Introduction
In January 2018, ABI Research authored a white paper examining the cost structures of two V2X technologies; IEEE 802.11p standard and 3GPP Release 14 C-V2X. In particular, this white paper considered two potential integrations of these technologies into an LTE TCU architecture featuring Wi-Fi (single band) connectivity. The white paper was highly focused in scope, considering the immediate opportunities for the integration of these two technologies to address a narrow, mission-critical application common to both technologies, with an accompanying functional safety requirement. ABI Research would like to take this opportunity to further educate the market and elaborate on the assumptions made in the white paper, how these assumptions informed architecture choices, and how these assumptions drove the cost difference between the 802.11p+LTE and C-V2X+LTE architectures considered in the report.
An important addition to the previous report that ABI Research would like to clarify at this juncture is the assumption around royalty / licensing strategies. It is quite clear that the silicon leader in the C-V2X space, Qualcomm, is not charging an additional royalty fee for 3GPP Release 14 functionality over the typical, sub $5 per 3G/4G module or telematics control unit. As LTE is common to both architectures considered within the whitepaper, the royalty / licensing costs would also be common to both 802.11p+LTE and C-V2X+LTE, leading to no cost difference in this aspect.
Functional Safety in Cooperative Mobility
The majority of the cost difference calculated in the whitepaper was driven out by the functional safety requirement tied to the mission-criticality of the safety-centric application considered. The guiding philosophy of the automotive state-of-the-art ISO 26262 functional safety recommended practices is one of enabling “safety by design” through hardware and software techniques which provide adequate guarantee of access to resources and non-interference for safety-centric functions. The hazard and risk assessment methods covered in the standard currently has a vehicle-centric focus, although there is an ongoing discussion in the industry on how the principles of functional safety can be best applied in the context of cooperative mobility. Furthermore, safety relevant systems (or items) that are defined at the system level (such as obstacle detection / collision avoidance) may incur a functional safety burden on V2X components; this very much depends on the specific architecture choices made by the OEM. In the whitepaper, ABI Research set out measures that C-V2X vendors could potentially adopt to ensure synchronization and non-interference in conjunction with a strict functional safety requirement.
However, it is important to recognize that many OEMs are not presently requiring stringent V2X system integrity, even in safety focused applications, especially as low penetration will limit the role of V2X inputs in the sensor fusion process for active safety applications in the short term. Some OEMs have no current requirement. For instance, in the support of many OEM objectives, the use of GNSS signals for positioning and synchronization will be valid, particularly as positional data (the core of V2X basic safety messaging) will be lost before synchronization in urban canyons, tunnels etc. Furthermore, as GNSS is needed to get location information for both V2X technologies, its reuse for C-V2X time synchronization improves cost-effectiveness. Given that the architecture assumptions which informed much of the cost difference between the 802.11p+LTE and C-V2X+LTE integrations were due to the functional safety requirement, ABI Research concludes that for many implementations C-V2X and 802.11p will have a comparable cost structure.
ABI Research expects that as penetration grows, the functional safety requirement for V2X will increase, particularly in cooperative mobility use cases. Nevertheless, it is important to recognize that over this time horizon, there are opportunities for further integration on the C-V2X front, in particular the integration of C-V2X with the LTE modem, which would yield substantial cost advantages for C-V2X. This is even more significant when considering the proliferation of LTE connections in passenger vehicles, not only to support the established connected infotainment use cases, but increasingly to support functions relating to sensor data crowdsourcing and OTA maintenance of software-defined functions in connected vehicles.
Further Architecture Considerations: Integrating Wi-Fi in the TCU
The typical automotive practice to date has been to incorporate Wi-Fi into the infotainment control unit, though many in the automotive industry expect Wi-Fi to be integrated into the TCU in order to provide a dedicated gateway which is separated from infotainment functions. It is important to note that if an OEM is looking to support concurrent operation of dual-band 2.4/5 GHz Wi-Fi alongside 802.11p, they will face the additional cost of multiple 802.11 chipsets as there is currently no 3 PHY/MAC available on the market to support 2.4/5/5.9 GHz.
Considerations beyond Cost
Decision makers in the automotive space do not only consider cost but also the feature richness of technologies when making their strategic investment decisions. C-V2X direct communications functions, as defined in 3GPP Release 14 published in 2017 provides longer range or higher reliability at the same range, as well as support for high speed use cases. Furthermore, network based connections made over cellular infrastructure can enable a host of compelling use cases, including warnings about broken-down vehicles further ahead, or guidance to vacant parking spaces. In future, cellular connections made over the 5G network will open up V2X possibilities beyond simply providing a “second opinion” for a vehicle’s local ADAS sensors, enabling a collective perception paradigm in driverless vehicles, adding to the safety and efficiency of smart mobility. Indeed, network operators have already begun discussing the “automotive slice” of the 5G network, which will provide the necessary quality of service in terms of latency, bandwidth and security to enable new use cases such as cooperative mobility and remote operation.
It is certainly true that network based connections over cellular infrastructure (LTE or 5G) are not unique to architectures featuring C-V2X. However, C-V2X has an evident strategic direction towards leveraging 5G NR’s ultra-reliable low latency communications and high data rates for both network-based and direct communications to support higher level of predictability and sensor sharing for autonomous driving, while ensuring backwards compatibility.
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A forthcoming ABI Research whitepaper will dive deeper into the developing applications for V2X technologies, the different adoption paradigms and the potential integrations that could be adopted over this horizon, as well the associated cost trends.
