A communications method for retransmission of at least one fragment of a lost or erroneous message from a terminal to a gateway over a communications network comprising a plurality of terminals, communicating over a demand assignment multiple access and comprising a control center allocating the communications resource to the terminals, comprises: detection, by the gateway, of fragments of lost or erroneous messages and, when at least one fragment is detected, notification via the gateway to the control center of the loss of at least one fragment; calculation, by the control center, of a second allocation plan taking into account a new transmission of the fragment; notification by the gateway to the terminal of the loss of the fragment and notification by the control center to the terminal of the second allocation plan; transmission by the terminal of the lost fragment according to the second allocation plan to the gateway.