MIT's Error Correcting Codes Will Fix Your Crappy Wireless Reception

By Andrew Tarantola on at

It doesn't matter how many signal relay towers blanket your city, the quality of your wireless reception can often change drastically — sometimes within a few steps. But MIT researchers think they've figured out how to improve reception using error correcting codes that work regardless of signal noise.

Error correcting codes (ECC) are a means of encrypting data so you can transmit it without losing fidelity, regardless of the communication channel's level of noise. It works by sending out an encrypted test message, like a codeword, to test the level of noise on a channel — the more noise in the channel, the longer the codeword needs to be. The problem is that on noisy channels, the codeword becomes prohibitively long, and on channels with fluctuating noise levels, the codeword may be too short to ensure proper transmission of the data.

MIT's solution for this problem is simple — use a single long code word broken into chunks. As Gregory Wornell, a professor in the Department of Electrical Engineering and Computer Science at MIT explains,

"The transmission strategy is that we send the first part of the codeword. If it doesn't succeed, we send the second part, and so on. We don't repeat transmissions: We always send the next part rather than resending the same part again. Because when you marry the first part, which was too noisy to decode, with the second and any subsequent parts, they together constitute a new, good encoding of the message for a higher level of noise."

Basically the system will create a codeword, break it into sections, and send each section sequentially until the receiving device has enough of the codeword to decrypt the message. It works whether the channel has just a little noise or a lot.

While still in the research phase, there are few obstacles standing between this new system and copmmercial deployment said H. Vincent Poor, dean of the School of Engineering and Applied Science at Princeton University. "The codes are inherently practical," Poor told MIT News. "In fact, the paper not only develops the theory and analysis of such codes but also provides specific examples of practical constructions." [MITNews via TNW]

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