V2X paves the way for AVs and connected cars

Autonomous vehicles (AVs), capable of operating without human intervention, are one of the most advanced and fascinating developments in the automotive sector. Using advanced sensors and AI techniques such as machine learning (ML), autonomous driving aims to improve road safety and provide a more comfortable driving experience. Connected cars go one step further, using wireless connectivity to communicate with other vehicles, road and network infrastructure, and even pedestrians in the vicinity of the vehicle.

At the heart of this evolution is vehicle-to-everything (V2X) communication, an innovative technology that allows vehicles to interact with their surroundings in real time. V2X improves road safety by allowing cars to share critical information about speed, direction, and potential hazards, thereby reducing the probability of accidents. It is also important in traffic management, helping to alleviate congestion and improving mobility efficiency, especially in urban areas.

Components of AV technology

Two key components are needed to implement AV technology: advanced sensors to monitor the environment in which the vehicle is traveling and communication systems that enable interaction with other entities in the vicinity, such as vehicle-to-vehicle (V2V) and vehicle-to-device (V2D) communication.

Sensors

The primary sensors used in AVs include vision cameras, LiDAR sensors, radar, and ultrasonic sensors. Other sensors, such as the global navigation satellite system, inertial measurement units, and vehicle odometry sensors, are used to determine the relative and absolute positions of the vehicle.

Sensors are critical in AVs for environmental perception and vehicle localization for route planning and decision-making, which are necessary to manage vehicle movements. Many sensors, such as LiDAR or cameras, incorporate AI algorithms that help classify objects such as traffic signals even in difficult environmental conditions, such as rain or fog.

ML models can distinguish authentic signals from noise thanks to training on large datasets. This allows noise to be eliminated from the acquired data. It also allows even the weakest signals to be considered, which might otherwise be overlooked.

For example, Iteris Inc.’s Vantage Apex hybrid sensors combine 1080p high-definition (HD) video with 4D radar and AI algorithms to provide precise vehicle detection and object classification. The company was recently awarded a $1.7 million contract by the city of Burleson, Texas, to execute an advanced traffic management system (ATMS) plan. The system enables the detection, tracking, and classification of vehicles, pedestrians, and cyclists and includes an HD video display for monitoring a traffic management center (Figure 1). The objective is to improve the management of traffic flow and the city’s mobility.

Figure 1: Traffic management center (Source: Iteris Inc.)

Another 4D development is Aeva Inc.’s 4D LiDAR sensors, leveraging frequency-modulated continuous-wave (FMCW) technology. It can detect not only the position of surrounding objects (x, y, and z coordinates) but also their instantaneous velocity.

Aeva recently announced that Inyo Mobility, a leader in autonomous urban transportation solutions, has chosen Aeva as its exclusive LiDAR supplier for its upcoming autonomous shuttle program. Aeva Atlas 4D LiDAR sensors, using FMCW technology and proprietary digital-signal-processing algorithms, will be integrated into Inyo’s AV platform with the goal of improving safety, perception, and operational efficiency in complex urban environments. Inyo CAB (Figure 2) is a fully electric modular vehicle designed for sustainable last-mile urban mobility.

Figure 2: The Inyo CAB AV integrates Aeva’s 4D LiDAR to improve environmental perception. (Source: Aeva Technologies Inc.)

V2X technology

V2X technology enables the real-time sharing of information between an AV and other road users in the immediate vicinity, including dynamic entities such as other vehicles, pedestrians, and cyclists, as well as static elements such as traffic lights, signs, and road markings. As shown in Figure 3, this includes V2V, vehicle-to-infrastructure (V2I), vehicle-to-network (V2N), vehicle-to-pedestrian (V2P), and V2D communication.

