V2X Communication Test Tool for Scenario-Based Assessment of Truck

Platooning

Jacco van de Sluis

1 a

and Jan de Jongh

2 b

Integrated Vehicle Safety Department, TNO Automotive, Helmond, The Netherlands

Networks Department, TNO ICT, The Hague, The Netherlands

Keywords:

Truck Platooning, ITS, V2X Communication, V2V Communications, Virtual Testing, Hardware-in-the-Loop

(HiL) Testing, Scenario-Based Assessments.

Abstract:

The EU-funded ENSEMBLE project

∗

designs, realizes, tests and validates novel multi-brand platooning tech-

nology for trucks in a consortium consisting of all European truck OEMs, ﬁrst-tier suppliers, branch organisa-

tions and academic and research institutes. This paper describes the project’s approach towards (intermediate)

testing of the V2X communications, speciﬁcally focusing at Hardware-in-the-Loop (HiL) testing through the

use of a custom V2X Test Tool developed in ENSEMBLE. The tool enables scenario-based assessment of

truck platooning with the newly deﬁned platooning protocol and (pre-standard) V2V messages. Next to V2V

message conformance testing, it offers V2X communication functional testing and performance testing ca-

pabilities for different platooning scenarios. The V2X Test Tool is used for veriﬁcation and validation of

platooning solutions, and facilitates the next steps of testing truck platooning at proving grounds and in real-

life environments.

1 INTRODUCTION

The last decade platooning technology and research

has made many advances, but the step towards real-

life deployment of truck platooning still needs to be

taken. It is the ambition of the EU project ENSEM-

BLE (ENSEMBLE Consortium, 2022) to use a multi-

brand truck platooning approach and to deﬁne In-

telligent Transport System (ITS) standards for inter-

operable truck platooning in Europe. For this, the

speciﬁcations for a multi-brand truck platooning con-

cept has been worked out. Important parts of the spec-

iﬁcation are newly deﬁned protocols for the platoon-

ing interactions and V2V (Vehicle-to-Vehicle) com-

munication message sets. A platooning ”reference

design” is developed to realize a generic platooning

implementation (non-brand speciﬁc). This is used by

the partnering truck manufacturers to prepare for the

multi-brand testing and the demonstration of the EN-

SEMBLE truck platooning concept. All six European

truck OEMs are involved in the project.

https://orcid.org/0000-0002-7162-6014

https://orcid.org/0000-0001-7868-5909

∗

This project is co-funded by the European Union under

the Horizon 2020 (H2020) Research and Innovation Pro-

gramme (grant agreement No 769115).

The platooning concept describes the functional

architecture together with a minimum set of require-

ments and speciﬁcations for the platooning opera-

tional and tactical layers. The main building blocks

are the use cases, the in-vehicle system requirements,

the platoon V2V communication function and pla-

tooning management and maneuvering coordination

functions. V2X (X for everything) communication

technology is a important enabler for safe platooning

of trucks at short following distances (Ploeg, 2014).

State of the art on truck platooning technology and

related research projects are presented in (Willem-

sen et al., 2018). Generic V2X testing is addressed

in (Wang et al., 2019), where (Gao et al., 2016) fo-

cuses on V2X simulation tooling for platooning ap-

plications. In (Voronov et al., 2015) the focus is on

an interactive test tool enabling remote V2X commu-

nication testing, which includes speciﬁc communi-

cation Hardware-in-the-Loop (HiL) setups. Speciﬁc

platooning HiL-based testing is further addressed in

(Schindler et al., 2019). For scenario-based assess-

ment (Op den Camp et al., 2021) and (Sluis et al.,

2021) identify V2X testing capabilities, test scenarios

and approaches for truck platooning.

Speciﬁc test tools need to be developed for the en-

gineering activities (veriﬁcation & validation) and the

van de Sluis, J. and de Jongh, J.

V2X Communication Test Tool for Scenario-Based Assessment of Truck Platooning.

DOI: 10.5220/0011700500003479

In Proceedings of the 9th International Conference on Vehicle Technology and Intelligent Transport Systems (VEHITS 2023), pages 135-143

ISBN: 978-989-758-652-1; ISSN: 2184-495X

 2023 by SCITEPRESS – Science and Technology Publications, Lda. Under CC license (CC BY-NC-ND 4.0)

135

assessments of the ENSEMBLE platooning concept.

