Keysight Technologies
New Strategies for Managing Wireless
System Complexities in the Connected Car
Application Note
Anite is now part of Keysight Technologies
Introduction
The automotive industry is preparing to deploy the next phase of the connected car evolution which
incorporates a wide range of technologies for various wireless connectivity services. These services can be
split into two main categories. The first category deals with the improved safety and traffic management
possibilities that car-to-car connectivity and enhanced navigation systems create. The second category
addresses the applications that linking the car to the internet via cellular and wireless broadband enable.
In the face of rising wireless system complexity, automotive manufacturers will need to continue to invest
in extensive testing to ensure connectivity performance and reliability are maintained over the lifecycle of
the vehicle. Development time and cost is likely to increase substantially as a result of this surge in testing.
This paper highlights several development challenges that arise from the implementation of complex
vehicle wireless systems and discusses how the automotive industry can easily adopt test methodologies
used in the mobile industry, where testing is typically conducted in the early stages of the development
cycle when issues are less complicated, time-consuming and expensive to rectify. This would enable the
automotive manufacturers, Tier 1 suppliers and module manufacturers to significantly reduce the development time and cost associated with delivering their connected car vision.
03 | Keysight | New Strategies for Managing Wireless System Complexities in the Connected Car - Application Note
Increased Car Connectivity Complexity Drives Testing
Needs
End-users are likely to increase their expectations of mobile connectivity performance
and many analysts suggest that in-vehicle quality of experience will have a significant
impact on the connected car market’s development rate. In the case of information
services, the quality of experience – in terms of coverage and connection speed – will
need to exceed those levels already established in the rapidly evolving consumer mobile
market. In the case of safety and traffic flow management, other parameters such as
connection reliability and robustness will also prove vital.
From a development perspective, it is quite challenging to deal with an increased
level of wireless connectivity complexity while simultaneously improving reliability and
robustness. This situation can easily lead to a steep rise in the risk of finding an issue
that requires major redesign in the later stages of vehicle development or even when
the vehicle is being used. In recent times, several high performance handset1 platforms
from leading manufacturers have suffered from the ‘death grip’ syndrome where simply
holding a device in a certain way changes the antenna sensitivity by over 10 dB. Despite
rigorous testing and certification, this defect was only detected in the field. The material
complexity and operating environment of a vehicle is obviously much greater than that of
a mobile device, which means that the scale of the verification problem also increases.
WiFi
802.11 b g n
ac ad ax
ITS
802.11p
ITS-G5
Bluetooth
4.2+
NFC
Satellite
GPS GLONASS
Galileo Baidou2
GSM
850 900
1800 1900
UMTS
850 900
1900 2100
LTE
800 850 900 1800
2100 2600
5G
2020
WiFi
802.11
b g n ac
Bluetooth
4.1
NFC
Satellite
GPS
GLONASS
GSM
850 900
1800 1900
UMTS
850 900
1900 2100
LTE
800 850 900 1800
2100 2600
2015
WiFi
802.11
bgn
Bluetooth
2.1
Satellite
GPS
2010
WiFi
802.11
bg
Bluetooth
2.0
GSM
850 900
1800 1900
UMTS
850 900
1900 2100
y
xit
ple
om
c
st
Te
ply
tee
gs
n
i
ris
GSM
850 900
1800 1900
2005
Test cases
Figure 1. Test complexity rises as the connectivity mix expands
Typically, automotive manufacturers perform extensive vehicle wireless connectivity
testing in the later stages of the development cycle and rely heavily on road drive
testing. Manufacturers adopt this approach because predicting or simulating the impact
of vehicle structure on radio performance prior to assembly of the prototype has proven
difficult and highly unreliable. Due to the sharp rise in test complexity, Tier 1 suppliers
and vehicle manufacturers normally conduct most of the wireless related testing when
material construction of the prototype is relatively mature. As a consequence, next
generation connectivity platforms are expected to have a considerable impact on test
time and cost, with some analysts estimating a five to ten fold increase2 in test cost and
time compared to today.