Figure 3: Key components of V2X technology (Source: Stefano Lovati)

V2X includes the following communication modes:

V2V enables cars to directly exchange data, such as velocity, position, and direction, which helps drivers avoid crashes by giving early warnings about hazards or risky situations. For example, warnings about lane changes, the presence of vehicles in blind spots, or stationary vehicles in dangerous positions, are essential in V2V.
V2I allows vehicles to connect with road features such as traffic lights and sensors. V2I can optimize traffic flow and safety by transmitting real-time information between vehicles and infrastructure.
V2P focuses on communication between vehicles and pedestrians, often using personal mobile devices. V2P can mitigate potential accidents by notifying drivers of nearby walkers and cyclists, and vice versa. Advanced V2P systems can detect pedestrians even when they are not visible to drivers, reducing the risks of collisions. The evolution of electric mobility has introduced a new category of vulnerable road users (VRUs), represented by electric scooters. Euro NCAP provides specific safety tests to protect VRUs.
V2N connects vehicles to wider networks, such as cloud services and ATMSes. This communication allows the vehicle to access real-time information and services, such as navigation (traffic congestion, road work, or hazardous conditions such as objects on the road).
V2D is a broader term encompassing how vehicles interact with various linked devices, such as smartphones, wearables, or smart home systems.

V2X communication technologies

Current implementations of V2X technology for AVs and connected cars use two wireless communication systems: dedicated short-range communication (DSRC) and cellular-V2X (C-V2X). DSRC, the technology developed first, uses Wi-Fi (IEEE 802.11p standard) in the 5.9-GHz frequency band. The more recent C-V2X technology is based on mobile networks, including 5G infrastructure.

With a longevity of over 20 years, DSRC was designed for low-latency communication within a range of 300 to 1,000 meters. Suitable for V2V and V2I communications, DSRC uses a frequency band that was reserved for ITS by the U.S. Federal Communications Commission (FCC) in 1997. In 2020, a portion of this frequency range (the lower 45 MHz of the initially allocated 75 MHz) was allocated for unlicensed Wi-Fi communications.

Despite being successfully tested and implemented in pilot projects across the U.S., Japan, and Europe, DSRC has some limitations. These are primarily related to its restricted operational range and poor penetration in non-line-of-sight (NLOS) conditions. The limited available bandwidth also makes it less reliable in urban areas, densely populated with vehicles.

C-V2X is based on the LTE and 5G cellular standards developed by the 3rd Generation Partnership Project. C-V2X offers superior range and coverage over DSRC due to its utilization of existing cellular infrastructure. It can also operate in NLOS conditions, which is an advantage in urban environments with a high density of buildings and obstacles.

Additionally, the cellular infrastructure (4G/LTE or 5G) allows for the simultaneous connection of multiple vehicles without issues of available band congestion, which can happen with DSRC. C-V2X is well-suited for V2N applications, such as dynamic traffic management and over-the-air software updates.

In 2024, the FCC adopted final rules for C-V2X, aiming to accelerate the automotive industry’s transition from DSRC to the more advanced C-V2X automobile safety technology. This decision permits in-vehicle and roadside units to operate C-V2X in the 5.9-GHz spectrum band, which is dedicated to ITS.

Autotalks, a fabless semiconductor company now part of Qualcomm Technologies Inc., specializes in V2X communication solutions for both manned and autonomous vehicles. They provide a range of products that support both DSRC and C-V2X technologies. The Qualcomm V2X 350 chip, currently in the sampling phase, is a sensor designed to support all V2X radio technologies, including DSRC, LTE-V2X, and the latest 5G-V2X.

This advanced SoC can operate two radios simultaneously, each equipped with dual antennas and full transmit/receive diversity for robust performance. It also integrates ultra-low-latency hardware security modules to ensure secure communication. Thanks to these features, the V2X 350 can achieve ISO 26262 ASIL-B functional safety certification, making it the first V2X solution to support automatic braking capabilities.

In collaboration with Autotalks, Murata Manufacturing Co. Ltd. has launched a wireless module solution portfolio (Figure 4) specifically designed to support V2V and V2I communications. The 2AN and 1YL modules, built around Autotalks’ V2X chipsets, support both DSRC and C-V2X communication standards. A key advantage is their ability to operate in different geographic regions (Europe, Asia, North America, etc.) using the same module, simply by adjusting the software configuration.