Differential Encoding Strategies for Transmission over Fading Channels

Transmission over Rician fading channels with unknown carrier phase is considered. Differential encoding of APSK constellations at the transmitter and non–coherent demodulation without channel state information/ carrier phase estimate at the receiver are applied. In this paper, various differential encoding strategies suited for multiple symbol detection are presented and compared. In particular, the encoding of the amplitude is considered. Moreover, a method for diversity enhancement is introduced. Regarding channel capacity as an appropriate performance measure when powerful channel coding is applied we show that the proposed differential encoding strategies have advantages over usual differential encoding for transmission over fading channels. The results obtained by numerical simulations are in great accordance with the prediction from information theory.