Reliable broadcast transmission in a vehicular environment

1. A method for reliable broadcast transmission by a moving driven vehicle comprising the steps of:

a) providing a local road map that changes dynamically, as the driven vehicle moves, according to transmissions of at least one other vehicle; and

b) using the local road map and a request to send/clear to send (RTS/CTS) handshake to reliably broadcast data to other vehicles in the vehicular environment.

2. The method of claim 1 , wherein the step of providing a local map includes creating the local road map incrementally at the driven vehicle.

3. The method of claim 1 , wherein the step of providing a local map includes obtaining the local road map from a navigation system.

4. The method of claim 1 further including the steps of:

c) determining a radio frequency (RF) coverage limit; and

d) using the RF coverage limit in conjunction with the local road map and the RTS/CTS handshake to reliably broadcast the data.

5. The method of claim 2 , wherein the creating a local map incrementally includes creating the local road map using GPS information received in a plurality of beacons transmitted by a respective plurality of vehicles, wherein each beacon is associated with a particular vehicle.

6. The method of claim 4 , wherein the step of determining a RF coverage limit includes learning the RF coverage limit iteratively.

7. The method of claim 1 , wherein the step of using the local road map and a RTS/CTS handshake includes:

i. determining a RTS/CTS area; and

ii. performing the RTS/CTS handshake with a pivot vehicle within the RTS/CTS area.

8. A method for reliable broadcast transmission in a vehicular environment comprising the steps of:

a) providing a dynamic local map, for a driven vehicle;

b) selecting a pivot vehicle;

c) performing a request to send/clear to send (RTS/CTS) handshake between the driven vehicle and the pivot vehicle to allow reliable broadcast of data by the driven vehicle to other vehicles in the vehicular environment; and

d) subsequent to said handshake, broadcasting the data by the driven vehicle to the other vehicles in the vehicular environment.

9. The method of claim 8 , wherein the step of selecting a pivot vehicle includes selecting the pivot vehicle based on the dynamic local map.

10. The method of claim 8 , wherein the step of selecting a pivot vehicle includes selecting the pivot vehicle based on the dynamic local map and on a radio frequency (RF) coverage limit.

11. The method of claim 8 , wherein the step of providing a dynamic local map includes creating the dynamic local map incrementally at the driven vehicle.

12. The method of claim 8 , wherein the step of providing a dynamic local map includes obtaining the dynamic local map from a navigation system.

13. The method of claim 11 , wherein the creating a dynamic local map incrementally includes creating the dynamic local map using GPS information received in a plurality of beacons transmitted by a respective plurality of vehicles, wherein each beacon is associated with a particular vehicle.

14. The method of claim 10 , wherein the RF coverage limit is learned iteratively by the driven vehicle.

15. The method of claim 8 , wherein the dynamic local map is a local road map that changes dynamically, as the driven vehicle moves, according to transmissions of at least one other vehicle.

16. The method of claim 8 , wherein the pivot vehicle is selected by the driven vehicle.

17. A system for reliable broadcast transmission in a vehicular environment that includes a plurality of vehicles, comprising:

a) driven vehicle;

b) means to provide, to the driven vehicle, a dynamic local map;

c) means for the driven vehicle to select a pivot vehicle based on the dynamic local map; and

d) means to perforin a request to send/clear to send (RTS/CTS) handshake between the driven vehicle and the pivot vehicle to allow reliable broadcast of data by the driven vehicle to other vehicles in the vehicular environment.