Method for broadcasting one or more signalling messages in a communication network comprising at least two clusters (10 1 , 10 2 ), each of the clusters comprising at least one cluster head (24 1 , 24 2 ) which is capable of administering communications and a plurality of nodes (11 1k , 11 2k ) which are provided with transmitting/receiving means , each of the clusters operating on a dedicated radio channel (CH 1 , CH 2 ), and all the clusters accessing a common channel CS, in which each cluster has a time slot of the common channel CS which is dedicated to the set of nodes which belong to the cluster, the method comprising at least the following steps: • at least the cluster head (24 1 ) of the first cluster (10 1 ) transmits the signalling message M towards a set of nodes (11 1k ) which are located in the cluster (10 1 ) thereof using the dedicated radio channel CH 1 thereof, • the nodes (11 1k ) of the first cluster (10 1 ), which have received and decoded the signalling message M, relay this signalling message M towards one or more relay nodes (11 jk ) which belong to other clusters of the network which are in radio range using a cooperative coherent transmission mechanism which is distributed over the time slot of the common channel CS which is dedicated to the first cluster in the following manner: the cluster head (24 1 ) selects one or more nodes (11 1k ) in order to reach the adjacent clusters, • if two nodes (11 1k ) selected do not share external proximity, they transmit on the same time slot, without interfering with each other, • if two nodes (11 1k ) selected have in common a portion of the external proximities thereof, they use the same time slot in a cooperative manner in order to improve the quality of the transmission thereof, • the relay node(s) (11 jk ) of the other clusters (10 j ), which have received and decoded the signalling message M, transmit it to the cluster head (24 j ) thereof using a distributed cooperative transmission method on the dedicated channel (CH j ) thereof. • at least the cluster head (24 1 ) of the first cluster (10 1 ) transmits the signalling message M towards a set of nodes (11 1k ) which are located in the cluster (10 1 ) thereof using the dedicated radio channel CH 1 thereof, • the nodes (11 1k ) of the first cluster (10 1 ), which have received and decoded the signalling message M, relay this signalling message M towards one or more relay nodes (11 jk ) which belong to other clusters of the network which are in radio range using a cooperative coherent transmission mechanism which is distributed over the time slot of the common channel CS which is dedicated to the first cluster in the following manner: the cluster head (24 1 ) selects one or more nodes (11 1k ) in order to reach the adjacent clusters, • if two nodes (11 1k ) selected do not share external proximity, they transmit on the same time slot, without interfering with each other, • if two nodes (11 1k ) selected have in common a portion of the external proximities thereof, they use the same time slot in a cooperative manner in order to improve the quality of the transmission thereof, • if two nodes (11 1k ) selected do not share external proximity, they transmit on the same time slot, without interfering with each other, • if two nodes (11 1k ) selected have in common a portion of the external proximities thereof, they use the same time slot in a cooperative manner in order to improve the quality of the transmission thereof, • the relay node(s) (11 jk ) of the other clusters (10 j ), which have received and decoded the signalling message M, transmit it to the cluster head (24 j ) thereof using a distributed cooperative transmission method on the dedicated channel (CH j ) thereof. <EOS>