EM-Based Inetrpretation of Iterative Symbol Synchrinization

This paper is contributed to present a fast symbol timing recovery algorithm which is proper for variable symbol rate, burst mode and linear demodulation of digital transmission. At the receiver side, digitally received data are completely unknown and there is a fractional uncertainty in symbol period. Moreover the carrier frequency and phase offset are considered as unknown parameters of the received corrupted signal by AWGN channel. Gardner Timing Error Detection (TED) algorithm for None-Data-Aided (NDA) delay estimation is exploited in an iterative fashion under the interpretation of Expectation Maximization (EM) algorithm. The proposed algorithm utilizes the spectral efficiency provided by NDA estimator and due to the perfect timing recovery in the presence of carrier offset, the probability of desired carrier synchronization in lowest sample rate, i.e. symbol rate is provided. It will be shown that the proposed timing recovery method is enabled to recover all symbols of a burst and is practically easy to implement. Also the performance results confirm the system’s proficiency.

کلیدواژه ها:

burst transmission ، TED ، timing recovery