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Projecte llegit

Títol: Development, validation and evaluation of an IoT application over CoAP and NTN NB-IoT

Estudiants que han llegit aquest projecte:

Director/a: GÓMEZ MONTENEGRO, CARLES

Departament: ENTEL

Títol: Development, validation and evaluation of an IoT application over CoAP and NTN NB-IoT

Data inici oferta: 22-01-2026     Data finalització oferta: 22-09-2026


Estudis d'assignació del projecte:
    DG ENG AERO/TELEMÀT
Tipus: Individual
 
Lloc de realització: EETAC
 
Paraules clau:
NTN NB-IoT, CoAP, satellite, IoT
 
Descripció del contingut i pla d'activitats:
Non-Terrestrial Networks (NTNs) are wireless communication systems that comprise flying or orbiting elements, such as drones or satellites, that provide network coverage. The high momentum of the satellite domain, especially in Low Earth Orbit (LEO) environments, is fueling the NTN field. One application of NTNs is providing connectivity to IoT devices. In this regard, the 3GPP has been developing NTN extensions for NarrowBand IoT (NB-IoT). On the other hand, for the sake of performance improvement, especially for energy-constrained IoT devices, it is important that upper-layer protocols also be efficient. At the application layer, the Constrained Application Protocol (CoAP) is a lightweight, IP-based web transfer protocol, designed for constrained-node networks, which are typical in IoT environments.

This project proposes the development, validation and evaluation of an IoT application over CoAP and NTN NB-IoT. The project will focus on the use of real endpoints (IoT device and server) running real implementations of CoAP and NTN NB-IoT. A complete testbed emulating satellite coverage conditions will be used. The feasibility of carrying out experiments with real satellite connectivity will be assessed. Performance evaluation will focus on parameters such as packet delivery ratio, latency, and energy consumption.
 
Overview (resum en anglès):
New applications for the Internet of Things (IoT), such as sensor networks, are implemented in extremely constrained devices, regarding both processing power and energy availability. In addition, devices are sometimes placed in remote locations and deployed in large numbers, making wired networks and power impractical. Non-Terrestrial Networks (NTN) have emerged as an alternative to ground-based cellular networks, providing satellite-based global coverage to IoT devices for a relatively low cost, while providing very high availability, being immune to extreme weather and natural disasters.

NarrowBand - Internet of Things (NB-IoT) has proven to be a valid access network for Low Earth Orbit satellites, in which the link budget is enough to serve small devices with regular hardware, such as that used for terrestrial networks. However, these orbits provide discontinuous coverage to users, raising the need to add Store & Forward mechanisms for user and signalling packets, which buffer data until the link becomes available. This mechanism increases the transmission delay of packets by several orders of magnitude, to Round-Trip Times (RTT) in the order of hours.

Application level protocols must also be adapted to constrained devices and networks. While the Hypertext Transfer Protocol (HTTP) is very widely used for Machine-to-Machine communications, it is very inefficient, as all headers are transmitted as text. Moreover, it is transported over the Transmission Control Protocol (TCP), which behaves poorly in high-delay networks. The Constrained Application Protocol (CoAP) is an alternative to HTTP with binary headers, providing a much better efficiency, and it can be transported over UDP.

This project assesses the suitability of using CoAP in NTN NB-IoT, with special emphasis on the energy consumption. A sample appliction matching a typical use case of the network is designed, and the consumption of sending various types of packets is compared. Tests have been made with raw UDP packets, with user data directly in them, CoAP NON packets (without confirmation), and CoAP CON (with confirmation). A mathematical model to predict the battery lifetime of devices is also developed, with various tunable parameters.

This project has concluded that using CoAP in a network with a high delay is perfectly feasible, although several considerations must be taken. Timers have to be adjusted, and the congestion control mechanism, although it can operate as it is, could be adapted to improve efficiency. The energy cost of adding an extra header to messages is almost negligible, and provides features that would need to be implemented anyway at a higher layer if CoAP were not used.

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