Differential amplitude phase shift keying (DAPSK) - a new modulation method for DTVB

In digital terrestrial video broadcasting (DTVB) applications the objective is to transmit a high data rate of 34.368 Mbit/s in a single radio channel (bandwidth of 7 or 8 MHz). In this paper the performance of a multicarrier transmission technique, the well-known orthogonal frequency division multiplexing (OFDM) method, is analysed and the system parameters for the DTVB application are considered. A multilevel differential modulation technique, the so-called differential amplitude and phase shift keying (64-DAPSK) is proposed, in which the phase and the amplitude are used simultaneously for differential modulation. A differential modulation technique does not require any explicit knowledge about the radio channel properties in the differential channel equalization process. In an OFDM/64-DAPSK receiver it is therefore not necessary to implement a channel estimation and a frequency-domain equalizer, which reduces the computation complexity. The performance of both modulation techniques has been analysed in the uncoded case referring to Gaussian and frequency-selective Rayleigh fading channels. The results are described.