# Multi-Decision Dynamic Intelligent Routing Protocol for Delay-Tolerant Networks
## 1 Introduction  
Future wireless networks must continually evolve to adapt to changing wireless communication environments. In harsh and complex scenarios such as wilderness exploration and underwater sensor deployments, the high mobility of nodes leads to frequent changes in network topology, resulting in message loss or significant delays. Traditional routing protocols are often unreliable and ineffective in such circumstances. To facilitate networking and communication in these challenging environments, researchers have introduced a specialized network paradigm that relies on the mobility of nodes to relay information: Delay Tolerant Networks (DTNs) [1]. As an innovative communication approach, DTNs provide a new method to address the instability of connections in wireless networks. They no longer depend on the connectivity requirements of traditional networks but instead utilize cognitive data transmission between mobile nodes. In DTNs, traditional network connectivity requirements do not apply, as they rely on opportunistic encounters between mobile nodes for data transmission. This allows nodes to relay messages when they come into contact with each other, even in resource-constrained environments. Store-carry-forward routing [2] is one of the key mechanisms for addressing routing challenges in DTNs. If a node is not connected to other nodes, it stores messages in its buffer until another node enters its communication range. Once this occurs, the message is forwarded to that node, with the hope that intermediate nodes can relay the message to the destination node. Based on this concept, researchers have proposed various DTN routing protocols. DTN research focuses on the design of message routing and forwarding protocols, which play akey role in DTN message transmission. There are three main types of routing protocols: historical information-based routing protocols, community-based routing protocols, and reinforcement learning-based routing protocols. In history-based routing protocols, protocols utilize historical information about nodes to assess the probability of encounters between nodes, enabling the selection of the next-hop node for message forwarding. The Prophet protocol [3] calculates the probability of nodes encountering the destination node based on their historical information and uses this encounter probability as a utility value to evaluate the likelihood of successfully forwarding messages to the destination node. Ref. [4] proposes a privacy-preserving protocol for utility-based routing (PPUR) in Delay Tolerant Networks (DTNs). The protocol aims to address privacy concerns while optimizing routing decisions based on utility. Ref. [5] presents the Flooding and Forwarding History-Based Routing (FFHBR) algorithm, which determines the best relay node by analyzing the node encounter history and deciding whether to flood propagate the message or forward it directly to the target node. Ref. [6] proposed an Enhanced Message Replication Technique (EMRT) for DTN routing protocols, where EMRT dynamically adjusts the number of message replicas to minimize overhead and maximize the delivery rate based on encounter-based routing metrics, network congestion, and capacity. In terms of community attributes, ref. [7] proposes an opportunistic social network routing algorithm (UADT) based on user-adaptive data transmission that takes into account factors such as user preferences, social relationships, and network conditions to improve the efficiency and effectiveness of data transmission in opportunistic social networks. Ref. [8] introduces an adaptive multiple spray-and-wait routing algorithm based on social circles in delay-tolerant networks (DTNs). The algorithm dynamically adjusts the number of message copies sprayed based on the encounter history and social relationships between nodes. Ref. [9] presents a Hybrid Social-Based Routing (HSBR) protocol that utilizes social characteristics, such as community structure and social similarity, to make forwarding decisions. Ref.