Patent ID: 8767705
Filing Date: 2014-07-01
Classification: H04B,H04J,H04W

Abstract:
1. A method for synchronization and communication in a multi-hop network having a multiplicity of nodes and a central node, each of which having at least one transmitting/receiving unit, a storage unit and a processor unit, with communication between the transmitting/receiving units being based on wireless data transmission in frames, which are subdivided into defined slots, the nodes and the central node being spatially positioned in relation to each other in such a manner that at least one further node and/or the central node is located in the transmitting/receiving range of each node as its neighbor, communication between a node and the central node, if the node is located outside the central node's transmitting/receiving range, occurring through a utilization of further nodes as intermediate nodes via a multi-hop communication, and each node being assigned a hop count value giving the number of intermediate nodes raised by one for the respective node via which communication with the central node occurs, with the nearest intermediate node of the respective node in the network during communication with the central node being referred to as the node's predecessor, the node being a successor of the intermediate node, and all the nodes with the same hop count values being referred to as a layer, comprising the following process steps: a) transmitting a synchronization signal by a transmitting node to a first node, the synchronization signal comprising a beacon located in a beacon slot and at least the hop count value of the transmitting node, the beacon slot and hop count value being transmitted in the frame of the synchronization signal, the transmitting node being a central node or a previously synchronized node, the beacon slot being selected by the transmitting node, and the beacon being a data packet that enables synchronization of at least the first node, wherein the respective beacon slots and the hop count values are transmitted in the frame of the synchronization signal or as a separate data signal by the transmitting node for all the previously synchronized neighbor nodes of the transmitting node known to the transmitting node, wherein each node determines before assigning a new beacon slot that the beacon slot is free for twice the radio range, the beacon slot being selected randomly by the respective node, and wherein the node checks to determine that: (1) no neighbor is transmitting its beacon on said beacon slot by tapping the slot; and (2) no neighbor of a neighbor is using said beacon slot; b) receiving the synchronization signal and the data transmitted in connection therewith by the first node lying in the transmitting/receiving range of the transmitting node, c) synchronizing the first node to the synchronization signal, d) detecting, by the first node, neighbors of the first node and the respective beacon slot assignment and hop count value of each neighbor, e) determining the predecessor of the first node in the network by the first node on the basis of a given criteria, f) storing, by the first node, the data received with the synchronization signal as well as data received in connection therewith and determined therefrom, and g) repeating steps a) to f) at least until synchronization of all the nodes.