# Weight-Based PA-GPSR Protocol Improvement Method in VANET
## 1 Introduction  
As the number of automobiles in the world continues to increase, countries around are also paying ever-more attention to traffic congestion and accidents. The intelligent transport system (ITS) proposed to effectively improve traffic efficiency plays an extremely important role in the mobility of today's digital world [1]. VANET is a special kind of mobile ad hoc network (MANET), which is widely used in the transportation field and has become an important part of ITS [2, 3]. With the rapid growth in network technology, computing power, and storage resources, VANET has become a network with continuous self-configuration and no infrastructure characteristics [4]. VANET can provide onboard services, such as information about traffic, road accidents, weather conditions, and general traffic warnings [5, 6]. Vehicles that have encountered a road accident can broadcast news about this incident. Other vehicles can change their driving routes in advance to avoid possible traffic jams or other accidents, thereby improving the driving experience and safety. Each vehicle in VANET is equipped with an onboard unit (OBU), which is a built-in onboard network device that can share real-time traffic-related information with surrounding vehicles and distributed roadside units (RSU) [7]. The communication modes in VANETcan be divided into vehicle-to-vehicle (V2V) and vehicle-to-infrastructure communication (V2I) [8; 9]. Due to the cost of installing RSU, it is not feasible to use a large number of RSUs to provide the entire network connection. Reliable routing schemes can be used to improve the efficiency of data dissemination in a V2V environment. The routing protocol is an important part of VANET, and its performance directly determines the efficiency of VANET. However, due to the continuous changes in the network topology and the mobility of vehicle nodes, the success rate of data packet transmission cannot be guaranteed, resulting in the routing protocol previously applicable to MANET being no longer applicable to VANET [10; 11]. As there is no need to maintain any routing table or share connection status with neighbors, routing is only established when forwarding data packets. Geographic location-based routing protocols are considered more suitable for VANET [12; 13]. Since the global positioning system (GPS) is widely used in vehicles, the location of the vehicle can be easily obtained through periodic beacon. In summary, the existing location-based research improves the selection of optimal forwarding nodes in different ways. However, due to the high topology changes in VANET, these schemes will also encounter performance degradation problems. Given the complex characteristics and application requirements of sparse network scenarios in urban environments, this paper proposes a weight-based path-aware greedy peripheral stateless routing protocol (W-PAGPSR). In the routing establishment stage, based on the distance, direction, reliable node density, and cumulative communication duration, the greedy forwarding strategy is used to select the next hop node to reduce the problem of poor performance in sparse networks caused by frequent link interruptions and data retransmissions. In the routing maintenance stage, according to the left and right-hand rules, the data packet delivery angle and reliable node density are considered comprehensively, and the next hop node is selected using the perimeter forwarding strategy to improve the high delay caused by the routing loop. Finally, the data packet is delivered to the destination through multi-hop transmission, which achieves the effect of reducing end-to-end delay, increasing throughput, and improving the packet delivery rate. The main contributions of this paper are as follows:  
1. We improve the location-based routing protocol in VANET. 2.