Coexistence of C-V2X and 802.11p at 5.9 GHz
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-V2X1 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.