## 1 Introduction
### Motivation and Objectives  
Bandwidth efficiency of a V2X network assisted by UAVs and MBSs has been analyzed recently in [26], where V-N is allowed to transmit and communicate their data to the desired V-N via V-N to V-N transmissions, V-N to MBS transmissions, or V-N to UAV transmissions. However, the influence of jamming devices over UAV-assisted C-V2X communications is not analyzed, and also the effect of UAV's beam-width variation operating in the millimeter-wave frequency band is not investigated. Moreover, the bandwidth efficiency of each of the V-N connections, like V2V connections, V2M (i.e., V-N to MBS) connections, V2L (i.e., V-N to LOS UAV) connections, and V2N (i.e., V-N to NLOS UAV) connections, with beam-width fluctuations and multiple jamming clusters, is not analyzed. Motivated by this research gap, we evaluate the effectiveness of UAV-assisted C-V2X communications with jamming devices operating at the millimeter-wave frequency band and also analyze the influence of beam-width variations, along with clustered jamming, over V-N connections, e.g., V2V connections, V2M connections, V2L connections, and V2N connections. Our work is different than the state-of-the-art in the following:  
1. The work presented in [11] considers a C-V2X network that evaluates the association probability, coverage probability, and rate performance of the V-N. However, our investigated system considers a UAV-assisted C-V2X network that leverages UAVs and MBSs by considering a millimeter-wave antenna and evaluates association, coverage, and SE of the V-N.
2. The work presented in [16] considers a UAV-assisted cellular network that leverages LOS UAVs, NLOS UAVs, and MBSs. However, the work does not consider vehicular communications in the presence of jammers. Our method evaluates UAV-assisted C-V2X communications, exploiting jamming and millimeter-wave antennas. 3. The work presented in [26] considers UAV-assisted C-V2X communications and evaluates bandwidth efficiency. However, the work does not consider jamming interference as well as 3D beamforming millimeter-wave antennas. Our analysis considers millimeter-wave antennas for UAV-assisted C-V2X communications by exploiting clustered jamming and evaluates association probability, coverage probability, and SE of the network. Also, our setup investigates the effect of 3D antenna beam-width variations on the system's efficiency. The novelty of our proposed method lies in the way we develop our model's framework that considers multiple V-Ns distributed along multiple roads randomly, and V-Ns are allowed to communicate with the recipient V-Ns either by utilizing infrastructure (such as LOS UAVs, NLOS UAVs, and MBSs) or without utilizing infrastructure (such as in V-N to V-N communications), which has not been evaluated in the previous literature. Moreover, our proposed setup considers the impact of clustered jamming on V-N links, such as V-N to V-N links, V2M links, V2L links, and V2N links. Also, the influence of 3D beam-width variations along with the clustered jamming is analyzed on the network's efficiency. The primary contributions of our paper are given in the following:  
* A framework for a UAV-assisted C-V2X network, which considers jammers and beam variations, is presented. * The performance of V2V, V2M, V2L, and V2N connections, considering clustered jamming, is evaluated in terms of coverage and SE by varying network parameters such as the number of V-Ns, MBSs, and LAPs. * Analytical equations for the association and coverage of V2V, V2M, V2L, and V2N connections, along with the clustered jamming devices, are derived. * The outcomes demonstrate that the effectiveness of UAV-assisted C-V2X transmissions is severely degraded in a network that is exploited by jamming and beam variations. The rest of the article is described in the following: A UAV-assisted C-V2X system exploited by jammers is modeled in Section 2. The distance distributions for base stations, UAVs, and V-Ns are described in Section 3.