyclic Redundancy Check) is a commonly used method for error detection in data transmission. It works by generating a checksum, or a unique value, based on the data being transmitted. This checksum is then sent along with the data and is used by the receiver to compare with the checksum it calculates from the received data. If the two checksums match, it is assumed that the data was transmitted without any errors. However, if the checksums do not match, it indicates that an error has occurred during transmission.

To determine what form of CRC to use, you will need to consider the length of your data packet and the level of error detection you require. There are different types of CRCs, each with a different number of bits used for the checksum. Generally, the longer the checksum, the higher the likelihood of detecting errors. You can use online CRC calculators to determine the appropriate CRC for your specific needs.

In order to achieve a likelihood of failure to detect an error of 1 in a billion when the probability of an error is 10%, you will need to use a CRC with a longer checksum. This will increase the chances of detecting errors, but keep in mind that there is always a possibility of errors slipping through, even with a highly reliable CRC. It is also important to note that the likelihood of failure to detect an error is also affected by factors such as the quality of the transmission channel and the sensitivity of the receiving equipment.

I hope this helps answer your question. Good luck with your data transmission!