This paper explains the ENSEMBLE V2X Test Tool

developed for testing the V2V communication func-

tion and platooning protocol interactions. It identi-

ﬁes V2V testing capabilities, suitable test scenarios

and challenges which needs to be addressed as part

of truck platooning assessments. The V2X Test Tool

enabled the OEMs to develop and test their (mono-

brand) implementations against the ENSEMBLE ref-

erence design, and already locally prepare for multi-

brand testing.

The remainder of this paper is organized as fol-

lows. Section 2 describes the truck platooning con-

cept with the platooning protocol design. Section 3

gives the main assessment methods of truck platoon-

ing, and Section 4 describes in detail the developed

platooning V2X Test Tool and its capabilities. And

Section 5 concludes with our ﬁndings and outlook for

future work.

2 TRUCK PLATOONING

CONCEPT

Truck platooning can potentially make road transport

safer, cleaner and more efﬁcient (ACEA, 2017). V2X

communication plays an important role in enabling

vehicle platooning. Two or more vehicles equipped

with automated driving support systems are linked to-

gether via V2V communications. Figure 1 gives a

high-level overview of the ENSEMBLE platooning

layers as deﬁned in (Willemsen et al., 2022). The

reference design to be implemented and tested is de-

ﬁned as a ”Platoon Support Function” (PSF) for the

driver, who also acts as back-up and is responsible

for monitoring the driving task. In addition a Platoon

Autonomous Function (PAF) has been deﬁned, which

does not rely on a driver as back-up (in the follow-

ing vehicles) so a high level of automation is needed

and therefore it is currently not part of the reference

design.

Referring to Figure 1, the vehicle control compo-

nent is part of the operational layer; it is responsible,

with its actuators and controllers, for the execution of

the vehicle and platoon maneuvering like accelerat-

ing, braking, and steering. The vehicle sensors used

as input for the PSF are also part of this operational

layer.

The PSF resides mainly at the tactical layer,

which is for decision-making and coordination of the

platoon. The PSF supports platoon manoeuvres like

platoon forming (joining/leaving the platoon), keep-

ing ”platoon cohesion” (for example on hilly roads)

and keeping the desired speed and inter-vehicle dis-

tance when platooning. Finally, another important

part of the tactical layer is the platooning protocol

used for supporting the platooning interactions.

Figure 1: Illustration of the ENSEMBLE Platooning layers

(Willemsen et al., 2022).

The strategic layer supports the high-level

decision-making related to (route) planning, schedul-

ing, optimisations for travel time, trafﬁc situations etc.

This layer connects to the service layer at which logis-

tics operations can interact.

2.1 V2X Platooning Protocol

One of the key goals of the ENSEMBLE project

is stating the speciﬁcations for a V2X communica-

tion protocol to enable inter-operable platooning us-

ing wireless communication (Atanassow and Sj

oberg,

2022). These speciﬁcations describe how vehicles in-

form each other about their platoon capabilities, and

deﬁne the V2V message set and respective data for-

mats for the exchange of data supporting the deﬁned

platoon manoeuvres (e.g. driving in the platoon, join-

ing a platoon).

The V2V messages used are:

• The Cooperative Awareness Message (CAM)

(ETSI, 2019b) for broadcasting vehicle informa-

tion. Within ENSEMBLE, the original CAM is

extended with an isJoinable ﬁeld to announce that

a vehicle can be part of a platoon, provided that

all prerequisites for safe platooning are met.

• The Platoon Management Message (PMM) for

managing a platoon (Atanassow and Sj

oberg,

2022). The PMM is a newly deﬁned message us-

ing event-based communication for handling Join

Request, Join Response and Leave interactions.

The interactions which are part of the Join actions

also involves sharing speciﬁc platoon capabilities

amongst the members and setting up a secure (en-

crypted) communication channel for the platoon.

• The Platoon Control Message (PCM) for intra-

platoon exchange of operational and tactical data

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136

to support the PSF (Atanassow and Sj

oberg,

2022). As PMM, the PCM is a newly deﬁned mes-

sage; PCM message exchange takes place over

the secure communication channel. Every pla-

toon member transmits PCMs at a high update

rate (20 Hz) and the information is used for ve-

hicle control functions like adaptive cruise con-

trol (ACC), emergency braking and platoon ma-

neuvering (normal platooning, platoon cohesion).

Figure 2 gives a simpliﬁed view of the V2V mes-

sage exchange between two vehicles, from joining a

platoon, actual platooning, up-to leaving the platoon.

