Image Processing Reference
In-Depth Information
The COM component is generated off-line on the basis of the knowledge of the signals, the
I-PDUs,andtheallocationofapplicationsotwarecomponentsontheECUs.heAUTOSARPDU
Router (see Figure .), according to the configuration, dispatches each I-PDU to the right network
communication stack. his basic component is statically generated off-line as soon as the allocation of
software components and the operational architecture is known. Other basic software components of
the communication stack are responsible for the segmenting/reassembling of I-PDU(s) when needed
(FlexRay TP, CAN TP) or for providing an interface to the communication drivers (FlexRay Interface,
CAN Interface, LIN Interface).
13.4 Open Issues for Automotive Communication Systems
13.4.1 Optimized Networking Architectures
The traditional partitioning of the automotive application into several distinct functional domains
with their own characteristics and requirements is useful in mastering the complexity, but this leads
to the development of several independent subsystems with their specific architectures, networks,
and software technologies.
Some difficulties arise from this partitioning as more and more cross-domain data exchanges are
needed. his requires implementing gateways whose performances in terms of CPU load and impact
on data freshness have to be carefully assessed (see, for instance, Ref. []). For instance, an ECU
belonging, from a functional point of view, to a particular domain can be connected, for wiring rea-
sons, onto a network of another domain. For example, the diesel particulate filter (DPF) is connected
onto the body network in some vehicles even though it belongs, from a functional standpoint, to the
powertrain. his can raise performance problems as the DPF needs a stream of data with strong tem-
poral constraints coming from the engine controller located on the powertrain network. Numerous
other examples of cross-domain data exchanges can be cited such as the engine controller (power-
train) that takes input from the climate control (body) or information from the powertrain displayed
on the dashboard (body). here are also some functions that one can consider as being cross-domains
such as the immobilizer, which belongs both to the body and powertrain domains. Upcoming X-by-
Wire functions will also need very tight cooperation between the ECUs of the chassis, the powertrain,
and the body.
A current practice is to transfer data between different domains through a gateway usually called
the “central body electronic,” belonging to the body domain. his subsystem is recognized as being
critical in the vehicle: it constitutes a single point of failure, its design is overly complex and
performance problems arise due to an increasing workload.
An initial foreseeable domain of improvement is to further develop the technologies needed for the
interoperability between applications located on different subnetworks. With the AUTOSAR project,
significant progresses in the area of MW have been achieved over the last years and we are coming
closer to the desirable characteristics listed in Section ..
Future work should also be devoted to optimizing networking architectures. his implies rethink-
ing the current practice that consists of implementing networks on a per-domain basis. The use of
technologies that could fulfill several communication requirements (e.g., high-speed, event-triggered
and TT communication, all possible with FlexRay) with scalable performances is certainly one possi-
ble direction for facilitating the design. Certainly, software tools, such as our tool NETCAR-Analyzer
(seehttp://www.realtimeatwork.com),willbehelpfultomasterthecomplexityandcomeupwithcost
and dependability-optimized solutions. he use of software along the development cycle will be facil-
itated by the advent of the ASAM FIBEX standard [], in the process of being adopted by AUTOSAR,
which enables to fully describe the networks embedded in a vehicle (CAN, LIN, FlexRay, MOST, and
TTCAN protocols), the frames that are exchanged between ECUs and the gatewaying strategies.
