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  • Battery lifetime estimation for LoRaWAN communications
    Publication . Fialho, Vitor; Fortes, Fernando
    Smart Cities concept increased the number of end devices (ED) which allow the acquisition of parameters for further analysis and processing. The actual technologies based on Internet of Things (IoT) enable sensors connectivity to Internet. This feature allows real time acquisition of several physical data important for smart cities monitoring. In order to minimize the power consumption, Low Power Wide Area Networks (LPWAN) assumes an important role on the evolution and growing of wireless network sensors. In this particular type of network, LoRaWAN has taken the lead, among other technologies. Typically most end devices need to be powered with batteries, since they are in remote zones. Therefore one important issue to consider is the global power consumption of the end device building blocks: LoRa transceiver, microcontroller unit and sensor unit. This paper presents the study and simulation results supported on LoRa modulation parameters, in order to estimate the battery lifetime, which is useful for IoT remote sensing units. The achieved results denote it is possible to configure LoRa transceiver with similar parameters and different payloads, reaching the same battery lifetime.
  • RF Receiver front end for 28.5 GHz applications on a 70 GHz F-T SiGe BiCMOS process
    Publication . Fortes, Fernando; Mahmoudi, Reza; Roermund, A.H.M. Van
    This article presents the design and test of a receiver front end aimed at LMDS applications at 28.5 GHz. It presents a system-level design after which the receiver was designed. The receiver comprises an LNA, quadrature mixer and quadrature local oscillator. Experimental results at 24 GHz center frequency show a conversion voltage gain of 15 dB and conversion noise figure of 14 5 dB. The receiver operates from a 2 5 V power supply with a total current consumption of 31 mA.