5G V2X Architecture and Radio Aspects

A3GPP standardization is evolving beyond 5G the New Radio air interface (NR-Uu) framework defined in 3GPP Release 15 (also known as 5G phase 1) to study the support of advanced vehicle to everything (V2X) services. The NR Sidelink (SL) being designed in 3GPP Release 16 (5G phase 2) to support advanced V2X services directly between vehicles and other road users is expected to finish by the end of 2019. The advanced V2X services primarily focuses on platooning, advanced driving, extended sensor and remote driving use-cases. Supporting an end-to-end latency of 3ms and high reliability up-to 99.999% requirement requires substantial improvements in the air-interface design. Long Term Evolution (4G LTE) V2X sidelink supports the delivery of Basic Safety Messages to nearby V2X User Equipments (UE, the mobile device), hence the sidelink physical layer and the higher protocol layers are designed to support only broadcast type traffic without Hybrid Automatic Repeat Request (HARQ) feedback. With the advanced V2X service requirement, NR sidelink design should study V2X message delivery for different cast types such as unicast, groupcast and broadcast type traffics that requires substantial changes starting in V2X Release 16 network architecture, physical and protocol layers. This paper provides insights on the current Release 16 NR sidelink design for V2X. The network architecture enhancement discusses supporting flow-based Quality of Service (QoS) model for NR sidelink and the newly introduced network entities such as Network Data Analytics Function (NWDAF) providing QoS analytic. The design of the NR sidelink physical layer based on the Cyclic-Prefix Orthogonal Frequency-Division Multiplexing (CPOFDM) waveform addresses the necessary improvements needed in the sidelink procedures for reliable packet transmissions in a certain communication range. The protocol layer introduces a new overlapping zone concept to study both about HARQ feedback in a communication range and the resource segregation.