Study of the Impact of PHY and MAC Parameters in 3GPP C-V2V Mode 4

Abstract

In the latest years, 3GPP has added short-range cellular-vehicle-to-anything (C-V2X) to the features of LTE and 5G to allow vehicles, roadside devices, and vulnerable users to directly exchange information using the same chipset as for classical long-range connections. C-V2X is based on the use of advanced physical layer techniques and orthogonal resources, and one of the main aspects affecting its performance is the way resources are allocated. Allocations can be either managed by the network or in a distributed way, directly by the nodes. The latter case, called Mode 4, is required in those situations where the network cannot be involved in the scheduling process, for example due to a lack of coverage, but could also be adopted in order to reduce the processing burden of eNodeB. An algorithm, defined in the standards, makes nodes sense the medium and identify the best time-frequency combination to allocate their messages. Focusing on C-V2X Mode 4, in this work we analyse the parameters of the algorithm designed by 3GPP and their impact on the system performance. Through simulations in different large-scale scenarios, we show that modifying some parameters have negligible effect, that the proper choice of others can indeed improve the quality of service, and that a group of parameters allows to trade-off reliability with update delay. The provided results can also be exploited to guide future work. INDEX TERMS C-V2X, Intelligent vehicles, Vehicular and wireless technologies, Wireless networks

Congestion Control Mechanisms in IEEE 802.11p and Sidelink C-V2X

“…The noise figure is set to 9 dB. In the case of LTE-V2X, the keep probability adopted by Mode 4 is set to 0 in order to minimize the probability of consecutive collisions [15], [20]. A summary is provided in Table I.…”

Geo-Based Scheduling for C-V2X Networks

“…It is decremented by one after each packet transmission, and the vehicle must select with probability (1-P) new sub-channels when Reselection Counter is equal to zero. Following [8], P is configured in this study equal to 0.…”

“…Different studies have proposed options to improve the performance of C-V2X mode 4 and its SPS scheme. For example, [8]- [11] analyze and optimize the parameters of the SPS algorithm that are not fixed by the 3GPP standard. [12]- [15] propose modifications or extensions to the SPS algorithm but maintain most of its functionality.…”

Multiobjective optimization‐based radio resource allocation and sharing algorithm for D2D‐based V2V communication

“…In Mode 3, vehicles communicate directly between them, but the communications are performed by the cellular infrastructure that assigns the subchannels for every V2V communication. In Mode 4, vehicles autonomously select the subchannels or radio resources for their V2V transmission without the management of cellular infrastructure . These approaches have added new features and enhancements to vehicular networks.…”

“…In Mode 4, vehicles autonomously select the subchannels or radio resources for their V2V transmission without the management of cellular infrastructure. 8,9 These approaches have added new features and enhancements to vehicular networks.…”