How Simulation Tools Save Time and Money When Verifying Sensor Performance in V2X Designs

May 4, 2021

Cellular Vehicle-to-Everything (C-V2X) was initially developed to serve as a vehicle communication technology to improve traffic, comfort, efficiency, and safety. Now, it is in the pole position to serve as the technology to lead us to the autonomous vehicle age. To do so, however, simulation and test tools must be developed to efficiently, accurately, and repeatedly conduct measurements on sensors to ensure operation in mission-critical environments.

One reason C-V2X is leading the way is utilization of 5G New Radio (NR). Deployment of 5G NR is enhancing all C-V2X elements – vehicle-to-vehicle (V2V), vehicle-to-pedestrian (V2P), vehicle-to-infrastructure (V2I), and vehicle-to-network (V2N). The high speed and low latency of 5G NR builds a strong foundation for safety use cases, including autonomous vehicles.

C-V2X’s Global Impact

Integration into self-driving vehicles is the logical next step for C-V2X. Various New Car Assessment Programs (NCAPs) around the world are already implementing the communications technology in current connected car use cases. Leading the way is China, as it is committed to a considerable deployment of C-V2X vehicles and infrastructure. Europe is also active, as evident by a new European Standard (EN) positioning C-V2X as an access layer technology for the Intelligent Transportation System (ITS) developed by the European Telecommunication Standardization Institute (ETSI).

Figure 1: C-V2X is a key enabling technology for autonomous vehicles (photo courtesy of dSPACE).

Initial C-V2X deployments in the U.S. are underway, fueled by a recent decision from the Federal Communications Commission (FCC). In November 2020, the FCC adopted new rules that designate the upper 30 MHz (5.895-5.925 GHz) for ITS services and C-V2X as the technology standard for safety-related transportation and vehicular communications. The action by the FCC begins a transition away from Dedicated Short-Range Communications (DSRC) services, thus eliminating one key roadblock in C-V2X becoming the technology of choice for autonomous vehicles.

Autonomous vehicles will utilize emerging communications modes and schemes, such as sidelink and collective perception, respectively. Each leverages C-V2X with 5G NR and integrates multiple sensors, including cameras, radar, and LiDAR. Simulation testing of these sensors are a requirement during design and manufacturing at the device, system, and vehicle levels.

Sidelink and C-V2X

Sidelink, also known as PC5, allows vehicles and roadside units (RSUs) to communicate reliably and directly with each other without the cellular network. To deliver high reliability, C-V2X sidelink relies on blind hybrid automatic repeat request (HARQ), which transmits the same data packet at least twice, each with a different coding. The receiving vehicle reconstructs the original message using both transmitted messages.

3GPP Release 16 5G NR, which includes notifications and maneuvers such as lane changes, outlines the direct communication mode in C-V2X sidelink. 5G NR C-V2X sidelink brings several enhancements, such as higher throughput, lower latency, enhanced reliability, and improved positioning. All are expected to improve autonomous driving. 5G NR C-V2X sidelink also moves the default mode of operation from broadcast to more reliable multicast communication.

Figure 2: 5G NR is aiding in the C-V2X evolution (photo courtesy of Qualcomm).

C-V2X Impact on Collective Perception

Collective perception is especially promising, as it allows connected traffic participants to “see through the eyes of others” by sharing sensor-detected objects via C-V2X. The information exchanged via collective perception allows vehicles to detect objects in their respective Local Environmental Models (LEMs).

Traffic participants and infrastructure use the data collected to inform connected stations of objects, such as pedestrians, obstacles, and other vehicles. The object data are exchanged through Collective Perception Messages (CPM). ETSI is standardizing CPM to ensure its interoperability among all equipped vehicles.

Scenario-based Testing

There are many scenarios, such as number of vehicles and surrounding infrastructure, that need to be properly identified for autonomous vehicles to operate safely. For this reason, verification solutions must conduct scenario-based testing with realistic simulation and 5G network emulation. There must be comprehensive environment simulation with support of trajectory to properly calculate maneuverability.

Device, system, and automotive engineers need to verify that these sensors will operate efficiently before the models reach the road. Utilizing a cellular network simulator provides multiple financial and operational efficiencies compared to conducting the necessary measurements over a live cellular network. Two critical advantages are:

Repeatability – You can’t predict live network performance, but you can with a cellular network simulator. All key parameters – power, channel, data rate, network settings, etc. – can be controlled. The result is repeatable measurements.

Efficiencies – A network simulator allows engineers to emulate real-world scenarios. This creates tremendous cost-of-test and time benefits, as teams don’t have to travel the world conducting measurements on various networks.   

The Anritsu Signalling Tester (Base Station Simulator) MD8475B and Radio Communication Test Station MT8000A are integrated into the dSPACE V2Cloud Solution to create an effective simulation environment. The dSPACE solution provides an integrated development and test environment for data logging and enrichment; machine learning and in-vehicle prototyping; data replay; production software development; scenario generation; and vehicle, environment, and sensor simulation.

One example of the solution’s advantage is conducting measurement-based handovers, an important test for autonomous vehicles. The Anritsu-dSPACE solution can emulate handovers as they are actually done on the live network, as shown in figure 3. The mobile device sends channel quality data reports to the network simulator, which then emulates a threshold for handover. The system makes it easy to simulate complex scenarios, such as roaming and saturation, from anywhere in the world. Handover test cases are built into the GUI to simplify taking measurements and making updates as standards progress.

Figure 3: Network simulators can emulate the complexity of real-world networks such as the one shown here.

You can learn more about conducting C-V2X tests and verification using simulation tools by watching this C-V2X webinar conducted by Anritsu and dSPACE.