1. ‘Antennagate’ – http://www.pcmag.com/
encyclopedia/term/62034/antennagate
2. European Commission Connected Car
Agenda
04 | Keysight | New Strategies for Managing Wireless System Complexities in the Connected Car - Application Note
Connecting the Vehicle to the Internet
Future applications, including enhanced traffic information services, multimedia
services, vehicle relationship management (VRM) services and baseline emergency call
capabilities, will rely on the quality and reliability of the vehicle’s ability to connect to the
wireless network. Although LTE is the preferred radio access technology option for next
generation systems, cellular networks will also need to provide backwards compatibility
with 2G/3G in order to provide consistent service delivery. The evolution of cellular
networks is primarily driven by requirements set by mobile platforms, not the automotive
market. This may impact the way some of these future applications are developed and
tested.
Because of the huge volume of data that in-vehicle systems are expected to create,
vehicle service connectivity is likely to be provided by both the conventional cellular
network and Wi-Fi (through LTE/Wi-Fi data offload). This means that in order to deliver
the medium term baseline service vision, automotive wireless connectivity solutions
embedded into the vehicle will need to support LTE, 3G and 2G, as well as Wi-Fi 802.11
air interfaces. Each air interface needs to be tested separately across the worst-case
network conditions that the vehicle is likely to encounter. Additionally, interoperability
between each air interface also needs to be tested. Testing modem redundancy is also
important for meeting reliability requirements.
Na
v ig
o
ati
e
ns
es
r v ic
le r e la t io n s h ip ma n a g e m e n t
V e h ic
Eme
rg e
n cy
re p
or
t in
g
Cellular
2G • 3G • 4G
rt
Satellite
a le
Wi-Fi IEEE 802.11p
ITS-G5
f f ic f
hi
Ve
nt
ra
cle t
lo w m a n a g e m e
ck in g a n d t h e f t
Tr a
Vehicle to Roadside
Infrastructure
GPS • GLONASS
Baidou2 • Galileo •
INRSS
Sa
Vehicle to Vehicle
Communication
Radar
fet
Wi-Fi IEEE 802.11p
ITS-G5
77/79 GHz
ys
y st
em
In-car services
s
Bluetooth • Wi-Fi
In f o t a i n m e n t
Mu lt i
m
st
e d ia
re a
mi
Figure 2. Connected car – wireless technologies and use cases
ng
05 | Keysight | New Strategies for Managing Wireless System Complexities in the Connected Car - Application Note
Emergency call mandates (eCall and ERA-GLONASS)
At a recent automotive conference1, a panelist was asked whether or not extensive
cellular performance test and network compliance is really necessary and replied
in the affirmative by highlighting the importance of rigorously testing features such
as emergency call (eCall). European governments have mandated that this feature
must be integrated into every new car sold after 2018. Russia has similarly mandated
ERA-GLONASS be integrated in every new car to be sold after January 2017. The aim of
this initiative is to reduce accident response time to half the current average. To achieve
this target, cellular connectivity (2G/3G/LTE etc.) to emergency services must be
established immediately and maintained long enough to report the location and scale of
an incident that is reported by the driver or automatically triggered, for example, by the
release of an airbag
Intelligent transport systems (V2X)
Vehicle safety solutions – Vehicle to vehicle (V2V) and vehicle to infrastructure (V2I),
collectively referred to as V2X – also need to be tested. The drivers behind deploying this
technology are clear. In the US alone, over 400,000 accidents occur annually, with a total
economic impact estimated at 800 billion US dollars, close to 2% GDP2,3. V2X connectivity using Dedicated Short Range Communication (DSRC) is based on extensions to
the Wi-Fi standard (802.11p). Many countries in Europe, USA, Japan, South Korea,
and Australia are running trials to deploy this technology, which means that yet another
significant air interface needs to be tested. The U.S. Department of Transportation (DOT)
is working towards regulation which will make DSRC for V2V mandatory for all cars very
soon.
