Differential encoding strategies for transmission over fading channels

Transmission over Rician fading channels with unknown carrier phase is cons idered. 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 e ncoding strategies suited for multiple symbol detection are presented and c ompared. In particular, the encoding of the amplitude is considered. Moreov er, a method for diversity enhancement is introduced. Regarding channel cap acity as an appropriate performance measure when powerful channel coding is applied we show that the proposed differential encoding strategies have ad vantages over usual differential encoding for transmission over fading chan nels. The results obtained by numerical simulations are in great accordance with the prediction from information theory.