Figure 2: Platooning interactions from joining to leaving

(Atanassow and Sj

oberg, 2022).

The interaction starts from an IDLE mode situa-

tion and the Leading Vehicle (LV) announcing that it

can be part of a platoon by setting the boolean ﬂag

isJoinable in its CAMs to True. A vehicle indicated

as Following Vehicle (FV) receiving the CAMs from

the LV, and interested to platoon can send out a PMM

”Join Request”. Meeting certain conditions the ve-

hicles transmitting or receiving a Join Request will

move to a JOIN mode (isJoinable=False for other idle

vehicles).

Once the LV has decided that it accepts the FV for

joining, the LV transmits a (positive) Join Response

(PMM) containing additional platoon information, a

security key and all the information needed to set-up a

secure channel for PCM exchange. The LV also starts

transmitting its PCMs and when it receives PCMs

from the FV it will move to PLATOON mode. The FV

also moves to PLATOON mode when the LV starts its

PCM transmissions. The role of the FV then changes

to Trailing Vehicle (TV) as it is the last vehicle of the

platoon, but this is left out of the ﬁgure. Note that

vehicles in PLATOON mode are always transmitting

and receiving PCMs.

Just like the LV previously, the (now) TV can

again transmit CAMs with isJoinable=True, allowing

other vehicles to join the platoon from behind. In that

case, a candidate vehicle (i.e., a third vehicle wanting

to join the two-vehicle platoon) then interacts with the

TV of the platoon, and not directly with the FV.

A vehicle ends up in LEAVE mode either when

PCMs have not been received from the other vehi-

cle(s) during some predeﬁned time period, or because

the ego-vehicle decides to leave the platoon which is

shared by transmitting a PMM Leave message ending

PCM transmissions.

In addition to the message set and protocol inter-

actions, a V2X security framework for platooning is

speciﬁed in (Atanassow et al., 2022). Starting point

for this is the existing public key infrastructure (PKI)

developed for C-ITS (ETSI, 2017b). All broadcast

messages are signed and veriﬁed using temporary au-

thorization tickets. (This mechanism is to a large de-

gree application agnostic.) For secure end-to-end pla-

tooning, application-speciﬁc encryption is used for all

PCMs to provide additional conﬁdentiality. PMMs

are used for the exchange of the platooning security

keys and their updates (security keys are updated reg-

ularly).

The security framework adds, next to the offered

protection, also a layer of complexity. For reasons of

simplicity, platooning security is considered out-of-

scope in this paper, because on the PSF tactical level

this does not change the protocol operational logic or

platooning interactions.

2.2 Platooning Scenarios

The ENSEMBLE platooning protocol is designed to

support the interactions of the PSF. The deﬁned set

of platooning use cases are described in (Willemsen

et al., 2022), together with speciﬁcations on platoon

characteristics, relevant high-level platooning maneu-

vers, Human Machine Interface (HMI) interactions

and environmental conditions. The scenario deﬁni-

tions include information of the maneuvers, the spe-

ciﬁc Operational Design Domain (ODD) conditions

and relevant ”events” (for example cut-in vehicle,

emergency braking, system failures). A use case is

a combination of a scenario description together with

a set of initial and ﬁnal conditions, and a deﬁned set

of interaction sequences.

The supported high-level maneuvers in the pla-

toon are:

• Platoon engage: Platoon Join, Merge in between

• Platooning: Steady-state Platooning, Platoon gap

adaptation.

V2X Communication Test Tool for Scenario-Based Assessment of Truck Platooning

137

• Platoon Disengage: Platoon Leave, Platoon Split.

These are the main platooning maneuvers as part of

the PSF which are supported by the V2V platooning

protocol, and these are also the relevant test scenarios

considered for the V2X Test Tool.

The ”Joining from behind by a single vehicle” sce-

nario is used as an example test case of a Platoon en-

gage manoeuvre. In Figure 3 the Start situation is the

ego vehicle as a Candidate Member (CM) and is driv-

ing behind an truck (LV) that is joinable for platoon-

ing (announced via its CAM). Like mentioned before,

Figure 3: Join from behind by a single vehicle scenario.

some pre-conditions have to be met for the ego vehi-

cle and LV. The platooning systems needs to be oper-

ational, the vehicles are in communication range with

no other vehicles in-between. The ego vehicle driver

activates the platooning function. As the ego vehicle

is receiving the isJoinable information from the LV,

the system can start the joining procedure. In Step 2,

the ego vehicle request to join by transmitting PMM

Join Request. The LV receives the Join Request mes-

sage, evaluate the correct joining conditions and sends

a PMM Join Response (accept) message. In step 3 the

engage action is ﬁnalised, the ego vehicle and LV are

ending the join procedure with the exchanged PCMs

which are used to close the distance-gap to an agreed

time-headway value. The ego-vehicle is part of the

platoon (PL1) and is now the Trailing Vehicle (TV)

of the platoon. It can now itself transmit isJoinable

announcements via its CAMs.

