Digital carrier recovery with frequency offset in TDMA transmission

Time-division multiple-access (TDMA) data transmission is used in various radio communication systems. In TDMA systems, demodulation requires the estimation of some parameters. In the systems considered, the phase is acquired at the beginning of each burst, while clock and frequency are tracked from burst to burst. Two classical algorithms are considered for phase estimation: the feedforward structure proposed by Viterbi & Viterbi (1983), and feedback structures like decision-directed loops. Their acquisition and tracking performance are compared both for coded and uncoded M-ary phase-shift keying (MPSK) modulations. The feedforward structure may be very sensitive to frequency offsets; therefore, the performance of a digital frequency estimator is analyzed in detail. All the algorithms considered are easily implemented with digital hardware