The present invention relates to the field of contention in a network of communicating nodes. The present invention especially relates to a master node for a communication network, to a slave node device for a communication network, to a network comprising the master node device and at least one slave node device and to a method of contention in a network of nodes. The method of contention according to the present invention is method in a network comprising slave nodes, said slave nodes comprising a group of first slave nodes, the method comprising the step of sending, by every first slave node participating in a contention, a number of two or more contention participation messages during a contention window associated with the first slave node.