Abstract
Data networks are naturally prone to interferences that can corrupt messages, leading to performance degradation or even to critical failure of the corresponding distributed system. To improve resilience of critical systems, time-triggered networks are frequently used, based on communication schedules defined at design-time. These networks offer prompt error detection, but slow error recovery that can only be compensated with bandwidth overprovisioning. On the contrary, the Flexible Time-Triggered (FTT) paradigm uses online traffic scheduling, which enables a compromise between error detection and recovery that can achieve timely recovery with a fraction of the needed bandwidth. This article presents a new method to recover transmission errors in a time-triggered Controller Area Network (CAN) network, based on the Flexible Time-Triggered paradigm, namely FTT-CAN. The method is based on using a server (traffic shaper) to regulate the retransmission of corrupted or omitted messages. We show how to design the server to simultaneously: (1) meet a predefined reliability goal, when considering worst case error recovery scenarios bounded probabilistically by a Poisson process that models the fault arrival rate; and, (2) limit the direct and indirect interference in the message set, preserving overall system schedulability. Extensive simulations with multiple scenarios, based on practical and randomly generated systems, show a reduction of two orders of magnitude in the average bandwidth taken by the proposed error recovery mechanism, when compared with traditional approaches available in the literature based on adding extra pre-defined transmission slots.
Highlights
Today, a myriad of systems that are used directly or indirectly in our daily lives, e.g., cars, planes, and medical equipment, are controlled by distributed computing systems composed of sets of nodes that communicate with each other using communication networks to fulfill their global objectives.One network technology that is widely used to support short data exchanges is the Controller AreaNetwork (CAN) [1], with more than 700 million controllers sold every year [2]
The Controller Area Network (CAN) bit rate is 1 Mbps and LEC was set to 2.5 ms, corresponding to half of the period of the fastest messages, to allow time for their retransmission
Transmission errors are unavoidable and a method to guarantee the delivery of messages, despite error occurrence, is necessary
Summary
A myriad of systems that are used directly or indirectly in our daily lives, e.g., cars, planes, and medical equipment, are controlled by distributed computing systems composed of sets of nodes that communicate with each other using communication networks to fulfill their global objectives.One network technology that is widely used to support short data exchanges is the Controller AreaNetwork (CAN) [1], with more than 700 million controllers sold every year [2]. In TT systems, all activities, including message transmissions, are triggered in precise time instants to avoid contention in the access to shared resources, notably the bus This approach has been typically implemented in a static way, where the messages’ schedule is obtained offline and saved in a table with the triggering instants [8]. Access (TDMA) medium access mechanism, in which time is divided in slots that are exclusively and statically allocated to nodes, and within which predetermined messages are transmitted This bandwidth allocation method grants these systems a predictable and steady behavior under any operational scenario, which is an important characteristic for the certification of safety-critical systems, e.g., X-by-wire systems [14]. Static TDMA systems that need high reliability require the transmission of several message instances that most of the times are useless
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
