With the LTE-V2X (LTE vehicle-to-everything) standard finalized and 5G standardization impending, the use of cellular technology for low-latency Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure (V2I) (combined, C-V2X, earlier post) applications is now a realistic prospect—one that will challenge the legacy IEEE 802.11p Dedicated Short-Range Communications (DSRC) standard.
In its new Intelligent Transportation Systems report, ABI Research notes that autonomous level 4 and driverless level 5 vehicles will require V2V and V2I capabilities to achieve ultra-high reliability levels; carriers such as Deutsche Telekom, Orange, SK Telecom, Telefonica, and Vodafone already performing trials on automotive 4G and/or 5G use cases.
The evolutionary path offered by cellular technologies and their large supporting mobile ecosystem is an attractive option for automotive suppliers and OEMs eager to execute early implementations of autonomous functionality. While cellular antagonists claim DSRC is more mature, reliable, secure, and ready to deploy, it remains to be seen whether it will survive the onslaught of the cellular ecosystem or continue to coexist with future cellular alternatives.—Dominique Bonte, Managing Director and Vice President at ABI Research
The legacy IEEE 802.11p/DSRC standard allows reliable low latency communication of basic safety messages between vehicles and between vehicles and roadside infrastructure. 802.11p (also known as Wireless Access in Vehicular Environment, WAVE) is an approved amendment of 802.11—the basis for Wi-Fi—specifically adding access in vehicle environments.
The US Federal Communication Commission (FCC) earlier allocated 75MHz of Dedicated Short Range Communications (DSRC) spectrum at 5.9 GHz to be used exclusively for vehicle-to-vehicle and infrastructure-to-vehicle communications. IEEE 802.11p allows the use of the 5.9 GHz band with channel spacing equal to 20MHz, 10MHz and 5MHz and lays down the requirements for using this band in Europe and US.
However, Part of Release 14 of the global 3GPP cellular standard (earlier post) introduced cellular V2X (C-V2X). C-V2X enhances LTE Direct for V2X direct communications, with improvements over 802.11p including up to a few additional seconds of alert latency and 2x the range. It also provides a roadmap towards 5G.
While a DSRC mandate seems imminent in the US, ABI Research expects cellular V2X to show steady growth, initially through LTE-V2X, reaching 300 million global subscriptions by 2030. At that point, 5G V2X will surpass it. Longer term, automotive OEMs will start to offer network-based low-latency, end-to-end automotive services.
The main challenge for cellular V2X is to get hold of dedicated spectrum needed for the Device-to-Device, or D2D, V2V protocol. While the intelligent transportation systems spectrum in the 5.9 GHz band was made available in the US, Europe, and other regions more than a decade ago, it remains reserved for DSRC. But this could change if, or more likely when, cellular giants like Ericsson, Qualcomm, and Samsung, unite and fight for lobbying power.—Dominique Bonte