## 1 Introduction  
Vehicle to Everything (V2X) is a ubiquitous network that realizes a comprehensive interconnection of everything, from Vehicle to Vehicle (V2V), Vehicle to Infrastructure (V2I), Vehicle to Pedestrian (V2P) and Vehicle to Network (V2N) [1]. In the 5G network environment, the Internet of Vehicles involves five major elements: people, vehicles, roads, network connections and service platforms. Moreover, V2X is a complex heterogeneous network with rapid expansion of communication service data and coexistence of cellular network and Internet of Vehicles. Dedicated Short Range Communication (DSRC) and Cellular Vehicle to Everything (C-V2X) are the two main technical standards for V2X communication [2]. DSRC implements V2X communication through a series of communication protocols, including the IEEE 802.11p protocol and the IEEE 1609.1.4 protocol [3]. The former supports wireless access to the in-vehicle environment, while the latter supports network services and multi-channel operation. Moreover, DSRC can efficiently form dynamic in-vehicle networks that are better adapted to vehicle mobility characteristics, enabling dynamic and stable connections between fast-moving vehicles and roadside facilities. C-V2X is a cellular network-based in-vehicle communication technology proposed by the 3 GPP organization, which can realize vehicle communication with the help of cellular networks such as Long-Term Evolution (LTE) and 5G, and has the advantages of wide coverage, high capacity, low latency and high quality of service [4]. DSRC originated from the IEEE 802.11 standard, which was originally designed for low mobility wireless LANs with drawbacks such as a low data rate, limited coverage and a low quality of service. The IEEE802.11p protocol uses the Carrier Sense Multiple Access (CSMA) mechanism in congestion scenarios, which is prone to frequent collisions, leading to a sharp deterioration in network performance. Although the use of DSRC technology enables vehicles to form dynamic self-organizing networks, the high-speed mobility of nodes increases the instability of network topological connections, which affects functions such as routing and addressing [5], and further causes network congestion. In addition, there are many obstacles affecting the line-of-sight in cities, which greatly degrade the low DSRC communication performance [6], and the use of DSRC technology in some harsh driving environments entails significant safety risks. Some scholars have proposed the use of heterogeneous communication access technology combining DSRC and C-V2X in V2X networks to solve the problem that the communication process of V2X cannot adapt to high-speed mobility [7; 8; 9; 10]. With the increasing number of motor vehicles, roads are becoming more and more congested. When the density of vehicles within the communication range reaches a threshold value, congestion is easily triggered. At this time, frequent information collisions occur, making it impossible to broadcast safety information in a timely manner, and network performance deteriorates dramatically, leading to frequent traffic accidents. Therefore, how to solve congestion control in vehicle communications is a problem worthy of attention and research. Here, the Transmission Control Protocol (TCP), as the key technology of network congestion control, plays a crucial role in V2X. In addition, the variation trend of the size of the congestion window presents a law of similar normal distribution curve, which has a certain degree of local symmetry. The topology of heterogeneous V2X is complex. The high-speed mobility of vehicles and the dynamic nature of network topology make the distribution of computing resources uneven in several spatio-temporal dimensions such as communication traffic, channel information, node density and network environment.