Ensuring wireless connectivity performance and reliability
Vehicle navigation systems as well as location reporting for emergency call services, rely
on satellite communication, specifically GPS (USA), Galileo (EU), GLONASS (Russia) and
BeiDou (China). From a wireless test perspective, satellite data reception needs to be
tested in isolation and in coexistence with reliable interaction between the cumulative
on-board wireless systems listed above. Other vehicle wireless air interfaces that need to
be validated include in-car Bluetooth and Wi-Fi radios operating in the ISM band4.
From an integration perspective, multiple radio transceivers within the vehicle are in very
close proximity. This means that the transmit power of one transmitter may be much
higher than the received power level of another receiver. In many cases, with intelligent
use of contemporary filter technologies and sufficient frequency separation, the transmit
signal does not cause significant interference.
However, for some coexistence scenarios such as different radio technologies within the
vehicle operating on adjacent frequencies, current state-of-the-art filter technology may
not provide sufficient rejection. This problem is further compounded by the fact that final
material composition of the vehicle is not known until late in the development cycle and
consequently interference modes and paths become increasingly difficult to predict in
real-world network connection scenarios. For example, when integrating navigation and
cellular wireless systems, automotive manufacturers need to fully test the satellite data
reception in isolation as well as in co-existence with active on-board wireless systems
under worst case conditions. For collocated LTE and GNSS systems, LTE Band 13 (UL:
777-787 MHz) /14 (UL: 788-798 MHz) can interfere with the L1/E1 frequency of GNSS
(1575.42 MHz) as it is close to the second harmonics of band 13/14 (1554-1574 MHz for
band 13, 1576-1596 MHz for band 14).
1. TU Automotive Detroit Conference June 2015
2. http://www.usatoday.com/
story/news/nation/2014/05/29/
steep-economic-toll-of-crashes/9715893/
3. TU Automotive panel session, Nevada State
Legislator presentation
4. The industrial, scientific and medical (ISM)
radio bands are radio bands (portions of the
radio spectrum) reserved internationally for
the use of radio frequency (RF) energy for
industrial, scientific and medical purposes
other than telecommunications.
06 | Keysight | New Strategies for Managing Wireless System Complexities in the Connected Car - Application Note
Reducing Late Stage Drive Testing
Virtual Drive Testing
Toolset streamlines
the performance and
interoperability testing
process from early
R&D lab evaluation
through to field testing
and optimization.
Although the automotive industry is relatively conservative in nature and reluctant to move
away from established best practices, some progressive organizations are evaluating
solutions from wireless testing specialists such as Keysight Technologies, Inc. with the
aim of making real-world field conditions available much earlier in the development cycle.
The mobile device industry, with its a strong focus on performance, low cost and shorter
development cycles, uses test methodologies that could be easily adopted by the automotive industry7.
Virtual drive testing is an example of a test methodology that has been proven to accelerate
product rollouts and quality assurance testing in the mobile industry. Keysight’s Anite
Virtual Drive Testing Toolset is a lab-based performance and interoperability test solution
that integrates industry-leading lab and field test tools with a sophisticated test automation
environment. Virtual drive testing provides the ability to cost effectively verify the end-user
quality of experience and significantly reduces field testing through accurately replicating
vehicle field drive testing. With Keysight’s Anite Virtual Drive Testing Toolset, automotive
manufacturers can capture and record a number of parameters including network settings,
signaling to the car module, responses from the car module, radio (RF) environment in and
around the car based on the traffic and reflections from other cars, buildings, trees etc. in
addition to satellite signals such as GPS, GLONASS, Galileo and BeiDou.
Data captured in the field is used to build tests that replay drive routes in a virtual environment by emulating real-world RF network conditions in the laboratory. This replay can
be performed in combination with Keysight’s Anite 9000 network simulator. The Keysight’s
Anite Virtual Drive Testing Toolset’s powerful automation capability enables repetitive
testing of virtual field test routes for different use case scenarios. This leads to reliable and
cost-effective device benchmarking and resolution of issues found in the field during the
early stages of product development.
