In-Vehicle Network Architecture for the Next-Generation Vehicles

The demand for drive-by-wire, telematics, entertainment, multimedia, pre-crash warning, remote diagnostic and software update, etc. will significantly increase the complexity of the future in-vehicle communication networks. New types of communication networks will also be necessary to satisfy the requirements of safety and fuel efficiency, and meet the demand for new features. Different sets of vehicle electronic modules will require different types of networks. For example, drive-by-wire and active collision avoidance systems need fault tolerant networks with time-triggered protocols, to guarantee deterministic latencies; multimedia systems need networks with high bandwidth to transfer video files; and body control electronics need low-bandwidth networks to keep the cost down. As the size and complexity of these networks increase, ease of integration has become a major challenge for design engineers. In today's vehicles, there are mainly two networks: a high-speed network for the power train and a low-speed network for the body electronics. Since the complexity of the network is increasing and the demand for bandwidth is growing, future vehicles will require many partitioned networks. The partitioning of the networks will be done based on the locality as well as the functionality of the modules. One of the challenging issues will be the selection of topology to interconnect various in-vehicle partitions of the network. Interconnection among all in-vehicle partitions of the network is necessary for diagnostics and software updates in various modules. One logical approach for interconnecting various partitions of the network would be via a hierarchical bus. This paper shows various types of hierarchical connections among the partitions of in-vehicle networks. Different partitions may use different protocols. For example, one partition may use the CAN protocol, the second partition may use the TTCAN protocol, the third partition may use the LIN protocol, and so on. The hierarchical bus will be using intelligent switches to facilitate the translation of messages from one protocol to another protocol while the messages will be moving from one partition to another partition. This paper discusses the advantages and disadvantages of various types of hierarchical connections in terms of cost, bandwidth, latency, fault tolerance, and many other features. The paper also presents simulation models that can be used to determine the performance of various types of partitions and network topologies.