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“the evaluation of the spectrum needs for
advanced use cases is not a trivial task”

Based on the results of our studies of the spectrum needs of C-V2X As the ITS industry develops further, and we begin to better
direct communications (V2V/I/P), we can draw the following understand the demands of advanced driver assistance and
conclusions: autonomous driving, we will assess the extent to which the 5.9 GHz
band (5850-5925 MHz) – which is globally harmonised for ITS by
a) We expect that the delivery of day-1 use cases via LTE-V2X for the ITU-R – is sufficient to meet the spectrum needs of the road
the support of basic safety ITS services will require between 10 and users, and whether additional spectrum designated for ITS will be
20 MHz of spectrum at 5.9 GHz for V2V/I communications.
required.
b) We expect that the delivery of advanced use cases via LTE-V2X
and NR-V2X for the support of advanced driving services will Furthermore, based on the results of our studies of the spectrum
require an additional 40 MHz or more of spectrum at 5.9 GHz for needs of C-V2X network-based (V2N) communications, we can
V2V/I/P communications. draw the following conclusions:
a) At least 50 MHz of additional service-agnostic low-band (< 1
The above conclusion with regards to advanced use cases deserves GHz) spectrum would be required for mobile operators to provide
some elaboration:
advanced automotive V2N services in rural environments with
• Some important advanced driving use cases (e.g. High-Definition affordable deployment costs.
Sensor Sharing) involve the ability of road users to share their b) At least 500 MHz of additional service-agnostic mid-band (1 to 7
processed sensor data with other road users on a continual GHz) spectrum would be required for mobile operators to provide
basis for what is known as cooperative perception, to provide high capacity city wide advanced automotive V2N services.
advanced driver assistance and to facilitate autonomous driving.
The appropriate amount of sensor data which should be shared In the above, the term “additional” means availability of spectrum
is an open question for the industry, and directly impacts the in addition to the bands that are currently identified for IMT use by
required spectrum. Our estimate of spectrum needs for these use mobile communication networks.
cases is 40 MHz or more depending on the extent of information The 5GAA places great value on the importance of V2N
sharing.
communications in enabling future advanced driving use cases, as
• Many other advanced driving use cases are event triggered supported by the Uu interface of C-V2X. Accordingly, the 5GAA
(e.g. Cooperative Manoeuvres), that is to say, messages are recommends that national and regional administrations ensure
exchanged over the air in response to a desire by a road user the availability of sufficient spectrum for mobile communication
to undertake a specific manoeuvre (e.g., changing lanes, joining networks in the so-called low-bands and mid-bands for the support
a freeway, crossing an intersection, or the like). Here, the road of services, including ITS, in the coming decade.
user shares its intended trajectory with other road users as part
of a handshake exchange of information, in order to provide It should be emphasised that unless otherwise stated the
advanced driver assistance and to facilitate autonomous driving. spectrum needs values estimated in this report are based on the
The contribution of event triggered use cases to the overall ITS assumption of a 100% penetration of ITS equipment among the
spectrum needs is stochastic, in the sense that such use cases population of road users. Furthermore, the characteristics of
may or may not occur at the same time, and this can result in a some advanced use cases, and the approach to their modelling
highly time variable demand for spectrum at any given location. are still under discussion. Finally, the 3GPP specifications on
C-V2X allow for a broad range of parameterisations, including
As a result, the evaluation of the spectrum needs for advanced use different trade-offs between reliability and redundancy levels (e.g.,
cases is not a trivial task. Nevertheless, it is clear that the 70-75 packet retransmissions optionally employing a two transmission
MHz of ITS spectrum in the 5.9 GHz band (as presently allocated time intervals mode); it should be noted that increased levels
in many regions and under consideration in other regions) is of redundancy will affect the spectrum needs requirements
needed to support the basic safety and advanced use cases under correspondingly. Refined spectrum needs estimates for these use
consideration today. Notably, it is the view of the 5GAA that the cases will be included in a future edition of this report.
choice of using LTE-V2X or NR-V2X in any given channel in the 5.9 https://5gaa.org
GHz band should be market-led. Like any emerging sector, there
could be unforeseen ITS use cases that would require even more
spectrum as the market evolves.
1 The 5GAA study of spectrum needs for safety related intelligent transportation systems – day 1 and advanced use cases can be accessed from the web site.
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