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MPC-WORKSHOP JULI 2012
Fig. 8: Vehicle as a complex sensor/actuator node.
are distinguished on the E/E architecture toplevel,
backbone architecture, centralized architecture and
front/rear architecture (see Fig. 7). The larger blocks
represent domain gateways which route information
between the different bus segments that are existent in
the overall E/E architecture. In the case of a centralized
architecture only a single gateway is available
that connects all bus segments. The central gateway
approach has the advantage of information from all
bus segments being directly accessible within a single
control unit without additional latency, introduced e.g.
by a backbone connection. As described below, this
kind of topology is advantageous when opening the
internal vehicular network to an outer Vehicular Ad
hoc NETwork (VANET).
D. E/E Architecture Design for V2XC
Vehicle-to-X Communication (V2XC) based on a
VANET forms the next major step for extending the
automotive domain towards smart mobility. V2XC
promises improvements in situation awareness, traffic
management and active safety based on disseminated
information. A VANET is a highly dynamic sensoractuator-network
with vehicles as nodes. Depending
on the density of equipped vehicles, a varying number
of geologically distributed VANETs may merge or
separate depending on the participant’s movements.
Up to now, most research in the V2XC domain ends
up in describing protocols, application analysis and
standardization. Only limited effort is put into realization
and system architecture aspects. However, considering
vehicles as a simple network node while
neglecting the fact of up to around 100 devices communicating
inside which cause highly diverse internal
latency times and throughout rates, is not enough for
getting a holistic view. Beside predictable latency
times, trustworthiness of messages is a major aspect
since safety relevant decisions have to be based on
remotely collected information to overcome line-ofsight
limitations. Security measures based on cryptographic
algorithms have to be employed which typically
demand for a huge amount of computational
power. In Fig. 8 these facts are illustrated by means of
Fig. 9: V2X-gateway architecture.
a single vehicle that is connected through a V2X interface
to a smart environment which allows data exchange
between external and internal network consisting
of a complex interconnection structure of sensor
and actuator systems.
In this context we developed a FPGA-based V2X
gateway architecture (see Fig. 9) [7] which follows the
last North American and European standardization
efforts [8]-[10]. By integration of V2X functionality
into a central automotive gateway, a direct link between
the VANET network and the internal vehicular
bus network is provided. The approach opens the
internal automotive E/E architecture to the outer
VANET. Therefore, the central gateway is divided
into an Inter-Vehicle-Networking-Domain (InterVND
and an Intra-Vehicle-Networking-Domain (IntraVND).
The main aspects which make this approach
different are as follows:
• Modularization: Typically occurring tasks are
distributed on specific modules. These work in
parallel and allow processing of V2X messages in
discrete steps. Each of the modules consists of
different hardware and software components and
fulfill a dedicated task like e.g. message evaluation,
routing, signature generation/verification or
information processing. Thus the overall gateway
itself forms a heterogeneous multicore device.
Self-X characteristics have been embedded into
the system wherever possible e.g. by utilizing partial
dynamic reconfiguration.
• Communication Architecture: Packets are passed
from one module to the successor in the processing
chain by means of a realtime capable on-chip
packet-based transmission bus system [11]. Especially
in situations like traffic jam when the own
vehicle is surrounded by dozens of other vehicles
and the system runs near maximum capacity, a
fast forwarding of crucial information must be
guaranteed in order to comply with the strict latency
requirements. Accelerating packet propagation
is achieved by prioritized packet forwarding
through prioritized scheduling and prioritized re-
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