The blind codemaker
Error-correcting codes are one of the triumphs of the digital age. They’re a way of encoding information so that it can be transmitted across a communication channel — such as an optical fiber or a wireless connection — with perfect fidelity, even in the presence of the corrupting influences known as “noise.”An encoded message is called a codeword; the noisier the channel, the longer the codeword has to be to ensure perfect communication. But the longer the codeword, the longer it takes to transmit the message. So the ideal of maximally efficient, perfectly faithful communication requires precisely matching codeword length to the level of noise in the channel.Wireless devices, such as cellphones or Wi-Fi transmitters, regularly send out test messages to gauge noise levels, so they can adjust their codes accordingly. But as anyone who’s used a cellphone knows, reception quality can vary at locations just a few feet apart...