Communication with receiving stations according to their geographical status

1. A method for communicating with a receiving station, 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, said joining message being an IP unicast message comprising the plurality of joining addresses; and

said receiving station receiving the joining message from a central station, said receiving station located in one cell of the plurality of cells.

2. The method claim 1 , each joining address being a unique multicast IP address associated with a corresponding multicast group related to a current geographical status of the receiving station.

3. The method claim 1 , said method further comprising:

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.

4. The method claim 1 , said method further comprising:

said receiving station periodically transmitting a geographical message to the central station in accordance with a schedule, said geographical message being an IP unicast message comprising the current geographical status of the receiving station, said receiving the joining message being in response to transmitting one geographical message of the periodically transmitted geographical messages.

5. The method of claim 4 , wherein the receiving station comprises a moving vehicle.

6. The method of claim 5 , wherein the geographical message comprises an identification of the vehicle and a current direction in which the vehicle is moving.

7. The method of claim 5 , wherein the schedule is dependent upon a speed characteristic of the vehicle.

8. The method of claim 5 , wherein the schedule is dependent upon a distance travelled by the vehicle.

9. The method of claim 5 , wherein the current geographical status is a geographical destination of the vehicle.

10. The method of claim 5 , wherein the current geographical status is a geographical origin of the vehicle.

11. A system, comprising a receiving station configured to implement a method for communicating with a receiving station, 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, said joining message being an IP unicast message comprising the plurality of joining addresses; and

said receiving station receiving the joining message from a central station, said receiving station located in one cell of the plurality of cells.

12. The system of claim 11 , each joining address being a unique multicast IP address associated with a corresponding multicast group related to a current geographical status of the receiving station.

13. The system of claim 11 , said method further comprising:

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.

14. The system of claim 11 , said method further comprising:

said receiving station periodically transmitting a geographical message to the central station in accordance with a schedule, said geographical message being an IP unicast message comprising the current geographical status of the receiving station, said receiving the joining message being in response to transmitting one geographical message of the periodically transmitted geographical messages.

15. The system of claim 14 , wherein the receiving station comprises a moving vehicle.

16. The system of claim 15 , wherein the geographical message comprises an identification of the vehicle and a current direction in which the vehicle is moving.

17. The system of claim 15 , wherein the schedule is dependent upon a speed characteristic of the vehicle.

18. The system of claim 5 , wherein the schedule is dependent upon a distance travelled by the vehicle.

19. The system of claim 15 , wherein the current geographical status is a geographical destination of the vehicle.

20. The system of claim 15 , wherein the current geographical status is a geographical origin of the vehicle.