An Automotive Communication Bus Using OFDMA

Today’s automotive communication systems use baseband pulse modulation and time-division or carrier-sense multiple access. In future in-vehicle networks, more devices need to be connected in a multipoint-to-multipoint topology. We have developed a new automotive bus system based on orthogonal frequency division multiple access (OFDMA) enabling better channel adaptation and fine-granular multi-user access. We highlight the advantages of OFDMA in automotive and industrial applications, introduce our system concept and demonstrate its feasibility by means of a prototype. Finally, we discuss the use of electrical and optical media.

1. INTRODUCTION

Motorized vehicles involve numerous communication connections between Electronic Control Units (ECUs), sensors and actors today. Many ECUs need to communicate with each other [1]. This establishes a meshed in-vehicle network (IVN) with more than 100 devices in modern cars [2]. The number of nodes and average amount of data per node increased over time as vehicles became increasingly equipped with intelligent functions. This development is accelerating as the trend toward autonomous emerges. To reduce the increasing complexity, especially in the wiring harness, car manufacturers have recently introduced a new zonal architecture [3], which requires flexible high-speed multipoint-to-multipoint (MP2MP) links for backbone connectivity. Currently, switched Automotive Ethernet is used. Automotive Ethernet was adopted from conventional Ethernet, modified and completed for automotive demands e.g., by using single-pair full-duplex communication (integrated into [4] from IEEE Std 803.3bp/bw). Classical bus systems like LIN, CAN and FlexRay are used intra-zone and often bridged through the Ethernet backbone network when used in other zones.