Mitigating Latency Inflation in V2C Transactions Using Periodic Sidelink Communication

In the vehicle-to-cloud (V2C) interactions using 3GPP sidelink, vehicles transmit data to a server on the Internet and receive responses in return. This paper shows through real-life measurement that bi-directional end-to-end communication latency in V2C can be dominated by that caused by sidelink communication if the application data arrivals and the sidelink transmit resources are not synchronized. It is counter to our expectation that the delay on the non-sidelink leg that spans the 5G RAN, 5G core network, and the Internet will account for the majority of the latency. For reducing inflated latency on the sidelink, this paper explores several solution approaches: reduced selection window size, decreased packet delay budget, and adaptive selection window postponement. Through real-life measurements, we show that such measures can slash sidelink latency inflation by more than 50% so that 5G V2X sidelink can be more easily applied to real-time applications built on V2C communication.