2 research outputs found
Periodic Scheduling and Packing Problems
This paper is motivated by periodic data transmission in autonomous cars. We
considered periodic tasks (with different periods) on one or several machines.
After reviewing the literature on the subject, we managed to generalize a
result of Lukasiewicz et al. (i.e., the equivalence of periodic scheduling with
the power of two periods and special 2D bin packing) to harmonic periods.
Furthermore, we use quite old results by Coffman, Garey, and Johnson to get an
approximation algorithm
Using Two Independent Channels with Gateway for FlexRay Static Segment Scheduling
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