Abstract: A method for communication between several nodes and a maste: in a communication network, wherein each node is assigned a time slot in which to transmit. The nodes are arranged in groups, so that the first group comprises all nodes inside the coverage area of the master. The second group is outside the coverage area of the master but inside the coverage area of any node of the first group, etc. Any node reaches the master or is being reached by the master via a node in a previous group in a multi-hop approach. The time slots are assigned in dependence of the distance to the master. In a message period, in which the master sends a message to any node, the first group is assigned a first group of time slots, and the second group is assigned a second group of time slots, following the first group of time slots, etc. In this way, the message from the master can be sent out to all nodes in a single message period.

Abstract: A security system (100) for use on a boat comprising a central unit (1), one or several personal units (2), repeaters (4) and relay boxes (5). Each component includes a radio module. The central unit (1) forms a master and the other components form nodes of a multi-hop network, which 10 wirelessly exchanges information between the components. A method for operating the security system is provided.