Time delay influence on the performance of adaptive turbo coded modulation

In this paper, the method of data fitting is applied to obtaining the BER expression for turbo coded modulation, and a fitting mathematical model is proposed, which resolve the problem that there is no exact BER expression for turbo coded modulation in performance analysis. With the time delay consideration, the performance of BER of adaptive turbo coded modulation is analyzed and simulated. The results show that adaptive turbo coded modulation is very sensitive to time delay; and in order to assure the target BER requirement the total time delay should be less than 0.001/f_D.