Improved Low Complexity Hybrid Turbo Code: A Modified Turbo Code

Turbo convolutional codes (TCC) are excellent error correcting codes as they show near Shannon capacity performance in communication systems. However, turbo decoders are computationally complex. Recently, a class of modified turbo codes called low complexity hybrid turbo codes (LCHTC) is proposed with bit error rate (BER) which is almost same as that of turbo codes. In this paper improved low complexity hybrid turbo codes (ILCHTC) and its BER performance is presented. Simulation results show that BER performance and error convergence of ILCHTC is better than that of LCHTC. Analysis of ILCHTC and LCHTC decoders show that the number of computations reduce by a factor of two as compared to those required by the decoder of TCC. Decoder complexity of TCC remains unchanged if puncturing is used for code rate adjustment unlike LCHTC and ILCHTC in which code rate is adjusted by changing the parameters of encoders.