2 Overhead & channel use for multiple messages. Unused elements in common message set. Security? A new message for each new application? Where to change a definition? Computation/Memory?

3 The Message Dispatcher is an interface between multiple safety applications and the lower-layer communication stack. The Message Dispatcher’s responsibility is to coordinate all the data exchange requirements of the applications running on a vehicle. Improve channel utilization by recognizing similarities in transmitted data.

4 Safety applications will register or send data elements to be broadcast to the MD. In some implementations the MD might collect data from other data sources within the vehicle. Message Dispatcher concept was recently contributed to the Society of Automotive Engineers (SAE) and has become an underlying principle in their safety message standardization process. The message dispatcher design can be divided into two broad topics.

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7 On an average day in the US, vehicular collisions kill 116 people and injure 7,900. In particular, Toyota actively participates in several consortiums that explore safety applications and related technologies, they working on two promising vehicular-safety applications: the Emergency Brake Warning (EBW) and Intersection Violation Warning (IVW) applications. These two safety applications, as well as others under consideration, demonstrate the potential of pervasive information in reducing vehicle collisions.

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11 The Emergency Brake Warning (EBW) application alerts the driver when a preceding vehicle performs a severe braking. The vehicle can then take appropriate action. The path history is only used when a severe-braking event occurs.

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16 More specifically, each vehicle running EBW broadcasts a heart-beat message at 3 Hz. Each HBM contains the vehicle’s current position, speed, direction, acceleration, and brake-applied status. Each HBM represents these values with short, minimally precise representations, which minimizes channel loading. A vehicle (say, vehicle 1, or the EBW sender) that is braking above a deceleration threshold sends an EBW message at 5 Hz. A vehicle that receives the EBW message (such as vehicle 3, or the EBW receiver) must determine if the sender is “relevant” and only warn its driver if the EBW sender lies in the forward path of the EBW receiver (using a proprietary algorithm that uses the bread crumbs of the EBW sender).

17 The Intersection Violation Warning (IVW) application warns the driver if violating a red light seems imminent. Many of the required data elements are similar to the EBW application. Vehicles then determine if a signal violation is imminent.

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19 With the IVW application, a road-side unit, colocated at a traffic-light intersection, will broadcast 3Hz information regarding the traffic light, including its location, light status, time until color change, intersection dimensions, and so forth. A vehicle (such as vehicle A) approaching the intersection will use its state to predict a 4 second trajectory. Vehicle A compares its predicted trajectory to determine if it will likely be in the intersection during a red light. If so, the driver of the potentially violating vehicle is alerted. In addition, the violating vehicle broadcasts a message with its speed, direction, and so forth, indicating the likely violation.

20 Define each element using: Data Frames: Combine frequently associated elements.

21 The driver has been alerted to a potential violation and is braking sharply. The message dispatcher combines the required data frames and data elements into a minimal set of messages Since the applications have registered data at different frequencies, the MD constructs three different messages: 1. Msg10Hz 2. Msg5Hz 3. Msg3Hz

22 Message Dispatcher composes messages and orchestrates sending

23 how the Message Dispatcher send and receive the data segments Demonstrated two method of application and how they work how the Message Dispatcher summarize data to minimize redundancy while sending messages. how the Message Dispatcher handles cases with many massages needed to be transmitted with different times.

24 Thanks for Listening…