Study of low rate turbo codes: Performance comparison and improvement.

Abstract

This thesis investigates the performance and a possible area of improvement to the original low rate Turbo Codes in the region of low SNR, and studies some potential variants for addressing such weakness. The thesis begins with examining the design and performance of the current low rate Turbo Codes, i.e., with code rate equal to 1/3 and below, and then determining the code rate which yields optimum performance at low SNR. In particular, it attempts to demonstrate through simulations that for a power limited transmission and low SNR, rate 1/3 Turbo Codes generally achieve the best performance. Next, simulations are conducted to compare the performances of variants with the current rate 1/3 Turbo Codes. Finally, the thesis concludes with a formulation of some important characteristics that concatenated codes should have in order to outperform the current rate 1/3 Turbo Codes. (Abstract shortened by UMI.)