# Development, Implementation and Evaluation of An Epidemic Communication System
## 2 Related Works and Issues  
Epidemic communication differs from conventional mobile communication systems in that it is an ad hoc network based on multi-hop transmission, similar to a mobile communication network without any infrastructure. Multi-hop transmission involves communication through a connected multi-hop wireless route between the source and destination nodes. With epidemic communication, this is further adapted by enabling direct wireless communication between mobile nodes, and spatially spreading information through their movement. That is, epidemic communication utilizes a technique known as information floating, in which direct wireless communication is allowed only in specific regions, thereby preventing uncontrolled information diffusion while conveying information to unspecified nodes in the designated area [7, 8]. These methods leverage the capability of exchanging information between moving entities and disseminating information through their movement, making them suitable communication techniques for autonomously moving nodes, such as robots and drones. Figure 2 illustrates the operation. Nodes with information data  
Figure 1: Examples of autonomous networks with robots. (transmitting nodes) move consistently while retaining the data. If communication-capable nodes are in the vicinity of other nodes after moving, these nodes become the receiving nodes, and the transmitting nodes send data to them. Subsequently, the receiving nodes that receive the information then move, and upon encountering another node, repeat the transmission process. In essence, nodes carry and disseminate information, spreading it like an infection through repeated transfers. The advantage of using epidemic communication for such flower searches is that information data can be collected even in complex flight environments. For example, if there are obstacles such as leaves or stems, direct communication may not be able to transmit properly due to interference or diffraction. However, with epidemic communication, multiple drones can relay information data in such a way that they can avoid the obstacles and go around them, thus creating dynamic and flexible networks. Epidemic communication faces the following challenges. 1. Numerous theoretical studies have been conducted and various technical applications have been proposed. However, few examples of actual system implementations have been realized. The requirement for wireless devices with various functions such as relaying, connecting, disconnecting, and storing data is a challenge for construction of these systems. 2. The designs of actual communication systems are difficult to optimize with respect to specific communication distances and interferences between radio stations. In addition, the amount of data that can be transmitted must be calculated when nodes pass each other. 3. The system is assumed to be unsuitable from the viewpoint of information security for communications that may include personal information, such as handheld tablets, and few systems have been used practically or commercialized because of such problems. That is, no dedicated device has been developed because establishing it as a service is difficult. The challenges in (A) have been actively addressed using various methods, and intensive theoretical analyses have been conducted. For example, diverse approaches have been proposed for theoretical analysis. For the infection method, efforts have been made to reduce the duplication of infection instances of information data, thereby reducing the amount of information data held by each node. Additionally, the use of vaccine data has been explored to analyze the spread rate of infection and recovery [10]. The theoretical analysis of infection utilizes Markov chain models, and evaluations under various conditions have been conducted by modifying the parameters. Moreover, in [11], epidemic communication algorithms were evaluated by comparing gossip and push algorithms.