3 ASSESSMENT METHODS OF

TRUCK PLATOONING

The scenario-based assessment methodology of

(H2020 Project HEADSTART, 2020) mention four

main testing methods: Virtual Testing (VT), XiL-

based (for everything-in-the-loop), Proving Ground

(PG) and Field testing (FT). The methodology is used

for safety assessment of Connected and Cooperative

Automated Driving applications, and uses the truck

platooning application as a selected use cases for as-

sessment. V2X communication is normally not part

of the available scenarios descriptions and extensions

are needed to include V2X communication in the used

testing methods. In the following sections each test-

ing methods is brieﬂy described for the truck platoon-

ing scenarios.

3.1 Virtual Testing

To test scenarios virtually, a framework for enabling

the execution of the appropriate scenario descriptions

is needed. This top-level is needed for control and

management of the virtual testing environment. Also

it contains scenario modelling functions with ele-

ments for the static environment (for example high-

way road layout) and the dynamic environment (for

example other vehicles). Then for the PSF, different

functional blocks can be identiﬁed for:

• Driving functions.

• Vehicle dynamics.

• Sensors.

The driving function relates to the PSF and other au-

tomated driving functions. This also includes the pla-

tooning decision-making functions based on sensor

inputs. The sensor block gets all its input from the

virtual environment. The model accuracy highly de-

pends on the provided ﬁdelity of the sensor data. The

actions coming from the driving functions are passed

to the vehicle dynamics block, that contains the vir-

tual vehicle model as part of the PSF.

3.2 XiL-based Testing

X-in-the-loop (XiL) based testing is a method of test-

ing that combines VT with real hardware implemen-

tations. The amount of virtual and real elements can

vary greatly: from only having a single platform, sen-

sor or actuator as part of a Hardware-in-Loop (HiL)

set-up, up to having a complete vehicle-in-the-loop

(ViL). The XiL-based testing is often a good compro-

mise between proving ground testing which is very

realistic and VT that allows for testing a higher num-

ber of scenarios. Our work focus on testing the V2X

communication functions as part of the PSF. The V2X

Test Tool includes the communication hardware, of-

ten called on-board unit (OBU) with the V2V com-

munication software supporting the PSF tactical func-

tions. Speciﬁc test scenarios have been developed for

assessing the supported PSF maneuvers, the related

platooning protocol interactions and V2V message

exchanges. The platooning scenarios enables V2V

assessments for: conformance testing of the V2V pla-

toon messages; functional testing of the platooning

VEHITS 2023 - 9th International Conference on Vehicle Technology and Intelligent Transport Systems

138

protocol; and performance testing of the V2V com-

munication and the PSF at tactical layer level.

3.3 Proving Ground Testing

Proving Ground testing is a key part for assessing the

performance of automated driving systems. For truck

platooning full system performance can be evaluated

as part of the single vehicle, and with the vehicle as

part of the platoon, in a real-world environment. This

is not possible with the VT and XiL-based solutions,

PG testing is often the ﬁrst opportunity to do platoon-

ing testing with actual driving vehicles and execute

scenarios with platoon speciﬁc manoeuvres (example

Platoon Join). Execution of the platooning scenarios

and related test cases are always in the context of opti-

mization costs and effectively using available PG time

and resources.

3.4 Field Testing

Field Testing or open road testing often follows suc-

cessful PG testing. For truck platooning, its aim is to

test the PSF in the real world and evaluate the platoon

maneuvering in its deﬁned ODD. Route selection is

important to have suitable roads with the correct re-

quired infrastructure elements. For truck platooning,

the test plan and test case deﬁnitions need to address

the local regulations and exemptions required to be

able to execute PSF testing on public roads.

