Phase Estimation Algorithm for SFH/PSK Signals Using Few Reference Symbols

In military satellite communication systems that use frequency hopped waveforms, many systems use differential phase modulations. However, the use of DPSK over PSK results in reduced performance. To estimate the phase of each hop by using both few reference symbols and information symbols in a hop, BPSK and DPSK modulated signals can achieve higher performance. This paper focuses on QPSK and DQPSK waveforms where phase estimator is applied. The performance of the 4-ary modulated signals was evaluated for the case of additive white Gaussian noise (AWGN) and Rayleigh fading channels. Within given SNR range, depending on the environment and modulation used, performance gains of up to 3 dB were realized for 2-ary modulated signals. Only under AWGN channel, 4-ary modulated signals can result higher performance than noncoherent detection.