Take it to the limit

摘要

Noise is the blight of the information age. It can be far more than an annoyance: if you send instructions to an interplanetary spacecraft, and the message gets scrambled going through the ionosphere, your probe might fire its engines at the wrong time. But now noise has met its match, in the form of two miraculous methods for pulling clear messages out of what was previously considered to be undecipherable static. It's like hearing a whisper in a thunderstorm or reading road signs in a blizzard. These static-bashing technologies, called turbo codes and LDPC codes, are already on their way into your home, programmed into digital TV receivers and computers with third-generation wireless. They are also on their way to Mercury and will soon be used on spaceships bound for Mars.