MessageBased Communication for Heterogeneous Internet of Things Systems The Internet of Things (IoT) domain presents a wide spectrum of technologies for building IoT applications. The requirements are varying from one application to another granting uniqueness to each IoT system. Each application demands custom implementations to achieve efficient, secure and costeffective environments. They pose a set of properties that cannot be addressed by a singlebased protocol IoT network. Such properties are achievable by designing a heterogeneous IoT system, which integrates diverse IoT protocols and provides a network management solution to efficiently manage the system components. This paper proposes an IoT messagebased communication model applied atop the IoT protocols in order to achieve functional scalability and network management transparency agnostic to the employed communication protocol. The paper evaluates the proposed communication model and proves its functional scalability in a heterogeneous IoT system. The experimental assessment compares the payload size of the proposed system with respect to the LwM2M standard, a protocol designed specifically for IoT applications. In addition, the paper discusses the energy consumption introduced by the proposed model as well as the options available to reduce such impact.

IoT Protocols for Lowpower Massive IoT: A Communication Perspective The constantly growing number of resourcelimited MTC (MachineType Communication) devices is challenging both the telecommunication operators as well as industrial companies to efficiently design communication technologies, protocols, and enddevices for data transmissions in the upcoming 5G and beyond wireless communication networks. As the communication technologies for mMTC (massive Machine Type Communications)massive IoT (Internet of Things) attracted significant attention over the past years due to the extended communication range and improved lifetime of batteryoperated devices, the debate turned from the communication parameters of available LowPower WideArea (LPWA) technologies towards the implementation issues related to efficient data transmissions with respect to certain level of Quality of Service (QoS). In this regard, this paper aims to analyze already introduced communication protocols (i.e., TCP, UDP, CoAP (Constrained Application Protocol), and MQTT (Message Queuing Telemetry Transport)) possible to use for data transmission in massive IoT scenarios. Along with the highlights of the protocols in question, a practical implementation is done using the emerging cellular IoT standard, namely, NBIoT (Narrowband IoT). Out of the obtained data, the focus is primarily given to the sidebyside comparison of protocolsxe2x80x99 overheads and the subsequent data usage as the amount of transmitted data is deriving the monthly fees.