Although they can all be classified as cars, there are huge differences between the models of previous generations and those that are presented today, a disparity that is set to increase in the future. The high degree of complexity that can already be seen in car design allows for the incorporation of many new features that improve safety, operating efficiency and the overall driver experience. The evolution of mechanical systems towards purely electronic systems, known in general terms as x-by-wire (x by cable), allows the weight of the vehicle to be reduced, thus improving its fuel consumption. In the same way, the availability of advanced driver assistance systems (ADAS) offers much higher levels of protection to road users, and it is only the beginning. In the years to come, technological advancement will take the car further away from its origins.
One of the main objectives of car manufacturers is to promote the concept of "connected car", which will bring us closer to the long-term goal of autonomous driving. Vehicles, thanks to their use of a greater number of communication technologies, will be able to offer functions and capabilities previously unthinkable. Wireless technology (supported by a high-bandwidth Ethernet-based wired backbone) forms the foundation on which connected cars will be built. This communication between vehicles (vehicle-to-vehicle, V2V) and between the vehicle and the infrastructure (vehicle-to-infrastructure, V2I) will make it possible. In this article we will review the various wireless communication protocols that are set to feature in future car designs.
Main wireless technologies
The incorporation of Wi-Fi to cars is becoming more and more common. At this stage, the design is especially focused on 802.11ac technology, which can easily achieve data rates in the hundreds of Mbps. It provides a connection path between portable electronic devices (such as smartphones) and computers. infotainment and vehicle navigation systems, as well as a means of sharing a cellular connection (thus offering a Wi-Fi hotspot in and around the car). However, there are other aspects to take into account. It is admitted that the evolution of the useful life of the car is much slower than in the consumer segment. Rather than the vehicle having permanently fixed functionality, unable to take advantage of new developments as they emerge, it is necessary to provide for its upgrade, but without the inconvenience of having to take the car to a garage.
This means that access to firmware updates over the air (firmware-over-the-air, FOTA) via Wi-Fi will be very advantageous. 802.11ac-based Wi-Fi is complemented by the latest version of the Bluetooth wireless protocol. Bluetooth 5 will undoubtedly be a valuable asset for the advancement of connected cars. Its range is much greater (four times the distance covered by Bluetooth 4), as well as the speed offered by previous versions. As a result, Bluetooth 5 will have many applications. In addition to allowing vehicle occupants to connect their portable devices, thus accessing music sharing services and hands-free control functions, as well as numerous other potential benefits. The increased performance of Bluetooth 5 means that the vehicle has the ability to interact with distributed beacons that will be part of the V2I network. Through this it will be possible to pay tolls, make payments for congestion and access various information services.
It is expected that, thanks to the use of V2I, traffic will be more fluid and the probability of traffic jams will be greatly reduced. Vehicles will be able to get information about traffic light cycles, so ADAS will be able to determine if it's better to slow down and be just in time when the light turns green, rather than having no information and simply braking as the car approaches. at a red light. All this will reduce fuel consumption. The emerging 802.11p standard is set to achieve widespread adoption in vehicles. Originating from the established 802.11-based Wi-Fi, it builds on its enduring success and effective ubiquity, but is purpose-built to meet the challenges of in-car installation. It uses the 5,9 GHz frequency band and 7 communication channels (each with a width of 10 MHz), of which 6 are service channels and 1 additional channel is dedicated to control tasks.
The goal of 802.11p is to provide a very high reliability and low latency connection through which V2V and V2I communication is established. Thus, it will support Intelligent Transportation System (ITS) applications as they are deployed. Thanks to this system, vehicles will be able to send data related to their current position, the direction in which they are moving and their speed. In a V2I context, this technology could be used to transfer data between cars and the surrounding infrastructure, allowing for early warning of traffic jams, accidents and other situations, as well as knowing available parking spaces. In a V2V context, it could also give vehicles the ability to communicate with each other, so that information about potential hazards identified by one vehicle is passed on to nearby vehicles. Advanced wireless technologies, such as those reviewed in this article, are set to play a critical role in keeping the cars on our roads connected.
The increased range enabled by Bluetooth 5, the ability to deliver high data rates of 802.11ac, and the implementation of 802.11p to ensure that Wi-Fi is fully effective for high reliability and low latency in the car, all of them are very attractive aspects. Marvell's engineering team, who have been working in the automotive industry for years, recognize the challenges that arise when it comes to high performance and robustness. Making connected cars a reality requires sophisticated and highly integrated solutions that incorporate various wireless technologies into compact, automotive-approved packages.
The recently announced 88W8987xA series is a clear example in this regard. These AECQ100-certified wireless system-on-chip (SoC) devices are the first to support Bluetooth 5, 802.11ac Wi-Fi (Wave 2), and 802.11p, giving engineers the flexibility they need to meet the growing demand for wireless connectivity in vehicles. The series consists of 3 devices with the same form factor: an 802.11ac with Bluetooth 5, an 802.11p with Bluetooth 5, and a switchable 802.11ac/802.11p device with Bluetooth 5. Engineers therefore have different options that will allow them to offer a cheaper platform with fewer resources.
Different versions can be selected depending on the car model, from economy models with basic functionality to luxury models with high-end capabilities. Since these devices can be interchanged without the need for PCB modifications, a vehicle model's feature set can be upgraded, making it future-proof.
