Advantages of Concurrent Dual-Channel V2X

Chafik Driouichi

V2X Senior Product Manager

Vehicle-to-everything (V2X) is a breakthrough technology that could significantly improve road safety and save thousands of lives every year. Developed and tested over decades, V2X uses wireless communications to give vehicles 360-degree visual awareness of their surroundings, beyond their visual range, up to one kilometer away.

The only mature and ready-to-deploy V2X solution uses the DSRC [1] /IEEE802.11p wireless standard, which enables vehicles to communicate directly with each other, roadside infrastructure, pedestrians, and everything else. Initial benefits include early warning of traffic accidents to increase safety and intelligent traffic management to improve the smoothness of traffic flow. Looking ahead, V2X will play a key role in enabling autonomous driving.

UBX-P3: Developed entirely in-house by u-blox

After launching two successful generations of u-blox V2X modules based on third-party V2X chips , we announced the UBX-P3 chip earlier this year, our completely in-house built V2X solution. Not only does the UBX-P3 strengthen our offering for the entire DSRC/IEEE 801.22p market, but the bottom-up approach also gave us the freedom to design the chip to meet the needs we observed in the market. One of these needs was to enable concurrent dual channel communications.

If you know anything about the automotive industry, you know that it is heavily regulated to ensure high quality standards are met. The same is true for V2X, which applies to your car’s airbags, brakes, and windshield wipers. Ensuring that all safety messages are received, whether from other vehicles or nearby infrastructure, is essential to keeping you safe.

The IEEE 1609.4 multi-channel operation standard enables this operation with a single radio switching channels. So why do we implement concurrent dual-channel communications on a V2X chip?

It’s simple. Two eyes can see more than one. The same is true for V2X receivers, which can help improve reliability, robustness, and ultimately safety on the road.

Image from EDN Electronic Technology Design

Understanding DSRC/IEEE 802.11p Channels

Before we dive into how to take advantage of concurrent dual-channel V2X communications, let’s first understand some basics of DSRC/IEEE 802.11p V2X communications.

In Europe and the United States, the DSRC/IEEE 802.11p spectrum covers 75 MHz in the 5.9 GHz band and is divided into seven channels. In both regions, one channel is used as a control channel. Two (Europe) or six (US) of the remaining channels are service channels that can be dedicated to specific communications. South Korea has adopted a similar setup to Europe and the United States, while Japan has reserved a 10 MHz channel centered at 760 Mhz for the technology.

The picture comes from Electronic Enthusiasts. DSRC technology includes on-board units and roadside units, which can support two-way data transmission between vehicles and between vehicles and roadside equipment.

Single-channel V2X solutions are more cost-effective than dual-channel solutions due to their simple design. However, since single-channel solutions have only one receiver channel to monitor multiple communication channels, the available bandwidth for monitoring safety messages is reduced by at least 50%, thereby reducing the safety benefits and reducing the number of deployable applications. Dual-channel operation can improve the safety benefits of V2X by tuning one channel to receive safety messages, while the other channel can be used for other applications.

Key use cases for concurrent dual-channel communication

Depending on the situation, dual-channel V2X can be configured to continuously follow both communication channels to ensure that no safety messages are missed. Alternatively, one receiver can be set up to always keep a pulse of incoming safety messages while the second receiver alternates between the control channel and the service channel .

Another interesting use case is truck platooning, where trucks travel in a compact formation to reduce air drag on the following vehicle, thus reducing fuel requirements by more than 13%. V2X is the technology of choice for ensuring the safety of truck platooning, even at high speeds. With concurrent dual-channel communication, one of the available channels can be dedicated to communication between two trucks, while the other channel handles communication with surrounding vehicles.

Image source: https://baijiahao.baidu.com/s?id=1613033980077956471&wfr=spider&for=pc "How V2V enables truck platooning"

UBX-P3 is the smallest and most power-efficient V2X chip on the market. It is designed to meet the most stringent automotive applications, is safe and fully compliant with major global standards, and has an integrated power management unit. In addition to concurrent dual-channel communication, UBX-P3 has other highlights. It can provide comprehensive coverage for vehicles by using two antennas to communicate simultaneously on the same channel, leaving no communication blind spots.

[1] DSRC stands for Dedicated Short Range Communications.