Data-aided Acquisition Research Articles

Carrier synchronisation for multiple symbol Trellis‐coded CPFSK in burst‐mode transmission

A carrier synchronisation technique for multiple symbol Trellis-coded continuous phase frequency shift keying (MSTC-CPFSK) system in burst-mode transmission is proposed. For the synchronisation technique, a joint data-aided (DA) acquisition and phase-locked loop (PLL) tracking algorithm is presented. First, an all-zero sequence is utilised as a pilot for DA acquisition, where the modulated pilot waveform is a direct current (DC) signal, eliminating the operation of modulation removal; and then, a second-order PLL structure is introduced for tracking processing, and we make an analysis of the tracking performance by calculating the equivalent Cramer–Rao bound (ECRB) for the second-order PLL structure; subsequently, we extend the obtained result to any order PLL structures; moreover, the ECRB for the MSTC-CPFSK system is also derived through arithmetical calculation; finally, some numerical results are given to verify the performance of the authors presented synchronisation algorithm, and the simulations illustrate that their algorithm can improve the throughput compared with the classical DA-only algorithm.

Performance analysis of a joint estimator for timing, frequency, and phase with continuous‐phase modulation

Performance analysis is presented for the joint estimation of symbol timing, frequency offset, and phase offset with continuous-phase modulation. In this study, undesirable influences on parameters to be estimated, which arise from the inaccuracy of the already estimated parameters, are computed mathematically. Based on performance analysis, a conditional Cramer-Rao bound (CRB) is put forward, and a hypothesise is made that phase offset variance with frequency error present should match with the conditional CRB for any digital phase modulation. Moreover, the hypothesis is manifested by analysing the log-likelihood function in a more general mathematical manner. To alleviate the influences, a data-aided acquisition and phase-locked loop tracking algorithm is proposed. The results of Monte Carlo simulations are presented, showing good agreement with theoretical analysis. Simulation results also show that the proposed algorithm can improve performance in terms of phase error variance at the expense of a high signal-to-noise ratio threshold.