Reduced complexity frequency estimator for burst transmission

In burst transmission, carrier recovery is a critical point for synchronization systems. With a feedforward carrier phase recovery algorithm, a small frequency offset can significantly increase the cycle slips rate and then the phase error variance. Hence, in order to obtain an accurate carrier phase estimation a precise frequency correction is required. For M-PSK modulated signals an unbiased feedforward reduced complexity frequency estimator (RCFE), operating in the non-data aided mode (NDA) is derived from the maximum likelihood (ML) principle. A compromise is realized between noise filtering and estimation slip probability by minimizing the estimator variance. It is optimized for operation at low signal to noise ratio and with short bursts. Its performance is compared to the ML estimator. The estimator is applied to all feedforward synchronization architecture with QPSK modulated signals. The global performance of the modem synchronization unit is presented.