The article intends to make a succinct compilation of the advances made in the control of medium access in cognitive radio systems, in addition to presenting a classification system of secondary cognitive users based on the classification of SUs with FAHP, in order for the allocation of resources in the stage of spectral sharing of cognitive radio networks to be fairer or more equitable.To estimate the level of performance for the "equitability" metric, several simulations were performed and the behavior of the following metrics was evaluated: admission efficiency, efficiency of amount of information sent, energy efficiency and total efficiency.