# All about Delay-Tolerant Networking (DTN) Contributions to Future Internet
## 3 Related Work
### Internet of Things and Smart Cities
#### 3.3.2 IoT and Smart Cities Applications  
Regarding the DTN suit and its applications in the IoT and smart city domains, some highlighted research areas focus on the following:  
* _Remote Environmental Monitoring:_ The process of collecting data on various environmental parameters in areas that are difficult to access or far from settlements. Delay-Tolerant Wireless Sensor Networks (DTWSNs) have been established to assist with the collection of data, as well as the tracking and monitoring of animals. For instance, [122] describes the design of a GPS tracking device that utilizes the DTN suite in order to monitor, collect data, and track the Galapagos pink land isiana.
* _Data Aggregation and Data Collection:_ The collection and integration of dispersed data points from various sources into a central system for analysis and decision making frequently address challenges related to limited connectivity. A typical example is the usage of DTN on Wireless Body Area Networks (WBANs), which are used in a plethora of scenarios, such as hospital data, military situations, and in the recognition of dangerous diseases for animals, as mentioned in [123]. Furthermore, DTN assists in data collection from Vehicular Delay-Tolerant Networks (VDTNs), particularly in applications for smart cities. An example is the Data Collection for Low Energy Devices (DC4 LED), which is a hierarchical VDTN routing tested in the city of Helsinki [124].
* _Disaster Management and Emergency Reports:_ Aim to address issues related to natural or man-made disasters. Typical examples are the utilization of the DTN protocols to ensure effective communication for the prioritization of messages in disaster scenarios [125], the organization of recovery operations in areas with limited network availability, and in proactive disaster management applications to predict patterns of human and vehicle mobility [126; 127].
* _Healthcare Monitoring in Rural Areas:_ Leveraging solutions to remotely monitor and manage patients' health, particularly in regions with limited access to medical facilities and health professionals. Such a delay-tolerant data communication system for thetransmission of health and environmental data to areas of developing countries is presented in [87].
* _Public Transportation and Mobility:_ The provision of common transport services facilitate efficient movement in both urban and rural areas, thereby improving accessibility and reducing congestion. An example of DTN application in this domain is the DTN routing algorithm as presented in [128].
* _Energy Management:_ The efficient use, monitoring, and optimization of energy resources to minimize consumption, reduce costs, and mitigate environmental impact. A combination of energy-efficient architectures is provided by [129] and evaluated in the ONE simulation.
* _Location Monitoring:_ The Real-Time Location System (RTLS) is a technology that tracks and identifies the current geographic location of objects or people in real time. RTLS is integrated in IoT cases, thereby allowing for the monitoring of the environmental and health conditions of workers. In underground scenarios such as miners' reconnaissance, RTLS plays a crucial role in location monitoring, as discussed in [130]. Additionally, the proposed architecture includes Bluetooth Low-Energy (BLE) beacon-based devices, while it also analyzes key factors for a future 6G IoT system.