Method for dynamically adapting the capacity of a contention transmission channel using a predetermined access protocol, the channel being shared by a plurality of terminals (4, 6, 8) TE forming a first network and defining an uplink from the terminals (4, 6, 8) to a gateway GW of connection to a second network, the method comprises the following steps: - in a first step, fixing the value of an external loading desired as a nominal operating point of the channel, the actual external loading of the channel being equal to the current rate of new entrant terminals sending a respective burst of data on the channel; - in a second step, determining, with the aid of a mathematical model or of a simulation, a first upper threshold S H and a second lower threshold S L having a quantity Gr monotonically sensitive to an external loading of the contention channel, the upper and lower external loadings of the contention channel corresponding to the first upper threshold S H or second lower threshold S L, respectively, the sensitive quantity Gr depending on a first probability of receiving an empty burst Pe, or on a pair of the first probability Pe and of a second probability of successfully receiving a burst Ps, or on a third probability of a burst having undergone a collision Pc, and on the type and on parameters defining the contention access protocol; - in a third step, estimating continuously, over an observation window of predefined width and on the basis of measurements being received in the said observation window of the expected bursts, a first measured probability of receiving an empty expected burst Pe, or a pair of measured probabilities formed by the first measured probability Pe and a second measured probability of successfully receiving a burst Ps, or a third measured probability of a burst having undergone a collision Pc; - in a fourth step, determining the current measured sensitive quantity Gr as a function of the first measured probability Pe, or of the pair of measured probabilities Pe and Ps, or of the third measured probability Pc; - in a fifth decision-taking step, when a crossing of the first upper threshold S H by the current sensitive quantity takes place once or several consecutive times while moving further away from the value of the quantity corresponding to the nominal external loading, increasing the current capacity of the transmission channel by releasing additional communication resources and by informing the terminals through a return pathway of the new composition of the increased-capacity transmission channel; and/or when a crossing of the second lower threshold S L takes place by the current sensitive quantity once or several consecutive times while moving further away from the value of the quantity corresponding to the nominal external loading, decreasing the current capacity of the transmission channel by removing communication resources in terms of frequencies from among the transmission resources currently made available and by informing the terminals through the return pathway of the new composition of the decreased-capacity transmission channel. - in a first step, fixing the value of an external loading desired as a nominal operating point of the channel, the actual external loading of the channel being equal to the current rate of new entrant terminals sending a respective burst of data on the channel; - in a second step, determining, with the aid of a mathematical model or of a simulation, a first upper threshold S H and a second lower threshold S L having a quantity Gr monotonically sensitive to an external loading of the contention channel, the upper and lower external loadings of the contention channel corresponding to the first upper threshold S H or second lower threshold S L, respectively, the sensitive quantity Gr depending on a first probability of receiving an empty burst Pe, or on a pair of the first probability Pe and of a second probability of successfully receiving a burst Ps, or on a third probability of a burst having undergone a collision Pc, and on the type and on parameters defining the contention access protocol; - in a third step, estimating continuously, over an observation window of predefined width and on the basis of measurements being received in the said observation window of the expected bursts, a first measured probability of receiving an empty expected burst Pe, or a pair of measured probabilities formed by the first measured probability Pe and a second measured probability of successfully receiving a burst Ps, or a third measured probability of a burst having undergone a collision Pc; - in a fourth step, determining the current measured sensitive quantity Gr as a function of the first measured probability Pe, or of the pair of measured probabilities Pe and Ps, or of the third measured probability Pc; - in a fifth decision-taking step,