Design and Enhancement of Bandwidth and Performance of Rate-1/2 Puncturing Based Turbo Convolution Codes using Simulink

It has been observed that particular rate-1/2 turbo code can achieve a lower error floor than that of their rate-1/3 parent codes. Nevertheless, good puncturing patterns can only be identified by means of an exhaustive search, whilst convergence towards low bit error probabilities can be problematic when the systematic output of a rate-1/2 turbo code is heavily punctured. In this paper, we present and study a family of rate-1/2 turbo code. We evaluate their bit error rate performance and we show that they always yield a lower error floor than that of their rate-1/3 parent codes. Furthermore, we compare analytic results to simulations and we demonstrate that their performance converges towards the error floor region, owning to the QPSK modulation technique as compared to the un-modulated one. Consequently, we propose punctured modulated turbo code as a means of improving the bandwidth efficiency and simultaneously lowering its error floor. The investigations are carried out for transmission on additive white Gaussian noise channels. For our simulation size of interleaver selected is 1024*1024 and keeping the number of iteration between 5to8. Simulations are conducted on MATLAB at maximum SNR range of 7 dB. In addition we also simulate the performance of punctured turbo codes with increasing the number of iteration and its effect on the performance is analyzed.