Optimal scheduling of switched FlexRay networks

Schenkelaars, Thijs; Vermeulen, Bart; Goossens, Kees

doi:10.1109/date.2011.5763150

Cited by 13 publications

(11 citation statements)

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“…Some people even proposed and verified a holistic method (HOSA) to maximize the static slot usage by pilfering the unused static part for dynamic messages [18]. Besides the aforementioned methods, which increase network usage mostly via reducing wasted bandwidth at a given static slot length, 'FlexRay Switch' in [19] has expanded transmission efficiency by enabling different messages transmitting in the same slot through multiplexing and branch parallelism mechanisms, albeit subjected to the topology of the network.…”

Section: A Flexray Transmission Capabilitiesmentioning

confidence: 99%

A qualitative comparison of FlexRay and Ethernet in vehicle networks

Zeng

Khalid

Chowdhury

2015

2015 IEEE 28th Canadian Conference on Electrical and Computer Engineering (CCECE)

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This paper presents a qualitative study of FlexRay and Ethernet in in-vehicle communication networks. Although both protocols have experienced fast growth in the past years, they still have some important deficiencies that deserve attention. This qualitative study has not only outlined the important shortcomings of in-vehicle FlexRay and Ethernet, but also identified their unique competitive edges, respectively. Intensive analyses of both protocols are carried out from three key perspectives: system cost, data transmission capacity and fault detection capability. Some improving approaches have also been pointed out. It is revealed that at the current stage FlexRay is better than Ethernet in transmitting time critical signals deterministically, but has higher cost and complexity. Ethernet, though less deterministic than FlexRay, possesses much greater bandwidth and can transmit data at quite small latency and jitter. This qualitative study has indicated that both protocols need further improvement to meet the requirements of future in-vehicle networks, yet Ethernet may lead the development and expand faster. I. INTRODUCTIONEncoded communication channels have long been used to transmit signals among different controllers in in-vehicle networks. The typical motivations for this fact are: 1) To reduce cable cost. Since wire harness subsystem is the third most expensive and heaviest subsystem after engine and chassis [1], adopting coded communication is obviously a wise strategy to follow. 2) To save package space. As vehicles are built smaller in size but more enriched in functions, routing of wire harness has become increasingly challenging. 3) To cater the demands for higher bandwidth. Nowadays some luxury cars, even not fully featured, already have more than 70 ECUs and 2500 signals to transmit [2], letting alone accommodating the rising demands from ADAS and infotainment systems. 4) To enhance communication safety. Digital transmission has unparalleled advantages in resisting external disturbance over traditional point-to-point analog wires. Moreover, digital signals can be encrypted to further enhance data security in transmission.After LIN (Local Interconnect Network) and CAN (Controller Area Network), FlexRay and Ethernet are two most recently developed wired in-vehicle communication networks. FlexRay was firstly public released in 2004 and has gradually become an ISO standard after 2009. FlexRay is commonly understood as the protocol for X-by-Wire applications, and can provide deterministic communication for chassis and vehicle dynamic controls. BMW is the first

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Section: A Flexray Transmission Capabilitiesmentioning

confidence: 99%

A qualitative comparison of FlexRay and Ethernet in vehicle networks

Zeng

Khalid

Chowdhury

2015

2015 IEEE 28th Canadian Conference on Electrical and Computer Engineering (CCECE)

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“…In this paper, our goal is to schedule the messages with precedence relations in the SS. As in [2] we assume that slot multiplexing is used to increase the utilization of the FlexRay bus by definining a base-cycle (initial cycle) and repetition rate (transmission period) for each message. That is i.e., the same Frame Identifiers (Frame ID) can be assigned to more than one nodes only if they use in different CCs.…”

Section: Introductionmentioning

confidence: 99%

Message scheduling on static segment of FlexRay networks

Darbandi

Duong

Kim

2013

Third International Conference on Innovative Computing Technology (INTECH 2013)

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FlexRay is a hybrid in-vehicle communication protocol whichcarries out the transmission of time-triggered data in the static segment as well as event-triggered data in the dynamic segment. In this paper, we study the problem of scheduling static messages with precedence relations in FlexRay protocol. Our objective is to obtain the minimum number of used slots. To this end, a scheme for transformation of the precedence constrained message scheduling problem to a Strip Packing Problem is proposed. In thisproblem a set of rectangles must be placed within a strip. The goal is to place the rectanglesso that they do not overlap and so that the height ofthe area covered by rectangles is minimized. However, since Strip Packing Problem cannot solely deal with flexray specifications and precedence relations between items we introduce new constraints called FlexRay Constraints. We elaborate on a Linear Integer Programming that obtains the optimal solution. We study our approach based on a case study involving someadvanced automotive control applications.

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“…The switch architecture allows exploitation of branch parallelism, whereby the switch will repeat frames only on branches that contain the intended recipient [8]. This allows the same slots to be used simultaneously by multiple nodes in the same cycle and the intelligent FlexRay switch schedules the branch to which information has to be relayed [9].…”

Section: A the Flexray Protocolmentioning

confidence: 99%

Extensible FlexRay Communication Controller for FPGA-Based Automotive Systems

Shreejith¹,

Fahmy

2015

IEEE Trans. Veh. Technol.

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warwick.ac.uk/lib-publications Copyright and reuse:The Warwick Research Archive Portal (WRAP) makes this work by researchers of the University of Warwick available open access under the following conditions. Copyright © and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable the material made available in WRAP has been checked for eligibility before being made available.Copies of full items can be used for personal research or study, educational, or not-for profit purposes without prior permission or charge. Provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way.Publisher's statement: © 2015 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting /republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. A note on versions:The version presented here may differ from the published version or, version of record, if you wish to cite this item you are advised to consult the publisher's version. Please see the 'permanent WRAP url' above for details on accessing the published version and note that access may require a subscription. This paper describes an FPGA-based communication controller which features configurable extensions to provide functionality that is unavailable with standard implementations or off the shelf devices. It is implemented and verified on a Xilinx Spartan 6 FPGA, integrated with both a logic-based hardware ECU and a fully fledged processor-based ECU. Results show that the platform-centric implementation generates a highly efficient core in terms of power, performance and resource utilisation. We demonstrate that the flexible extensions help enable advanced applications that integrate features like fault-tolerance, timeliness and security, with practical case studies. This tight integration between the controller, computational functions and flexible extensions on the controller enables enhancements that open the door for exciting applications in future vehicles.Index Terms-Field programmable gate arrays; automotive systems; networks. I. INTRODUCTIONModern high-end vehicles incorporate one hundred or more embedded computing units which implement advanced capabilities like auto-park, pedestrian detection with auto-brake and other safety or comfort features. These algorithms perform complex processing on data gathered from a network of sensors, to produce control sequences for distributed actuators. The communication bandwidth and quality of service required for such advanced electronic control units (ECUs) exceeds the capabilities of the event-triggered Controller Area Network (CAN) protocol, that has ...

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Optimal scheduling of switched FlexRay networks

Cited by 13 publications

References 10 publications

A qualitative comparison of FlexRay and Ethernet in vehicle networks

A qualitative comparison of FlexRay and Ethernet in vehicle networks

Message scheduling on static segment of FlexRay networks

Extensible FlexRay Communication Controller for FPGA-Based Automotive Systems

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