Patent ID: 7443929

Claim:
A method for adaptive control of bandwidth of a carrier recovery loop in a radio transmission system, said system comprising a local oscillator and a phase locked loop (PLL) for tracking a carrier phase, the PLL having a transfer function, characterized in that a phase error in the PLL is adjusted to an optimum level by means of a loop filter incorporated in said PLL, said optimization of the phase error in the PLL comprising, at every symbol time, the steps of: determining a first value relative to phase noise in the local oscillator; estimating a second value relative to additive white Gaussian noise in the PLL; applying the said first and second values in a predetermined mathematical relationship representing the phase error variance σ e 2 as a function of a transfer function L(f) of said PLL, and as a function of said phase noise and of said additive Gaussian noise; and calculating a value of said PLL transfer function L(f) corresponding to an optimum phase error variance σ e 2 according to said predetermined mathematical relationship.