Performance analysis of extended OQPSK carrier phase recovery algorithm in satellite channel

This paper proposes a new extended decision-directed decision-estimated phase recovery algorithm based on maximum likelihood parameter estimation for OQPSK (offset QPSK). In this scheme, compared to the conventional one, the data dependent noise of the phase recovery loop is reduced by inserting a filter with 2 taps to the in-phase and quadrature channel respectively before the phase detector. The proposed scheme is compared to the conventional QPSK scheme with respect to BER (bit error rate) and phase error for roll-off factors of the baseband filter, output backoffs of the nonlinear satellite channel and loop bandwidth.