Patent ID: 7028076

Claim:
A system of apparatuses with a communication bus, the system comprising: at least two apparatuses, each comprising a circuit for transmitting messages; a plurality of bus connections, each connected between a respective pair of apparatuses; the apparatuses comprising circuits for organizing the system into a tree communication structure, in which a first one of the apparatuses is a root node and remaining apparatuses are subordinate nodes, communicating with the root node via the bus connections directly or via other subordinate nodes, the root node and the subordinate being allowed to arbitrate for access to the communication structure, the root node ultimately resolving arbitration; wherein the apparatuses are arranged to dynamically assign a second one of the apparatus to be root node; and wherein at least one of the apparatuses is arranged to select the second one of the apparatuses to become root node on the basis of detection that an apparatus other than the root node is expected to need relatively more access to the communication structure than other apparatuses, the second one of the apparatuses being selected closer to the apparatus needing relatively more access to the communication structure than the first one of the apparatuses, in terms of a number of connections needed to communicate from the first and second one of the apparatuses to the apparatus needing relatively more access to the communication structure.