Özçelikkale, AyçaDuman, Tolga M.2016-02-082016-02-082014-06-07http://hdl.handle.net/11693/26797Date of Conference: 29 June-4 July 2014Conference name: 2014 IEEE International Symposium on Information TheoryWe present lower bounds on the error probability of turbo codes under maximum likelihood (ML) decoding. We focus on additive white Gaussian noise (AWGN) channels, and consider both ensembles of codes with uniform interleaving and specific turbo codes with fixed interleavers. To calculate the lower bounds, instead of using the traditional approach that only makes use of the distance spectrum, we propose to utilize the exact second order distance spectrum. This approach together with a proper restriction of the error events results in promising lower bounds. © 2014 IEEE.EnglishInformation theoryWhite noiseAdditive white Gaussian noise channelDistance spectraError eventsError probabilitiesMaximum-likelihood decodingSecond ordersTraditional approachesUniform interleavingTurbo codesConference Paper10.1109/ISIT.2014.6875419