## 2 Related Works  
In recent years, researchers at home and abroad have fully studied and optimized routing protocols that meet the communication environment of wireless Ad Hoc networks based on their characteristics. The earliest innovative research on routing technology was mainly concentrated in the mid-1990s. The MANET research team composed of IETF mainly studied the design and standardization of routing protocols for wireless Ad Hoc networks [5]. These protocols can be categorized into reactive, proactive, and hybrid routing protocols. Representative routing protocols include Dynamic Source Routing (DSR) [6], Optimized Link State Routing (OLSR) [7], Destination Sequence Distance Vector (DSDV) [8], and Ad Hoc On-Demand Distance Vector (AODV) [9]. In the DSDV routing protocol, mobile nodes periodically broadcast their routing information to their neighbors. Each node is required to maintain their routing table. The AODV protocol finds routes using the route request packet, and the route is discovered when needed. Research has shown that AODV performs better than DSDV in packet delivery ratio, throughput, and routing overhead. The delay of AODV is greater than DSDV [10]. For real-time applications, AODV performs better than the DSDV routing protocol [11]. In addition, in urban rail transit scenarios, the trackside nodes are fixed, and trains run along the track. Compared to traditional wireless Ad Hoc network nodes, the communication between them is relatively fixed, and it is not necessary to use active routing protocols to obtain the routing tables of all nodes. Therefore, active routing protocols will incur a significant amount of unnecessary overhead in this scenario. Although the delay of the AODV routing protocol is higher than that of DSDV, the algorithm proposed in this article uses static configuration to pre-configure the routing table, eliminating the delay of route discovery. In summary, the AODV routing protocol has more advantages in urban rail application scenarios compared to active routing protocols such as DSDV. Therefore, this article proposes new improvements based on the AODV routing protocol. To continuously improve the performance of routing protocols and better adapt to the communication environment, a large number of studies have optimized routing protocols from different perspectives. Compared with the traditional AODV, the proposed improved protocol has advantages in terms of the packet delivery fraction, overhead, and route setup time. Many researchers have made improvements to classic protocols. [PERSON] et al. present an optimized protocol, called B-AODV, based on the shortage of routing finding and routing repair of AODV. In B-AODV, first, through a reverse request by sending BRREQ to replace RREP, it reduces the time of routing finding. Second, two hops IP recorded in control messages and the routing table can improve the rate of routing repair and reduce the time of routing finding [12]. [PERSON] et al. propose a new probabilistic approach that dynamically fine-tunes the rebroadcasting probability of a node for routing request packets (RREQs) according to the number of neighbor nodes. Their proposed approach demonstrates better performance than blind flooding, fixed probabilistic, and adjusted flooding approaches [13]. Ref. [14] presents a new fitness function (FFn) used in the Genetic Algorithm (GA) to obtain the optimized route from those routes offered by the Ad Hoc Ondemand Multipath Distance Vector (AOMDV) routing protocol. These protocols provide an optimization process to select the efficient routes that have the highest fitness values implementing the shortest route and less data traffic. Ref. [15] proposes a new dynamic relationship zone routing protocol (DRZRP) for Ad Hoc networks. In this protocol, each node in the network establishes a neighboring zone with a radius of \(\rho\) hops and activates a relationship zone according to the service request frequency and service hotspot condition.