4 V2X TEST TOOL FOR

PLATOONING

In order to meet the requirements for early XiL-based

testing of communication and interaction protocols

within ENSEMBLE, a V2X Test Tool has been de-

signed, realized and deployed. The next sections de-

scribe its design guidelines, architecture and various

components.

4.1 Design Guidelines and Architecture

For the design of the V2X Test Tool, the following

considerations and guidelines were adhered to:

• Portability: The V2X Test Tool must run on var-

ious hardware platforms and under various Oper-

ating Systems (Windows, Mac, Linux). For this

reason, a Java-based system was designed. This

requirement was particularly important as the tool

was intended to be run by the project partners on-

site.

• Ease of Use: The software should be easy to use,

in order to accommodate the diverse nature of the

end users. For this requirement, it was important

to realize that end users come from varying back-

grounds (control, software engineering, automo-

tive, . . .).

• Single-Screen Status and Control: The con-

trol and status reporting of the V2X Test Tool

should be implemented using a single ”all-in-one”

screen, to the extent possible.

• Modularity: The software should be designed

and realized in agreement with modern software-

engineering views on modularity, object orienta-

tion and information hiding. This requirement

hopefully assists in smooth integration of other

applications and/or modules.

• Reuse of existing hardware and software: To the

extent possible, the V2X Test Tool should be

constructed using existing (TNO or open-source)

reusable software components and libraries.

• Version Control: The V2X Test Tool was realized

while the ENSEMBLE platooning protocols had

not fully crystallized yet. It was therefore crucial

for the V2X Test Tool to be able to run different

revisions of the platooning protocol, even side-by-

side.

• Low Cost (to the end user): Through the use of

Java technology instead of the perhaps more com-

mon MATLAB/Simulink environment, the end

user saves on licensing costs and is given the ﬂex-

ibility to quickly (re)deploy the tool. All that is

needed is a Java©virtual machine.

In view of the fact that TNO has had an experi-

mental On-Board Unit (OBU) in operational use for

several years, it was decided to reuse reuse this com-

ponent. The OBU allows for reception and transmis-

sion of ITS-G5 frames in the ITS-G5A Band (and

others) (ETSI, 2020), using a UDP-based protocol to

transfer payload and frame control data to and from

the clients.

The V2X Test Tool architecture is shown in Figure

4. The box on the left represents the V2X Test Tool

Java software, consisting roughly of a Graphical User

Interface and running a single instance of a V-ITS-

S (Virtual ITS Station) and multiple so-called V2X

Tests. The top-right shows the OBU connected to the

V2X Test Tool. The bottom right shows the Device

Under Test.

4.2 On-Board Unit

The On-Board Unit provided with the V2X Test Tool

in the ENSEMBLE project is shown is Figure 5. In

V2X Communication Test Tool for Scenario-Based Assessment of Truck Platooning

139

Figure 4: The V2X Test Tool architecture.

its most common setup it consists of an PCEngines

APU board running a modiﬁed Linux kernel that al-

lows for operation of a standard PCI Express WLAN

card on ITS-G5. On top of that, a software compo-

nent named btpsap implements the GeoNetworking

(ETSI, 2017a) and Basic Transport Protocol (BTP)

(ETSI, 2019a) as well as the security functions within

GeoNetworking (encapsulation into and decapsula-

tion out of a security envelope and signing and ver-

ifying messages). The btpsap software communi-

cates with its client over a TCP connection and one

or more UDP streams. The interface deﬁnition of

btpsap is publicly available (de Jongh et al., 2018),

which allows for third-party alternative implementa-

tions based on for instance cellular communications.

Figure 5: The On-Board Unit deployed with the V2X Test

Tool.

4.3 V2X Test Tool Capabilities

The tool has the following capabilities:

• Sending and receiving CAM, CAM+ (with isJoin-

able extension) and platooning-speciﬁc messages:

PMM, PCM. Both the CAM/CAM+ and PCM

message rates are user conﬁgurable.

• Logging messages.

• Presenting decoded messages in real-time.

• Deﬁning so-called Virtual ITS Stations that are

capable of interacting with the System under Test

(SuT), e.g., by pretending to be a following vehi-

cle wanting to join the SuT in a platoon.

• Maintaining a Local Dynamic Map on each V-

ITS-S.

• Running a simpliﬁed (e.g., by omitting several

sanity checks) platooning controller on each V-

ITS-S.

• Using a variety of sources for the position of a

V-ITS-S, e.g. making it follow another V-ITS-S

through the use its received CAM messages.

