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LATEST NEWS
June 12, 2017
www.5GAA.org
Coexistence of C-V2X and 802.11p at 5.9 GHz
POSITION PAPER | 12 June 2017
1 Summary
Today the European market has interest in two distinct technologies for Intelligent Transport
Systems (ITS) and the provision of vehicle to vehicle communications; namely 3GPP LTE-V2X and
IEEE 802.11p.
The technology neutral nature of spectrum regulations in Europe means that both LTE-V2X
and
802.11p have equal rights to operate in the 5.9 GHz band, subject to compliance with the relevant
regulatory technical conditions.
It is not the objective of this paper to compare and contrast the relative merits of these two
technologies, although the 5GAA is a proponent of LTE-V2X as today’s realisation of Cellular V2X
(C-V2X), and as a platform to evolve towards 5G technologies.
Instead, in this paper we address the issue of co-channel coexistence between the two
technologies at 5.9 GHz. We note that this is a critically important issue for the ITS industry, and
that it is beneficial for all stakeholders to arrive at a proportionate, fair, and pragmatic solution to
resolve this matter, and allow the market to proceed with the deployment of ITS equipment.
To this end, we propose a solution – to be agreed among the stakeholders – to be implemented
in up to three steps. In all steps, each of C-V2X and 802.11p can operate safety-related ITS services
free from co-channel interference from the other technology. The difference between the distinct
steps lies in the overall usage efficiency of the spectrum resource: In the short-term, we propose
to allocate distinct 10 MHz channels at 5875-5905 MHz to each of the two technologies, while the
final configuration will apply full sharing of all available channels across the two technologies. The
latter will require further studies on appropriate sharing mechanisms and thus cannot be
provided from the beginning.
We further explain how such a first step
partitioning
of 5875-5905 MHz might be complemented
by additional technical mechanisms which would – where needed – allow each of C-V2X and
802.11p to access the remaining 20 MHz in a fair manner, with a reduced risk of harmful co-
channel interference.
We believe that the proposed approach would greatly facilitate the coexistence of C-V2X and
802.11p at 5.9 GHz, and we would encourage stakeholders to further develop this proposal and
come to a speedy agreement on this for the benefit of the European ITS industry as a whole.
LTE-V2X encompasses two interfaces: (a) The wide area network LTE interface (Uu) that connects end-user devices and vehicles
to base stations (eNBs) and the core network, to provide vehicle to network (V2N) services. LTE-V2N can be supported by
spectrum harmonised and designated for mobile communication networks; (b) The direct communications interface (PC5) that
connects vehicles to vehicles (V2V), to roadside infrastructure (V2I) and to pedestrians (V2P), for the provision of low-latency and
high-reliability V2V/I/P services independently of any MNO relationship and cellular network availability. LTE-V2V/I/P can be
supported by spectrum that is harmonised for ITS, namely 5.9 GHz in Europe. The direct communication mode does not require
coverage by a cellular network, or a V2N connection.