What is fec

Forward error correction FEC has been a powerful tool in the cable industry for many years. Similarly, FEC has also become an indispensable element for high-speed optical transmission systems, especially in current coherent optical transmission age. FEC is an effective digital signal processing method that improves the bit error rate of communication links by adding redundant information parity bits to the data at the transmitter side so that the receiver side then uses the redundant information to detect and correct errors that may have been introduced in the transmission link.

As the following figure shows, the signal encoding that takes place at the transmitter has to be properly decoded by the receiver in order to extract the original signal information. Precise definition and implementation of the encoding rules are required to avoid misinterpretation of the information by the receiver decoding the signal. Successful interoperability will only take place when both the transmitter and receiver follow and implement the same encoding and decoding rules.

As you can see, FEC is the essential element that needs to be defined to enable the development of interoperable transceivers using optical technology over point-to-point links. The industry trends are currently moving toward removing proprietary aspects and becoming interoperable when the operators advocate more open and disaggregated transport in high-volume short-reach applications. When considering which FEC to choose for a new specification, you need to consider some key metrics, including the following:.

The common mechanism for increased NCG was the use of concatenated coding schemes with iterative hard-decision decoding. The following table summarizes performance metrics for standardized FEC in optical fiber transmission systems. CableLabs is the first specification organization to demonstrate G coherent optics interoperability with a significant level of participants.

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News and announcements All news. Events and deadlines Full calendar. This is necessary as most data centers are already at maximum capacity. The use of PAM4 signaling has changed Ethernet test requirements. FEC is an advanced coding technique that sends the required information to correct errors through the link along with the payload data. FEC is especially beneficial in applications where retransmissions are costly or impossible, such as one-way communication links and transitions to multiple receivers in data centers.

The FEC technique controls errors in data transmissions over unreliable or noisy channels. FEC transforms transmitted data message sequences into code words that include redundant data. The receiver decoder uses the added redundancy to detect and correct errors that may occur in the message, minimizing the need to retransmit. The key measurements affected by FEC test implications include the transmitter output and receiver input burst error counting and analysis.