# A Novel Opportunistic Network Routing Method on Campus Based on the Improved Markov Model
## 2 Related Works  
In opportunity networks, predicting node paths, managing caches reasonably, and reducing energy consumption have become research hotspots. Researchers at home and abroad have made many research results in related directions and proposed some solutions to the problems of path prediction and cache management in opportunity networks. [PERSON] et al. [7] proposed a social-based opportunistic routing algorithm, which only spreads the content when the social relationship between the next relay node and the destination node is closer than all previously encountered nodes and uses the social relationship to determine the most suitable node to forward the message, which significantly reduces the overhead in the message routing process. The routing method given in [8] used a secure routing protocol based on blockchain to design an integrated protocol, which can effectively protect data security. This routing method can effectively prevent eavesdropping, camouflage, wormholes, black holes, and fabrication attacks. In [9], [PERSON] et al. fully automated the routing process of opportunistic networks by using an iterative strategy algorithm, modeling the network environment as Markov decision processes, and using strategy iteration to solve the optimal strategy obtained by [PERSON] decision processes to optimize the routing process and maximize the possibility of message delivery. [PERSON] et al. [10] put forward an innovative routing strategy based on node activity, which considers the previous operation of the node on the message, calculates the confidence level of the node through the past behavior and activity of the node to determine whether it is a good candidate to forward a specific message and reduces the message dropping rate. [PERSON] et al. [11] presented a social network evolution analysis method based on triple, including a prediction algorithm and a quantization algorithm. The algorithm reduces the blindness of message forwarding and unnecessary waste of resources by predicting the connection probability between nodes in the network. [PERSON] et al. [12] put forward an algorithm combined with the sleep mechanism, which mainly solves the problem of judging the conditions of sleep state and wake-up time, forces the nodes in a low-energy state to sleep and avoids the nodes from consuming energy quickly. [PERSON] et al. [13] proposed a method based on a bitmap, which uses a routing tree based on the bitmap to find the path, and when the tree receives a request to send a message to a designated node, it directly sends a packet, which effectively improves the message delivery rate. [PERSON] et al. [14] studied an energy-efficient opportunistic routing protocol based on adaptive ranking. The residual energy and geographical location of nodes are used to calculate the level, and an efficient forwarding mode based on node level is determined, which improves the effective use of energy in the process of data transmission. [PERSON] et al. [15] proposed a method to minimize the consumption of network resources, using an epidemic diffusion model to evaluate the impact of message expiration time on message transmission, calculating the optimal expiration time and dynamically setting the expiration time, which significantly reduced the buffer usage and energy consumption. [PERSON] et al. [16] proposed the routing under an uncertain contact plan, extended the single copy routing in the Markov decision-making process to multiple copies, and used multiple copies to model the network state, which effectively improved the message delivery rate. [PERSON] et al. [17] used special monitoring nodes to check the behavior of other nodes and routed messages to nodes with sufficient residual energy levels, so that most of the forwarded messages are proportional to the energy level of the receiver, effectively solving the problem that nodes in the network are paralyzed due to energy consumption. [PERSON] et al. [18] proposed an improved hybrid routing protocol combining mobile ad hoc networks and latency-tolerant networks.