Patent ID: 8165170

Claim:
A method for accessing a medium by a transmit node in a synchronous communications network comprising a plurality of nodes capable of accessing said medium during access time slots of predetermined duration to transmit data frames via said network, said plurality of nodes comprising a master node that implements a clocking that defines a network cycle for accessing said medium and comprising at least two slave nodes being slaves of said clocking including said transmit node, each network cycle comprising a plurality of frames transmitted during said access time slots according to a predetermined transmission sequence, wherein the transmit node performs indirect synchronization with the master node for accessing said medium, the indirect synchronization comprising: receiving at least one frame coming from at least one of the other slave nodes of the network; from each frame received, obtaining synchronization information pertaining to a level of synchronization of the other slave node having sent said frame, said level of synchronization of the other slave node being relative to the master node; selecting a reference node from among the at least one of the other slave nodes from which at least one frame has been received, as a function of said synchronization information, the transmit node being indirectly synchronized with the master node via the reference node; determining a start of access time slot from the positions in said transmission sequence of the frames associated with the reference node and with said transmit node; and accessing said medium at said determined start of access time slot.