Πλοήγηση ανά Συγγραφέας "Kamaratakis, Georgios"

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    Machine-to-machine (M2M) communication using MQTT-SN over an heterogeneous WSN infrastructure
    (ΕΛ.ΜΕ.ΠΑ., Σχολή Μηχανικών (ΣΜΗΧ), ΠΜΣ Πληροφορική και Πολυμέσα, 2024-01-25) Kamaratakis, Georgios; Καμαρατάκης, Γεώργιος
    The major protocols used for M2M communication are MQTT, CoAP, OMA LWM2M. In short, these protocols target devices that have to conserve power so that they can operate for a long time on batteries. In M2M/IoT protocols, the payload is very small compared to the internet protocols where the payload is heavy and the headers accordingly large. For a predefined, pre-planned WSN, the static allocation of sensor nodes and gateways is appropriate. The more sensor nodes we have, the more we need gateways to accomplish the whole scenario based on IoT. With the exception of very few TCP/IP based WSNs (e.g. WLAN), where IP addresses are used for addressing the nodes, most WSNs adopt their own addressing scheme to accomplish inter-nodal communication. This feature makes the sensor networks complicated to expand and to interact with other WSN of different technology or the rest of the TCP/IP world. To this end, we can make use of MQTT protocol. MQ Telemetry Transport (MQTT) is an open source publish/subscribe messaging protocol designed for power constrained devices and low-bandwidth, high-latency networks. MQTT creates multicast groups of subscribers based on the so-called “topics” they are registered to, and by that way the issue of communication between heterogeneous networking infrastructures can be solved at Application Layer. However, MQTT is TCP/IP based. For a successful MQTT implementation there is the need of an intermediate broker keeping TCP sockets alive for continuous submission & receipt of data with the nodes participating in each Topic. This constrains its applications to TCP/IP-based WSNs. In this scope, the MQTT-SN (MQTT for Sensor Networks) protocol has been proposed. MQTT-SN is an optimized version of MQTT, designed specifically for efficient operation in large low-power IoT Sensor Networks (SN). It uses the same publish/subscribe model and hence it can be considered as a version of MQTT. However, it uses UDP as the transport protocol and introduces MQTT-SN Gateways as intermediaries between different WSNs. Currently, very few deployments of MQTT-SN exist. Aim of this thesis is to: a) Investigate how we can interconnect various WSN and achieve a common communication infrastructure by implementing MQTT-SN, b) study the evaluation tests of this implementation, c) develop a system that can easily fit any heterogeneous IoT deployment. In general, we are interested in confirming the results by other researchers concerning MQTT-SN for better performance.