• Run multiple versions of the platooning protocol.

• Perform platooning test scenarios (join, leave,

platoon), in the different roles (LV, FV, TV, CM).

Currently, the V2X Test Tool focuses at logical

interactions needed to test the platooning protocol.

Issues related to the wireless medium (packet loss;

transmission latency) are currently not in scope. It

is conceivable, though, to deﬁne packet-loss test sce-

narios.

4.4 Virtual ITS Station

A key feature of the V2X Test Tool is that of a Virtual

ITS Station (V-ITS-S). A V-ITS-S represents a station

in software with options to connect to for instance a

real-world GPS sensor or OBU. That way, the soft-

ware implementing the V-ITS-S can be subjected to a

variety of tests. A simple test, for instance, is to check

whether the GPS sensor data (like position ﬁxes) are

properly encoded in transmitted CAM messages.

The V-ITS-S implementation is highly modular,

allowing for application-speciﬁc modules providing

custom message sets and/or application logic. For

ENSEMBLE, a dedicated platooning module was de-

veloped with support for CAM+, PMM and PCM

messages (in various stages of development) and for

platooning (V2X) protocols.

The primary use of a V-ITS-S is to test platoon-

ing implementations of project partners on site using

(e.g.) a laptop running JAVA connected to a supplied

OBU. We were therefore able to test, in an early stage,

the non-trivial ASN.1 encoding and decoding of the

platooning messages, and at least ensure message in-

teroperability.

4.5 Position and Time

The provisioning of position and time estimates to

V-ITS-S instances, to the OBU and to the V2X Test

Tool itself is of crucial importance. At the same time,

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140

given the ﬂexibility of the tool, some noteworthy vari-

ations in the setup are possible. An example of the

appearance of Position and Time controls in the GUI

of the tool is shown in Figure 6.

For time, a V-ITS-S can use either the system time

or connect to a gpsd (Various, 2022b) instance. In ei-

ther case, time-warping is implemented; allowing for

a ﬁxed offset with the real time. This has proven use-

ful for replaying scenarios with trace data like mes-

sage exchanges. Using the system time is the eas-

iest setup and most appropriate for systems that al-

ready have time synchronization set up at the required

stratum level (e.g., through ntpd (Various, 2022c) or

chronyd (Various, 2022a)). Using gpsd as a source

for both position and time is most convenient for con-

necting the V-ITS-S with the external OBU. Due to its

reliance on accurate position and time in order to run

GeoNetworking, the OBU is already equipped with a

GPS receiver and running gpsd instance. As warping

in time, position warping is supported as well, trans-

lating each position update to a different area on the

globe.

Figure 6: The Position and Time panel in the V2X Test Tool

GUI.

Two interesting alternatives for position update

are ﬁle-based updates (successive positions are taken

from ﬁle) and follow mode, in which position updates

are such that it ”follows” another station at a cer-

tain distance. This is particularly useful for bench-

testing controllers in distance-dependent applications

like platooning.

4.6 Local Dynamic Map

In the V2X Test Tool, each V-ITS-S is equipped with

a Local Dynamic Map (LDM) (ETSI, 2014), a table

holding recently heard stations through (for instance)

CAM messages. Since by virtue of (ETSI, 2019b),

ITS Stations are obliged to always send CAMs, it is

relatively easy to maintain a view on the ”local neigh-

borhood” in each V-ITS-S . By its very nature, the

LDM is application-agnostic, yet the implementation

allows for application-speciﬁc extensions (message

sets, ﬂags, . . .).

In the LDM, ITS stations are indexed by their ITS

Station ID. An example of the appearance of the LDM

in the GUI of the tool is shown in Figure 7.

Figure 7: The Local Dynamic Map in the V2X Test Tool

GUI.

4.7 Test Scenarios

The V2X Test Tool supports the following (auto-

mated) test scenarios:

• Sending and receiving CAM(+) messages.

• JOIN: The V-ITS-S attempts to join the ITS Sta-

tion the SuT represents. After successful comple-

tion of the join request and join response message

exchange, the V-ITS-S starts sending, as required,

PCM messages and expect PCM messages from

the station it joined.

• BE JOINED: The V-ITS-S prepares to be joined

from behind by the SuT. For instance, it signals its

willingness to be joined in the CAM+ messages it

transmits. It then expects a join request, checks

the request and if applicable, sends a positive re-

sponse. It then checks for subsequent transmis-

sion of PCM messages by the DUT.

