Turbo coded double differential phase shift keying in aeronautical channels

In this paper, we present the results of using a turbo decoder to retrieve a serially encoded data stream, which has been transmitted over an aeronautical channel. The transmitted data streams are Double Differential Phase Shift Keying (DDPSK) modulated signals, which are encoded using two rate one-half (1/2) recursive systematic convolutional (RSC) encoders, and then transmitted over the channel. The aeronautical channels are more affected by multipath fading and Doppler shift. The DDPSK modulation scheme is a differential modulation scheme and it can withstand Doppler shift [9]. Also the DDPSK modulation scheme does not require a carrier recovery circuit at the receiving end. The DDPSK can be extended to an n^th order differential PSK, i.e. DⁿPSK. Results show that the performance of the DDPSK signal can be increased by using Turbo code in aeronautical channels.