Transitioning to a roadside unit state

1. A method performed by one or more processors, comprising:

receiving, at an interface of a vehicular device that is associated with the one or more processors, a notification message indicative of an occurrence of an event, wherein the interface is configured for communication with the one or more processors of the vehicular device;

determining that a position of the vehicular device is located on a boundary of a reachability area surrounding a source of the event, the boundary of the reachability area being the position of the vehicular device proximate to (i) one or more vehicular devices that are informed of the occurrence of the event and that are located inside of the reachability area, and (ii) one or more vehicular devices that are uninformed of the occurrence of the event and that are located outside of the reachability area;

determining that a direction of movement of the vehicular device is towards the source;

responsive to determining that the position is on the boundary of the reachability area and that the direction of movement of the vehicular device is towards the source, automatically controlling an operational state of the vehicular device for entering a roadside unit state in which the vehicular device acts a roadside unit for a pre-defined period of time;

detecting the one or more vehicular devices that are uninformed of the occurrence of the event and that are located outside of the reachability area; and

broadcasting the notification message to the one or more uninformed vehicular devices.

2. The method of claim 1 , further comprising:

receiving, from at least one of the one or more uninformed vehicular devices, information indicating receipt of the broadcast notification message.

3. The method of claim 1 , further comprising:

detecting an absence of receipt of information indicating that at least one of the one or more uninformed vehicular devices received the broadcast notification message.

4. The method of claim 1 , wherein entering the roadside unit state comprises causing movement of the vehicular device that is associated with the one or more processors to temporarily cease for re-broadcasting of the notification message.

5. The method of claim 1 , further comprising:

determining that the pre-defined period of time has elapsed;

responsive to determining that the pre-defined period of time has elapsed:

enabling movement of the vehicular device that is associated with the one or more processors; and

transitioning from the roadside unit state to another state for performing one or more of storing the notification message, carrying the notification message, and forwarding the notification message.

6. The method of claim 1 , wherein the vehicular device that is associated with the one or more processors comprises the one or more processors.

7. The method of claim 1 , wherein the notification message comprises one or more of traffic information, road information and safety information;

wherein the event comprises one or more of traffic related conditions, an accident, and road related conditions; and

wherein the source comprises one or more of a location of the traffic related conditions, a location of the accident, a vehicular device that caused the accident, and a location of the road related conditions.

8. The method of claim 1 , wherein determining that the position of the vehicular device that is associated with the one or more processors is located on the boundary of the reachability area surrounding the source of the event comprises:

determining, based on execution of a series of instructions, that the position of the vehicular device that is associated with the one or more processors is located on the boundary of the reachability area surrounding the source of the event;

wherein the series of instructions comprise:

∠(A, S, i)    angle between a vector (from Vehicle A to Vehicle S) and another vector (from

Vehicle A to Vehicle i) where ∠(A, S, i) ε [−π, π].

Nbr(A)    set of all neighboring vehicles of Vehicle A.

d A    moving direction of Vehicle A with respect to a line connecting from Vehicle A to

Vehicle S.

When A receives the message for the first time from Vehicle S

for all i ε Nbr(A)\ {S} do

 θ i    ∠(A, S, i)

end for

θ −     min (min i (θ i ), 0)

θ +    (max (max i (θ i ), 0)

if |θ + | + |θ − | < π and d A ε [θ − , θ + ] then

 A   temporary RSUs

end if

wherein vehicle A comprises the vehicular device that is associated with the one or more processors;

wherein vehicle S comprises one or more of the source and one of the one or more informed vehicular devices; and

wherein vehicle i comprises a neighbor of vehicle A.

9. The method of claim 1 , further comprising:

detecting a density of vehicular devices in proximity to the vehicular device associated with the one or more processors;

determining a size of the region of interest; and

determining the pre-defined period of time based on the size of the region of interest and based on the density of vehicular devices in proximity to the vehicular device associated with the one or more processors.

10. The method of claim 1 , further comprising:

indirectly detecting a rebroadcast of the notification message by at least one of the one or more uninformed vehicular devices to which the one or more processors originally broadcast the notification message, with indirect detection based on one or more of beacon messages and overhearing the notification message being broadcast by the at least one of the one or more uninformed vehicular devices; and

in response to detecting, transitioning from the roadside unit state to another state for performing one or more of storing the notification message, carrying the notification message, and forwarding the notification message.

