  5G has been designed to support applications such as connected and automated
driving. To this aim, 5G includes a highly flexible New Radio (NR) interface
that can be configured to utilize different subcarrier spacings (SCS), slot
durations, scheduling, and retransmissions mechanisms. This flexibility can be
exploited to support advanced V2X services with strict latency and reliability
requirements using V2N2V (Vehicle-to-Network-to-Vehicles) communications
instead of direct or sidelink V2V (Vehicle-to-Vehicle). To analyze this
possibility, this paper presents a novel analytical model that estimates the
latency of 5G at the radio network level. The model accounts for the use of
different numerologies (SCS, slot durations and Cyclic Prefixes), modulation
and coding schemes, full-slots or mini-slots, semi-static and dynamic
scheduling, different retransmission mechanisms, and broadcast/multicast or
unicast transmissions. The model has been used to first analyze the impact of
different 5G NR radio configurations on the latency. We then identify which
radio configurations and scenarios can 5G NR satisfy the latency and
reliability requirements of V2X services using V2N2V communications. This paper
considers cooperative lane changes as a case study. The results show that 5G
can support advanced V2X services at the radio network level using V2N2V
communications under certain conditions that depend on the radio configuration,
bandwidth, service requirements and cell traffic load.
