Carrier frequency recovery uses punctured four-phase modulation-demodulation for accurate signal recovery

摘要

The method includes replacing certain symbols transmitted in MDP-X symbols with MDP-2(BPSK) symbols which, associated with the preamble of the packet, are used for carrier frequency recovery. The method includes replacing certain symbols transmitted in MDP-X symbols with MDP-2(BPSK) symbols which, associated with the preamble of the packet, are used for carrier frequency recovery. This modulation symbol puncturing can be carried out, or not, on the transmitted bits. In cases where the transmitted bits are punctured simultaneously with the modulation symbols, the efficiency remains unchanged (same number of bits transmitted per Hertz). Degradation ensues in a transmission with convolutional coding which depends on the proportion of punctured symbols, but this remains very low - typically 1/10 of dB.