11. One or more non-transitory machine-readable media configured to store instructions that are executable by one or more processors to perform operations comprising: receiving, at an interface of a vehicular device that is associated with the one or more processors, a notification message indicative of an occurrence of an event, wherein the interface is configured for communication with the one or more processors of the vehicular device; determining that a position of the vehicular device is located on a boundary of a reachability area surrounding a source of the event, the boundary of the reachability area being the position of the vehicular device proximate to (i) one or more vehicular devices that are informed of the occurrence of the event and that are located inside of the reachability area, and (ii) one or more vehicular devices that are uninformed of the occurrence of the event and that are located outside of the reachability area; determining that a direction of movement of the vehicular device is towards the source; responsive to determining that the position is on the boundary of the reachability area and that the direction of movement of the vehicular device is towards the source, automatically controlling an operational state of the vehicular device for entering a roadside unit state in which the vehicular device acts a roadside unit for a pre-defined period of time; detecting the one or more vehicular devices that are uninformed of the occurrence of the event and that are located outside of the reachability area; and broadcasting the notification message to the one or more uninformed vehicular devices.

12. The one or more non-transitory machine-readable media of claim 11 , wherein the operations further comprise: receiving, from at least one of the one or more uninformed vehicular devices, information indicating receipt of the broadcast notification message.

13. The one or more non-transitory machine-readable media of claim 11 , wherein the operations further comprise: detecting an absence of receipt of information indicating that at least one of the one or more uninformed vehicular devices received the broadcast notification message.

14. The one or more non-transitory machine-readable media of claim 11 , wherein entering the roadside unit state comprises causing movement of the vehicular device that is associated with the one or more processors to temporarily cease for re-broadcasting of the notification message.

15. The one or more non-transitory machine-readable media of claim 11 , wherein the operations further comprise: determining that the pre-defined period of time has elapsed; responsive to determining that the pre-defined period of time has elapsed: enabling movement of the vehicular device that is associated with the one or more processors; and transitioning from the roadside unit state to another state for performing one or more of storing the notification message, carrying the notification message, and forwarding the notification message.

16. The one or more non-transitory machine-readable media of claim 11 , wherein the vehicular device that is associated with the one or more processors comprises the one or more processors.

17. The one or more non-transitory machine-readable media of claim 11 , wherein the notification message comprises one or more of traffic information, road information and safety information; wherein the event comprises one or more of traffic related conditions, an accident, and road related conditions; and wherein the source comprises one or more of a location of the traffic related conditions, a location of the accident, a vehicular device that caused the accident, and a location of the road related conditions.

18. The one or more non-transitory machine-readable media of claim 11 , wherein determining that the position of the vehicular device that is associated with the one or more processors is located on the boundary of the reachability area surrounding the source of the event comprises: determining, based on execution of a series of instructions, that the position of the vehicular device that is associated with the one or more processors is located on the boundary of the reachability area surrounding the source of the event; wherein the series of instructions comprise:

∠(A, S, i) angle between a vector (from Vehicle A to Vehicle S) and another vector (from Vehicle A to Vehicle i) where ∠(A, S, i)ε{−π,π}

Nbr(A) set of all neighboring vehicles of Vehicle A

d A moving direction of Vehicle A with respect to a line connecting from Vehicle A to Vehicle S

When A receives the message for the first time from Vehicle S

for all iεNbr(A)\{S} do

θ i ∠(A, S, i)

end for

θ − min (min i (θ i ), 0)

θ + max (max i (θ i ), 0)

if |θ + |+|θ − |<π and d A ε[θ − , θ + ] then

A temporary RSUs

end if

wherein vehicle A comprises the vehicular device that is associated with the one or more processors; wherein vehicle S comprises one or more of the source and one of the one or more informed vehicular devices; and wherein vehicle i comprises a neighbor of vehicle A.

19. An electronic system comprising:

one or more processors; and

one or more machine-readable media configured to store instructions that are executable by the one or more processors to perform operations comprising:

receiving, at an interface of a vehicular device that is associated with the one or more processors, a notification message indicative of an occurrence of an event, wherein the interface is configured for communication with the one or more processors of the vehicular device;

determining that a position of the vehicular device is located on a boundary of a reachability area surrounding a source of the event, the boundary of the reachability area being the position of the vehicular device proximate to (i) one or more vehicular devices that are informed of the occurrence of the event and that are located inside of the reachability area, and (ii) one or more vehicular devices that are uninformed of the occurrence of the event and that are located outside of the reachability area;

determining that a direction of movement of the vehicular device is towards the source;

responsive to determining that the position is on the boundary of the reachability area and that the direction of movement of the vehicular device is towards the source, automatically controlling an operational state of the vehicular device for entering a roadside unit state in which the vehicular device acts a roadside unit for a pre-defined period of time;

detecting the one or more vehicular devices that are uninformed of the occurrence of the event and that are located outside of the reachability area; and

broadcasting the notification message to the one or more uninformed vehicular devices.

20. The electronic system of claim 19 , wherein the operations further comprise:

receiving, from at least one of the one or more uninformed vehicular devices, information indicating receipt of the broadcast notification message.