An Analysis of Computational Complexity of Low Level Quantizers for Block Turbo Decoding for Product Codes of Binary Linear Code Block Turbo Decodings (BTDs) with SoftIn SoftOut (SISO) decodings for twodimensional product codes of linear codes can achieve good error performance. However, since large computational complexity of the BTDs can be a problem, a method which can reduce average computational complexity is needed. In this research, the authors focus on an early termination condition as the method for the reduction on the computational complexity. From the tendency of the output of SISO ordered statistics decoding, a condition is proposed. Based on simulation results for the twodimensional product code of the (32,26,4) ReedMuller code, analysis on a parameter of the condition are given. The results show that the computational complexity can be reduced to more than one fourth at the SN ratios higher than 7dB of EbNo without degradation on error performance by choosing an appropriate parameter.

An Enhanced Method for Turbo Code Interleavers Design of interleaver for turbo codes to achieve excellent BER performance is a very difficult task. The bruteforce searching method is not only timeconsuming but also impractical due to extreme large of search space. To reduce the design complexity while maintaining the performance, we propose a bubblesort like method to generate the new interleaver candidate which is a swapped sequence from a baseline interleaver. The distance spectrum is used as the BER evaluation tool to select the best interleaver from a limited search space. Simulation results show that the proposed design method can improve the performance effectively for generic interleavers.