• LEAVE: The V-ITS-S leaves the platoon it is cur-

rently part of (it may be in front or behind the SuT

station).

4.8 Abstract Platooning Model

As mentioned earlier, the V2X Test Tool has a speciﬁc

module for platooning support. The module, however,

was realized using a more abstract platooning model

than the one designed in ENSEMBLE.

In the ﬁrst model, the concept of platooning is

seen, from a V2X perspective, as a highly controlled

temporary unidirectional association between two sta-

tions, the front and rear vehicles, respectively. The

main protocol components then become the join and

leave operations, and the duties that come with the

association once created, like sending dedicated state

messages (PCMs in the case of ENSEMBLE).

V2X Communication Test Tool for Scenario-Based Assessment of Truck Platooning

141

The platooning model in the tool focuses on the

separate communication interactions between a sta-

tion and its predecessor and successor (whenever ap-

plicable). In the bottom line of the platooning pane

in the V2X Test Tool, shown in Figure 8, the platoon-

ing state of the front and rear controllers are shown

through indicators (Platooning State [local]). The in-

dicator in the middle signals that platooning is com-

plete in former sense: both front and rear controllers

are connected to another station, and the platoon is in

steady state (no ongoing join or leave actions).

Figure 8: The Platooning (application) pane in the V2X Test

Tool.

The main advantage of using a somewhat more ab-

stract model for platooning is that it allows for quick

adaption to changes in the concrete (ENSEMBLE)

platooning protocol, as long as the protocol ﬁts in the

model. In particular, we rarely needed changes in the

V2X Test Tool GUI despite the frequent changes in

the ENSEMBLE protocol. Finally, it allowed the use

of the V2X Test Tool while designing the protocol

itself. Certain protocol features during design could

thus be evaluated in an early stage.

5 FINDINGS

The ENSEMBLE V2X Test Tool was designed, re-

alized and deployed in an early stage of the speciﬁ-

cation of truck platooning in ENSEMBLE. It proved

its use as a veriﬁcation and validation tool, for debug-

ging and testing, conformance testing of the V2V pla-

tooning message sets, and also served as a protocol-

assessment tool. As mentioned earlier, the tool proved

a great help to ensure message interoperability at a

relatively early stage of the ENSEMBLE project. It is

essential to have such a tool, because current available

commercial V2X communication tools does not sup-

port the non-standard project-deﬁned platooning mes-

sage sets, or the relevant test scenario for platooning.

Other advantages include its use as a debugging

tool in Field Testing (since the tool features frame

capturing and analysis). Also it is possible to use

the tool for performance analysis, for example by us-

ing stress testing scenarios with: high message loads;

higher updates rates; high number of Station ID’s;

etc. Another option for performance analysis is creat-

ing failure scenarios by using wrong messaging (for-

mat, timing, protocol logic, message drop, etc.) for

testing the robustness of the platooning protocol and

higher application layers. The main performance re-

sults from the ENSEMBLE project are available in

(Kalose and Goos, 2022); reﬂections on the v2x pro-

tocols can be found in (Mascalchi et al., 2022).

Finally, the development of the V2X Test Tool

itself required an early in-depth analysis of the EN-

SEMBLE protocol, which resulted in useful feedback

during protocol design. In a way, it forced the early

implementation of the ENSEMBLE message sets and

protocol logic long before the ﬁnalization of the pla-

tooning speciﬁcations.

In the near future, we hope to fully implement the

security features of the ENSEMBLE protocol, in par-

ticular transmitting and receiving the symmetrically

encrypted PCM message. Together with security test

scenarios for the validation of the security function-

ality and for identifying possible vulnerabilities and

threats. Thus offering useful veriﬁcation and valida-

tion feedback as a security engineering tool for taking

mitigating actions against security threats. Also, we

intend to reuse the V2X Test Tool in future Cooper-

ative Automated Driving and ITS projects aiming at

development and implementations of novel message

sets and protocols. And to extend it with subsequent

suitable testing scenarios supporting the cooperative

interactions.

The source code for the V2X Test Tool is available

upon request for research purposes.

ACKNOWLEDGEMENTS

The authors wish to express their gratitude to Sandesh

Manganahalli Jayaprakash, Daan Ravesteijn, Ramon

de Souza Schwartz, Harry Wedemeijer and Bastiaan

Wissingh, all at TNO, for their help during the design

and implementation of the V2X Test Tool.

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