Analysis of turbo codes with asymmetric modulation

Abstract

If different energies are assigned to two outputs of a turbo encoder, the information bit and parity bit, then the performance will be changed according to the ratio of the information bit energy to the parity bit energy. The optimum point of the ratio may not be 1. As the rate of the turbo code is changed, the optimum point will also be changed. Rate 1/2, 1/3, 1/4 and 1/5 turbo codes with asymmetric modulation are considered.