Using Two Independent Channels with Gateway for FlexRay Static Segment Scheduling

TL;DR

This paper introduces a heuristic scheduling algorithm for FlexRay's dual-channel system, aiming to enhance bandwidth utilization in automotive communication by effectively assigning ECUs and scheduling signals across channels.

Contribution

It presents a novel heuristic that decomposes the scheduling problem into ECU-to-channel assignment and channel scheduling, accommodating various fault-tolerance configurations.

Findings

Algorithm effectively schedules signals in independent and fault-tolerant modes.

Schedule efficiency increases with higher fault-tolerant signal proportion.

Real and synthesized data evaluations validate the approach.

Abstract

The FlexRay bus is a communication standard used in the automotive industry. It offers a deterministic message transmission in the static segment following a time-triggered schedule. Even if its bandwidth is ten times higher than the bandwidth of CAN, its throughput limits are going to be reached in high-class car models soon. A solution that could postpone this problem is to use an efficient scheduling algorithm that exploits both channels of the FlexRay. The significant and often neglected feature that can theoretically double the bandwidth is the possibility to use two independent communication channels that can intercommunicate through the gateway. In this paper, we propose a heuristic algorithm that decomposes the scheduling problem to the ECU-to-channel assignment subproblem which decides which channel the ECUs (Electronic Control Units) should be connected to and the channel scheduling subproblem which creates static segment communication schedules for both channels. The algorithm is able to create a schedule for cases where channels are configured in the independent mode as well as in the fault-tolerant mode or in cases where just part of the signals are fault-tolerant. Finally, the algorithm is evaluated on real data and synthesized data, and the relation between the portion of fault-tolerant signals and the number of allocated slots is presented.