1. Outer loop power control method for wireless communications systems which based on a data signal ( 107 , 108 ) received, coming from a base station ( 102 , 103 ) or from a mobile station ( 104 ), comprises the following phases: establishing a target block error rate (BLER target ), calculating an estimate ( 701 ) of the desired signal to interference ratio (SIR rec ) and of some fading parameters in the channel ( 706 ) which characterize the signal ( 107 , 108 ) received, estimating some fading margins (M 1 , M 2 ,. .. , M N ) associated with some outage probabilities (p o1 , p o2 ,. .. , p oN ) and with the fading parameters in the channel ( 706 ), indicating the status of the data blocks ( 707 ) based on the checking of a Cyclic Redundancy Code (CRC), and establishing a target desired signal to interference ratio (SIR target ) for the outer loop, based on said status of the data blocks ( 707 ), the fading margins (M 1 , M 2 ,. .. , M N ) and the target block error (BLER target ) of the outer loop, by means of a dynamic adjusting function which performs a mapping between a quality criterion based on the outage probabilities (p o1 , p o2 ,. .. , p oN ) and the quality criterion based on the target block error rate (BLER target ), so that the power is adapted to the propagation conditions of the data signal ( 107 , 108 ).