An adaptive data reduction protocol for future in-vehicle networks.

摘要

The demand for drive-by-wire, pre-crash warnings, telematics and many new features will require very high bandwidth from future in-vehicle networks. One straightforward solution to satisfy the bandwidth requirements of future vehicle networks would be to use a higher bandwidth bus or to use multiple busses. However, the use of a higher bandwidth bus would increase the cost of the network. Similarly, the use of multiple busses would increase the cost and the complexity of the wiring. Hence, neither option is viable solution for satisfying the requirements of high bandwidth. Another option would be the development of a higher layer protocol to reduce the amount of data to be transferred. The higher layer protocol could be acceptable provided it does not increase the message latencies for real time safety-critical applications. The cost of the protocol will be marginal since it will require minor changes in the software and no additional hardware. The amount of data can be reduced in various ways. For example, when cruise control of the vehicle is activated, the vehicle speed will be almost the same from one time instant to another time instant. Thus, the electronic control module responsible for sending the vehicle speed can send only one bit instead of the actual speed to inform the recipients that the speed did not change. Similarly, when the change in speed is very small, the electronic control module can send only the amount of change using only a few bits rather than the actual speed using many bits. The protocol can also be made adaptive by allowing it to select different message formats for different conditions of the vehicle. For example, when the vehicle is in the idle state, the message format can be different from the format when it is moving at 60 mph or higher. This work explains the adaptive data reduction protocol in detail and compares its performance with that of a nonadaptive protocol.