# Routing Enhancement in MANET Using Particle Swarm Algorithm
## 1 Introduction  
With the development of wireless networks, one of the most prominent areas of research in the modern era is MANETs. Mobile ad hoc Networks (MANETs) are some of the most popular wireless communication networks, consisting of multiple mobile nodes interacting with other nodes using a decentralized infrastructure [1]. This type of network does not rely on a fixed infrastructure. It is highly adoptable in challenging environments, such as emergency management, disaster recovery, border facility sensors, and vehicle networks. Through MANET [2], users can send data without following a definite structure. Furthermore, it is necessary to have an impermanent network with no centralized management or communication structure. During data packet transmission, each node in MANET performs the roles of host and router. Additionally, it has a dynamic topology, and each node has mobility behaviors. Each node is self-configuring and self-healing without the need for human intervention [3]. The mobility nature of MANETs results in constant and unpredictable changes in network topology, leading to complex routing operations [4]. The routing protocol for MANETs contains a routing algorithm with defined rules that are used to monitor the network's operation.  
MANET routing protocols are categorized into (i) proactive, (ii) reactive, and (iii) hybrid protocols [5]. In the proactive or Table-driven protocol, each node keeps track of one or more routing tables containing information about the network topology [6]. The reactive protocol depends on the query-reply dialog principle. It does not conserve the up-to-date topology but initiates the process only when a routing path needs to be discovered. The hybrid routing protocol integrates both reactive and proactive routing protocols by dividing the network into zones. The proactive protocol is used when both the source and destination are in the same zone. There are several issues with the routing protocolsthat are used in MANETs [7]. Proactive routing, initially, reduces the network's actual data communication capacity. A significant amount of routing table data is exchanged, which takes a lot of the network's capacity as mobile nodes continuously update their routing tables. Moreover, it does not work for large networks since the entries in the routing become too large. Applications that use real-time data and multimedia communication are not proper in on-demand hybrid routing protocols. Hybrid routing protocols are more complex, difficult to configure, and require more memory and processing power.  
Traditional routing protocols cannot overcome challenges in MANET because of its limited energy resources, changing topology, and limited link capacity. When routing becomes a critical issue in a challenging network scenario and conventional routing strategies break down, SI is an appealing solution. SI involves a group of agents that interact with each other and with their surroundings [8]. Particle Swarm Optimization (PSO) is an effective optimization technique that relies on mobility and swarm intelligence [9]. It employs agents to spread out in the search area to locate the optimal solution. Particles adjust their positions based on their own experiences and the experiences of other particles. PSO evaluates each particle using a fitness function to determine the position that provides the best evaluation of the fitness function.  
In this paper, we propose an EPSO algorithm to find the best routing path in MANETs. It uses a modified fitness function that takes into account the distance, energy consumption, and delay of the network. These modifications are aimed at improving the MANET performance. In this paper, a literature review is provided in Section 2. The EPSO algorithm is presented in Section 3. Evaluation metrics, simulation results, an ablation study, and an analysis of the EPSO are given in Sections 4, 5, and 6, respectively. Section 7 concludes the paper.