By Christoph Mutz, Senior Automotive Product Marketing Manager, Western Digital
The automotive industry is going through profound changes as connected vehicles become the norm. With every technological development, innovation and smart addition to the vehicle, each car becomes in itself, a server on wheels. From increasingly centralised architecture, to in-depth infotainment consoles, the sheer amount of data cars now create presents challenges when it comes to the car’s storage requirements.
While urban infrastructure and the development of edge data centres will be key to the eventual success of connected and autonomous transport, the need for on-board data storage has never been more prevalent. There are current on-board flash storage solutions such as the embedded Multi-Media Chips interface (eMMC), but the need for higher performance to transfer data to and from the systems in the car requires a faster interface. To help manage the sharp rise in fast data, the Universal Flash Storage (UFS) interface offers a suitable solution for the next generation of vehicles. But what are the benefits of flash storage, and how is the technology solving the industry’s challenges?
Changing automotive architectures and the impact on data
Automotive architectures are changing dramatically, from dispersed control units to one centralized system in a car. Previously, an Electronic Control Unit (ECU) had a specific function according to its use case. These ECUs eventually became connected to each other, but the networks still acted independently of one another. With gateways, it is now possible to achieve coordinated cross-network communication, enabling the handling of increasingly complex, data rich-tasks. Furthermore, in merging the individual ECUs into domain controllers (DCU), providing the ability to handle many demanding tasks at once, the architecture now can evolve even further. For the software, it means that in addition to the computing algorithms such as those used in artificial intelligence (AI), it also affects the operating system with its virtualisation techniques like the use of hypervisors.
Therefore, the evolution of the architecture is now having an impact on important components in processors and flash storage. Regarding flash, the required ever-higher storage capacities can be supported by NAND flash technology. The unique requirements of the industry must also be considered, with the advanced algorithms increasing the need for NAND flash with its ability to provide very high capacity at very low cost in automotive applications.
How UFS is solving on-board storage challenges
UFS has emerged as the first choice for high data throughput, with shorter write and read sequences, in conjunction with high capacity storage. Originally developed for mobile devices, UFS offers next-generation vehicles the benefits derived from its development and optimization in mobile radio technology, a field that is subject to high technical demands, and the processing of large amounts of data. Alongside the benefits of high-level data throughput and storage capacity, UFS provides the opportunity for an industry standard platform. The standardisation consortium JEDEC, continues to drive the development of UFS Technology, with UFS 4.0 expected in 2022 and further versions set to follow.
With flash providing clear benefits in an automotive setting, the question now resides in how much storage the connected car needs, and which applications require the most space?With its large amount of map data, navigation has been the main application creating a large demand for flash memory in recent years. Currently, navigation and all the elements that inform the driver and make up ‘infotainment’ are the main beneficiaries of large storage capacities using up to 256 GB of flash in certain vehicles. With higher resolutions needed for automated driving and 3D mapping data, as well as other information at the driver’s fingertips on the dashboard, this is only set to continue to grow with up to one terabyte (1TB) per car expected by 2025. UFS, with its faster interface, offers a much snappier transport of such large amounts of data, significantly improving the user experience.
The technology behind flash storage and its benefits
The most critical features of NAND flash memory in cars are reliability, write endurance and data retention. A wide variety of factors can strongly influence the latter, for example the way in which data is written from the application to the flash, which has a strong impact on its lifetime. This is because small data packages stored at arbitrary addresses place a greater load on the flash than large amounts of information that is saved all at once.
Innovations within UFS storage are allowing flash to be protected from intensive operations. Flash technology can now enable read-intensive and write-intensive applications to run on separate partitions, made possible by ‘smart partitioning’. Partitions configured as a Single Level Cell (SLC) structure are particularly suitable for write-intensive programs. Here, the flash is reduced to a third of the capacity of the Triple Level Cell (TLC) structure, but the number of write cycles is many times higher. Read-intensive programs can then use the partition with the TLC structure, providing the full storage capacity and extending the service life within UFS memory significantly.
With data now imperative to the functioning of connected vehicles, the reliability of data storage is essential to the car’s overall safety. UFS innovations now allow for a detailed recording of the write or read events, making it possible to analyse the read-write behavior of the application and determine if it is at risk of distressing the flash due to unbalanced workloads. It can do this by recording ‘events’, or the individual data throughputs, based on the “UFS Protocol Information Units” (UPIU). After careful analysis of this data, insights into the write/read behavior of the system can be gained and interpreted, protecting the performance of the flash, and significantly extending the reliability and security of the data.
Driving collaboration between OEMs and storage manufacturers
3D NAND technology has primarily established itself in automotive electronics with the ability to create higher flash capacities. With this, the technology can scale and meet the future demand from automotive applications for increasingly large memories. With larger capacities, fewer flash modules are needed. This means they can then be installed in central locations reducing the hardware costs that would have been incurred if they were installed in a distributed manner.
The changes in the electrical-electronic (E/E) architecture of cars in recent years will only accelerate. As mentioned, the formerly numerous Electronic Control Units (ECUs) are networked with many of the vehicle’s parts; and the concentration into ever larger Domain Control Units (DCUs) is in full swing. Future architectures will undoubtedly bring further innovations and with the stronger role of software, this means that large automotive companies will be increasingly looking for suitable processors and flash components. Therefore, closer communication between OEMs and the flash manufacturers is soon to be of paramount importance to the future of the connected car, providing the opportunity to find the optimal use of processors and memories, minimising the failure probabilities and increasing the service life.