6. Error-correcting codes

The guarantee required by operators of error rates as low as 10 ^–12 and 10 ^–15 , depending on the age of the system, is a source of many challenges. Fortunately, powerful error correction algorithms can be used to meet these stringent specifications . Such codes are already ubiquitous in all sectors of the telecommunications world, but have only been available at very high bitrates for a few years. They consist of supplementing binary information with additional bits, calculated from the information, and transmitting them along with...