A fixed-point model for semi-persistent scheduling of vehicular safety messages

TL;DR

This paper develops an analytical fixed-point model to evaluate semi-persistent scheduling in vehicular safety communications, demonstrating its accuracy and the benefits of flexible resource selection in reducing delay.

Contribution

It introduces a fixed-point analytical model for semi-persistent scheduling in vehicular networks and validates it with simulations, highlighting trade-offs between delay and collision probability.

Findings

Analytical model accurately estimates collision probability and delay.

Flexible resource block selection reduces delay significantly.

Trade-off exists between delay reduction and collision probability.

Abstract

In this paper, we focus on the performance analysis of a semi-persistent scheduling scheme for vehicular safety communications, motivated by the Mode 4 medium access control protocol in 3GPP Release 14 for Cellular-V2X. An analytical model is built and a fixed point method is used to calculate the collision probability and average delay in both fully connected and partially connected cases under the assumption of perfect PHY performance. We use Monte Carlo simulation to verify the results obtained in the analytical model. The simulation results show that our analytical model can give a good estimation of the collision probability and average delay. We verify that a trade-off between delay and collision probability can be achieved with a flexible resource block selection. Monte Carlo simulation results show that with the flexible resource selection scheme average delay can be shortened significantly with only a small compromise in collision probability.