On Burst-Mode Synchronization of SOQPSK

In this paper, we present a maximum likelihood synchronization algorithm which jointly estimates frequency offset, symbol timing and carrier phase for shaped-offset quadrature phase-shift keying (SOQPSK) signals. We have considered a burst-mode transmission scenario in which a known and optimized training sequence is embedded in the beginning of each burst for the purpose of data-aided (DA) synchronization in a feedforward structure. The proposed algorithm first estimates the frequency offset independently from other parameters. The estimated frequency is then used to derive the symbol timing which is followed by the carrier phase estimation. The mean-squared error (MSE) of the proposed algorithm is computed via simulations. The results show that the proposed algorithm performs near the theoretical Cramer-Rao bound (CRB) at signal-to-noise ratios (SNRs) as low as 0 dB.