Channel estimation and compensation for preamble-assisted DAPSK transmission in digital mobile radio system

This paper presents a novel channel estimation and compensation technique, combining fading estimation and frequency offset estimation, for preamble-a ssisted differentially encoded amplitude- and phase-shift keying (DAPSK) tr ansmission in the digital mobile radio system. The received preamble symbol s are used to estimate the combined distortions caused by multipath fading and frequency offset. The detected data symbols as well as preamble symbols are used to enhance the accuracy of the estimation process. The combined d istortions can be compensated in the data symbols at the same time. The sto rage-delay time of the estimation process is only several symbols long. A s eries of computer simulations have been carried out to investigate the bit error rate performances of the preamble-assisted 16-DAPSK signals with unce rtain frequency offset in the frequency-nonselective and frequency-selectiv e Rayleigh fading channels.