Page 47 - ITU Journal Future and evolving technologies Volume 3 (2022), Issue 2 – Towards vehicular networks in the 6G era

ITU Journal on Future and Evolving Technologies, Volume 3 (2022), Issue 2

CONTROLLED MOBILITY FOR C-V2X ROAD SAFETY RECEPTION OPTIMIZATION
Jingxuan Men , Yun Hou
1
2
1,2 Department of Computing, The Hang Seng University of Hong Kong, Hong Kong, China
NOTE: Corresponding author: Yun Hou, aileenhou@hsu.edu.hk

Abstract – The use case of the Cellular Vehicle-to-everything (C-V2X) for road safety requires real-time
network connection and information exchange between vehicles. In order to improve the reliability and
safety of the system, intelligent networked vehicles need to move cooperatively to achieve network
optimization. In this paper, we use C-V2X sidelink mode 4 abstraction and the regression results of C-V2X
network level simulation to formulate the optimization of the Packet Reception Rate (PRR) with fairness in
the road safety scenario. Under the optimization framework, we have designed a controlled mobility
algorithm for the transmission node to adaptively adjust its position to maximize the aggregated PRR using
only one-hop information. The simulation results show that the algorithm converges and improves the
average utility by 15% while providing fairness across receivers for C-V2X mode broadcast messages.

Keywords – Controlled mobility, network optimization, road safety, trajectory, vehicular
communications

1. INTRODUCTION packet loss rate, and a higher data rate [2-3]. Due to
the limitations of DSRC performance, C-V2X became
In the 5G and future 6G era, everything will be the more up-to-date standard for V2X and is
connected through the Internet. However, currently recognized and deployed across the world.
communication between vehicles is more C-V2X defines two communication modes for
challenging than general mobile communications vehicle applications: Base station coordinated Mode
due to fast mobility and high safety requirements. 3 and Autonomous Mode 4. In Mode 3, base stations
Vehicle-to-everything (V2X) communication is served as the control center to provide a scheduling
designed to expand vehicles’ sensing ranges beyond control message for vehicles within the coverage of
the one-hop sensing system provided by the on-car a cellular network. After receiving the control
camera, radar or lidar. V2X can be regarded as a message, the vehicles exchange data information
solution of wireless sensor systems [1], which with others through the PC5 interface according to
allows vehicles to share information with each the instructions from the base station. In Mode 4,
other through communication channels. It can the vehicles can operate without cellular network
detect hidden threats, expand the sensing range of coverage. Carrier sensing and Semi-Persistent
autonomous driving, and predict what will happen Scheduling (SPS) procedures are adopted for
next to further improve the safety, efficiency, and transmission to avoid potential packet collision
comfort of autonomous driving. Therefore, V2X is without the assistance of base stations. Road safety
considered to be the key to improving the safety of is one of the major use cases supported by C-V2X,
autonomous driving. When the intelligent and broadcast is used to cover as many as possible
connected vehicle communicates with another vehicles in the neighborhood.
vehicle, we call it the communication between
vehicles (V2V), while when the intelligent This paper mainly focuses on the C-V2X road safety
connected vehicle communicates with roadside use cases, where the status update and warning
units, traffic lights, road signs, etc., we call it the messages are periodically broadcast. In this case,
communication between vehicles and the per-node Packet Reception Rate (PRR), which is
infrastructures (V2I). defined as the ratio between the number of
neighboring vehicles with successful reception and
In the early days, Dedicated Short Range the total number of neighboring vehicles, is the
Communication (DSRC) and Cellular-V2X are two main objective to maximize for a C-V2X network. In
main standards to implement vehicular this paper, we study the influence of vehicles’ geo-
communications. However, compared with DSRC, C- location on PRR, and propose an algorithm to
V2X can support a longer communication distance, optimize the PRR with fairness between neighbors
better performance on NLOS conditions, lower

© International Telecommunication Union, 2022 35