Turbo codes with non-primitive component codes

Unlike previous work on turbo codes in which both the feedback and generator polynomials used in the component codes are limited to primitive polynomials, in this paper a comparison of primitive and non-primitive feedback and generator polynomials is given. Simulation results over the AWGN channel show that non-primitive polynomials can achieve better performance at very low SNR. On this basis we comment on the conditions under which non-primitive turbo-codes may give better results than those based on primitive polynomials.