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Turbo Codes Promise Better Wireless Transmission

Posted by timothy on from the squashing-things-down dept.

captain igor writes "IEEE is running a story about two French professors that have created a new class of encoding, called 'Turbo Codes,' that will allow engineers to pass almost twice as much data through a given communications channel, or equivalently, the same amount of data at half the power. The new codes allow the Shannon Limit (the theoretical maximum capacity of a channel) to be approached to, currently, within .5 dB. Scientists hope that this breakthrough will revolutionize wireless communications, especially with the coming reclamation of large swaths of the EM spectrum." As the article points out, such codes are in use now, but seem poised for much wider implementation.

5 of 212 comments (clear)

  1. turbo codes aren't new ... by Anonymous Coward · · Score: 0, Redundant

    ... they've been around for a little over a decade (11 years). It just irks me when I read something on an otherwise quasi-technical website, and see people hailing this "new technology" which has been around -- and in use (surprise!) -- for years.

  2. Hardly cutting edge news by grahamsz · · Score: 1, Redundant

    Whilst turbo codes are cool, as the article points out they were developed in 1993. I graduated last year and we covered them on my course.

    Now they are a fairly obvious choice in any digital communications system and it's hardly groundbreaking that someone has chosen to use them.

  3. Has it something to do with signal sampling? by Nicolas+Pillot · · Score: 0, Redundant

    I know Shannon as someone who tells we need to sample a signal at rate which is minimum twice the highest frequency found in the sampled signal. Is this related to that ?

    I can't quite understand what turbo codes are, and if there is no relation, well .... yeah, i'd be off-topic ;)

    1. Re:Has it something to do with signal sampling? by lightspawn · · Score: 0, Redundant

      when you detect an error (the redundant bit doesn't match the proper sequence), you back-trace through your data and find the most likely non-errored sequence and adjust your data bits accordingly.

      From my admittedly limited exposure to turbo codes, it seems there are no redundant bits and the algorithm never detects an error per se. Instead it always backtracks to find the most likely sequence. Hence the huge performance demands - this analysis needs to happen for every possible state of the encoder for every bit, times multiple iterations (the more you do, the closer to the limit you get).

  4. STOP USING THE WORD "TURBO" by osjedi · · Score: 0, Redundant



    This is one of my biggest peeves. Unless the power output of your product is increased by using a turbine pump, driven by exhaust gasses to increase the density of the intake charge IT'S NOT A TURBO. STOP USING THE WORD TURBO TO DESCRIBE ANY DESIGN OR PERFORMANCE IMPROVEMENT!!!!!!
    I'd think a pair of professors could do better than that, French or not.

    --
    -=-=-=-=- osjedi uses Debian GNU/Linux. -=-=-=-=-