Patent ID: 8243646

Claim:
A method for selectively communicating through an infrastructure IP network with a group of computerized receiving stations according to their geographical status, said method comprising: dividing a geographical area into a plurality of geographical cells, each cell being a unique geographical region within the geographical area, each cell being associated with one and only one unique joining address of a plurality of joining addresses, a totality of joining addresses in a joining message consisting of the one and only one unique joining address to which each cell is associated, a receiving station located in one cell of the plurality of cells periodically transmitting a geographical message to a central station in accordance with a schedule, said geographical message being an IP unicast message comprising a current geographical status of the receiving station; in response to transmitting one geographical message of the periodically transmitted geographical messages, said receiving station receiving the joining message from the central station, said joining message being an IP unicast message comprising the plurality of joining addresses, each joining address being a unique multicast IP address associated with a corresponding multicast group related to the current geographical status; and after said receiving the joining message, said receiving station receiving all and only messages received at the joining addresses via a wireless infrastructure IP network.