Method and device for carrier recovery using phase interpolation with assist

Abstract

In a receiver, a decision-directed phase estimator is used in conjunction with an interpolator to provide a phase estimate for use in carrier recovery. For example, a receiver comprises a pilot phase estimator, a Costas loop and an interpolation controller. The pilot phase estimator provides determined phase estimates at the pilot times and the interpolation controller provides interpolated phase estimates at other times as a function of a linear interpolation based on a respective determined phase estimate and at least one decision-directed phase error estimate from the Costas loop.

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. A carrier recovery loop is a form of a phase locked loop (PLL), usually in the form of a "Costas loop". The latter typically uses a decision-directed 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 the respective sliced ​​symbol (nearest symbol) from the symbol constellation. In other words, for each received signal point, a hard decision is made as to which is the closest (presumably correct) symbol (also called restricted symbol) in the symbol constellation. With this hard decision, the phase error between the received signal point and the associated barred symbol is then used to drive the PLL. Whe...

AI Technical Summary

Problems solved by technology

[0004] Unfortunately, in "interpolated carrier recovery", the linear interpolation process itself can present some problems if there are large frequency offsets, or phase noise, or definite phase estimates occur frequently (from pilot symbols or data result of driving average)

Images