Method and device for carrier recovery using multiple sources

Abstract

A receiver comprises a multiple source phase estimator. The latter comprises a pilot-phase estimator, a data-driven average phase estimator, a selector and a common interpolation controller. The selector selects either the pilot-phase estimator or the data-driven average phase estimator as the source of determined phase estimates at particular times. At other times, the common interpolation controller provides interpolated phase estimates as a function of a linear interpolation based on a respective determined phase estimate.

Description

technical field [0001] The present invention relates generally to communication systems, and more particularly to carrier recovery. Background technique [0002] A carrier recovery loop or carrier tracking loop is a typical component of a communication system. The carrier recovery loop takes the form of a phase-locked loop (PLL), and generally a "Costas loop". The latter typically use a decision-oriented phase error estimator to drive the PLL. In a decision-directed phase error estimator, the loop is driven by the phase error between the received signal point and each sliced ​​symbol (nearest symbol) taken from the symbol constellation. In other words, for each received signal point, a hard decision is made as to which is the closest (and possibly correct) symbol (also called the clipped symbol) of the symbol constellation. Then, based on this hard decision, the PLL is driven using the phase error between the received signal point and the associated clipped symbol. When ...

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Problems solved by technology

[0003] However, as the signal-to-noise ratio (SNR) decreases, the hard decision process starts to make more and more wrong decisions related to the received symbols, so the phase error estimation method for the Costas loop described above becomes less and less reliable

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