Cooperative Relaying for URLLC in V2X Networks

Abstract

We characterize a two-phase transmission scheme for a vehicle-to-everything (V2X) network, designed for ultra-reliable low-latency communications (URLLC). In the proposed scheme, the user-plane latency period for the URLLC application is divided into two phases by a partitioning factor. First, we derive the signal to noise ratio (SNR) coverage probability of a test vehicular node in the network as a function of the partitioning factor. We also study the impact of interference on the system performance. We show that the proposed scheme performs better in terms of the service outage as compared to a broadcast-only protocol for small file sizes. On the contrary, resource partitioning proves detrimental for large file sizes. Then, for the noise-limited case, we study the trend of the optimal resource-partitioning factor with respect to the transmitted data-size and the density of the vehicular nodes in the network. This letter shows that the data-size has a larger impact on the information outage, as compared to the density of the vehicular nodes.