# An Aquatic Mobile Sensing USV Swarm with a Link Quality-Based Delay Tolerant Network
## 2 Related Work
### Simulation  
There are several simulators for networking, and for robotics. [PERSON] et al. [23] presented mOVERS, an emulator capable of recreating scalable vehicular scenarios of data gathering and content  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Name**} & \multirow{2}{*}{**Type**} & **Single/Multiple Copy** & **Replication Rate** & **Passive/Active Monitoring** \\ \hline Direct contact & Direct & S & N/A & N/A \\ \hline Epidemic & Flooding & M & Very high & N/A \\ \hline Drone-Quality Delay Tolerant & & & & \\ Routing Approach & Probabilistic & S/M & Medium & Hybrid \\ \hline Q-PRoPHET & Probabilistic & S/M & Medium & Passive with Overhearing \\ \hline QoN-BSW & Probabilistic & M & High & Active \\ \hline HPR & Probabilistic & N/A & N/A & Hybrid \\ \hline PAmuLQE & Probabilistic & S/M & Low/Medium & Passive \\ \hline \hline \end{tabular}
\end{table}
Table 1: Forwarding Strategies overview.  
distribution in vehicular networks. This emulator works with mobile Opportunistic VEhicular (mOVE), a DTN-based architecture supporting communications using IEEE 802.11p and Wireless Access in Vehicular Environments (WAVE), and IEEE 802.11a/b/g (Wi-Fi technology) developed in the Network Architectures and Protocols research group www.it.pt/Groups/Index/36, where each node is capable of storing a packet and forwards it when a neighbor is available. [PERSON] et al. [24] presented the Opportunistic Networking Environment (ONE) simulator specifically designed for evaluating DTN routing and application protocols. It uses movement models to create scenarios, and already includes six well-known routing protocols. Since these platforms do not support robotic and physical simulation, they do not allow testing path planning or control algorithms.  
Simulators for aquatic robotics are categorized in two areas: underwater and surface. The majority of the simulators developed lies on the underwater category, such as the open source SubSim [25], Neptune [26], IGW [27] and MVS [28].  
[PERSON] et al. [29] described a ROS and Gazebo based simulator, named _Kelpie_, for testing and debugging real hardware of aquatic robots, providing more accurate physics simulation and rendering quality by using the geometric meshes of the vehicle models instead of simple geometric shape. Kelpie also allows the simulation of Unmanned Aerial Vehicles (UAVs). [PERSON] et al. [30] described a framework for the simulation of multiple water surface vehicles operating simultaneously. This testing tool requires modules to be developed in C++. [PERSON] et al. [31] presented the _UUV Simulator_, which is an open source gazebo-based project, with several algorithms for Unnamed Underwater Vehicles (UUVs). This project implements design models, world models, sensor models, and control algorithms. It is a simulator that allows hydrodynamic constraints, multi-robot systems, and the integration of new modules. This package also integrates an extensive wikipedia on all the modules and tutorials to integrate new robots, worlds or other control algorithms. Because it is ROS and Gazebo based, it is easily replicated in a RaspberryPi with sensors, facilitating the translation from simulated code to the real scenario. Due to these aspects, this package was chosen for the development of a new ROS and Gazebo based simulator with a network module for Unnamed Surface Vehicles. An overview of the modules included in this package is depicted in Figure 1.