GSM
WCDMA
Carrier
Aggregation
Campaign
Manager
Device A
Device B
Device B
Volte
eICIC
LTE
HSPA+
MIMO
Wifi
Toolset Control PC
Toolset Control PC
The Toolset Control PC offers powerful automated and repetitive trialling of
virtualised field test routes for different use case scenarios
TD-SCDMA
LTE-A
Air Interface Emulation
TCU
or
Propsim F32
Anite 9000
Figure 3. Virtual Drive Testing Toolset uses data captured in the field to build tests that replay routes in a virtual
environment by emulating real-world RF network conditions in the laboratory
1. Measurement uncertainty, channel
simulation, and disturbance characterization of an over-the-air multi-probe setup
for cars at 5.9 GHz (http://lup.lub.lu.se/
record/7760628)
07 | Keysight | New Strategies for Managing Wireless System Complexities in the Connected Car - Application Note
Automotive over-the-air (OTA) performance testing is used to assess the user’s experience
when accessing vehicle onboard data services by replicating real-world conditions as seen
by the vehicle antenna cluster. When a radio wave interacts with an object, the wave is
scattered, diffracted, reflected or absorbed. Radio channel emulation aims to accurately
replicate this behavior. Recreated RF network conditions include: multipath propagation,
Doppler Effect, angles of departure (AOD), angles of arrival (AOA), and noise/interference,
as well as all of the typical channel conditions between the base station or access point
and the vehicle antenna cluster.
Automotive OTA testing uses channel emulators in an anechoic chamber (non-reflective) to
accurately emulate different radio environments such as urban, suburban, rural, and indoor
areas. Recently, the mobile device industry (via CTIA) has standardized MIMO OTA testing
in order to accurately assess the performance of a device. This testing methodology can be
effectively used in vehicle wireless connectivity development.
Keysight has contributed substantial channel emulation expertise to the CTIA MIMO OTA
subgroup (MOSG), which has been investigating MIMO OTA performance since March 2011.
The subgroup has recently agreed (with support from all CTIA operators), to move forward
with two different types of OTA activities, and both recommendations have been adopted
by leading independent test houses in China, Taiwan, Europe and US who are deploying
anechoic MIMO OTA test laboratories.
Test Chamber
Propsim channel emulator
PA
TCU
or
LNA
Base Station
Emulator
95%
Uplink
Control
GPIB/LAN
Figure 4. Automotive OTA testing to assess end-user experience when access data services
Keysight works with Tier 1 mobile operators worldwide to develop acceptance test cases
that device manufacturers use to ensure their products perform as expected when
launched. Major modem chipset, reference design and wireless product manufacturers
run these scripts in SAS (Keysight’s interoperability and performance test solution, which
uses the Keysight’s Anite 9000 network simulator) during product development and
conformance test cycles.
Such capability supports automotive system development, as it enables the data throughput performance of in-vehicle software and hardware modules to be tested against mobile
operator requirements from multiple geographic regions under real-world network conditions prior to final integration into the vehicle. This strategy has the potential to drastically
reduce the amount of performance related test needed by highlighting system issues that
impact quality of experience much earlier in the vehicle development cycle.
Automotive OTA
performance testing
is used to assess the
user’s experience when
accessing vehicle
onboard data services
08 | Keysight | New Strategies for Managing Wireless System Complexities in the Connected Car - Application Note
Conclusion
Discussions in technical forums, automotive industry journals, and conferences as well
as feedback from vehicle manufacturers all confirm that the automotive industry clearly
understands wireless test complexity and associated issues. There is however a prevalent
view that meaningful wireless connectivity testing is not realistic prior to integration of the
Telematics Control Unit and the antenna cluster in a mature vehicle prototype. Experience
from the mobile wireless industry strongly suggests otherwise: test strategies based around
the Keysight’s Anite Virtual Drive Testing Toolset, Keysight’s Anite 9000 network simulator
and the Propsim channel emulator, enable early stage wireless connectivity and system
performance tests in the laboratory that can easily be replicated and fine-tuned later in the
vehicle prototype as well as in the field. By adopting these test methodologies, automotive
manufacturers can significantly reduce costs and time in the development phase.
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© Keysight Technologies, 2016
Published in USA, November 9, 2016
5992-1725EN
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