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- Towards a hardware-in-the-loop quantum optical ground station simulator and testbedPublication . Niehus, Manfred; Simão, José; Silva, João Castanheira da; Serrador, António; Carvalho, João M.; Gonçalves Cavaco Mendes, Mário JoséA single pass Bennett-Brassard 1984 protocol quantum key distribution downlink from a small quantum satellite in low earth orbit to an optical ground station is studied with the objective to develop the framework for a hardware-in-the-loop quantum optical ground station simulator and testbed.
- Powerless sensor for non-intrusive multi-fiber traffic monitoringPublication . Serrador, António; André, SérgioThe rapid expansion of fiber optic networks and services, which sees a large number of circuits enabled and disabled each day, introduces a significant complexity for operators to identify fibers that have and do not have attached clients. The service level agreements prevent operators from disconnecting circuits without absolute assurance that no clients are attached. We propose a non-intrusive multichannel fiber detector to facilitate the operation and maintenance of the optical networks. The optical distribution frame usually does not have any power available, thus, the proposed device operates without batteries and is powered by near field communication (NFC). Device installation does not require fiber disconnection or communication interruption, and introduces less than 1 dB insertion loss to detect optical signals down to -30 dBm. In order to read multiple fiber channel status, an NFC-enabled smartphone is used to power the device and measure the signal levels of each channel.
- A performance measurement platform for C-ITS over 5GPublication . Serrador, António; Mendes, Carlos; Datia, Nuno; Cota, Nuno; Cruz, Nuno; Beire, Ana R.This paper aims to present a new performance measurement tool dedicated to mobile cellular networks, focussed on the new C-ITS applications and challenges. Called ISEL QoS-Network Performance Evaluation (IQ-NPE), developed under the European Union 5G-MOBIX project, it is a measurement performance tool that is able to extract a wide range of performance parameters at different levels: radio, network layers and application. This is a step further when comparing with classical tools, based on mobile terminals, because C-ITS applications take advantage of cellular modems using Multiple Input Multiple Output (MIMO) advanced systems, due to available space offered by vehicles. IQ-NPE is designed to test classical alongside with the new C-ITS applications (ITS-G5 based) performance running at the Multi-access/Mobile Edge Computing (MEC) node in the new 5G architecture. All the collected data can be exported, as integrated performance data, to further be analysed using business intelligence tools. Thus, this paper presents the IQ-NPE general architecture, its main components, probes (units composed by hardware and software subsystems), together with configuration input and output examples.
- Public mobile wideband networks interference impact assessment on railways GSM-R networkPublication . Rouco, André; Cota, Nuno; Beire, Ana Rita; Serrador, AntónioThis paper presents a field study relating to the impact that public operator cellular networks such as UMTS (Universal Mobile Telecommunication System), LTE (Long-Term Evolution), and 5G-NR (5G - New Radio) have on railway GSM-R (Global System for Mobile Communications – Railway) networks. The validation of the interference calculation relied on actual network measurements taken along railway lines using a dedicated probe. Emissions from public networks, in some scenarios, have been shown to affect GSM-R networks to a large extent. The developed algorithm is currently being used in real GSM-R network planning to mitigate this negative effect on base station coverage and service performance.