Turbo code

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In <a href="/facts/Information_theory/qNLH3U5P">information theory</a>, turbo codes are a class of high-performance <a href="/facts/Forward_error_correction/cLUTUJrA">forward error correction</a> (FEC) codes developed around 1990–91, but first published in 1993. They were the first practical codes to closely approach the maximum channel capacity or <a href="/facts/Shannon%E2%80%93Hartley_theorem/nlWW6VAy">Shannon limit</a>, a theoretical maximum for the <a href="/facts/Code_rate/xPrLLTwt">code rate</a> at which reliable communication is still possible given a specific noise level. Turbo codes are used in <a href="/facts/3G/K1noBd8n">3G</a>/<a href="/facts/4G/Lfq6mSxl">4G</a> mobile communications (e.g., in <a href="/facts/UMTS/lhy2RrMw">UMTS</a> and <a href="/facts/LTE_(telecommunication)/72QhwXHT">LTE</a>) and in (<a href="/facts/Deep_Space_Network/IcapMQTR">deep space</a>) <a href="/facts/Satellite/PTX8c68t">satellite</a> <a href="/facts/Telecommunication/vxoj1cxR">communications</a> as well as other applications where designers seek to achieve reliable information transfer over bandwidth- or latency-constrained communication links in the presence of data-corrupting noise. Turbo codes compete with <a href="/facts/Low-density_parity-check_code/yPYHEKAP">low-density parity-check</a> (LDPC) codes, which provide similar performance. Until the patent for turbo codes expired, the patent-free status of LDPC codes was an important factor in LDPC's continued relevance.
</p><p>The name "turbo code" arose from the feedback loop used during normal turbo code decoding, which was analogized to the exhaust feedback used for engine <a href="/facts/Turbocharging/xuabwHlB">turbocharging</a>. <a href="/facts/Joachim_Hagenauer/Uj6ek54w">Hagenauer</a> has argued the term turbo code is a misnomer since there is no feedback involved in the encoding process.
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Turbo code open-in-new

Turbo code