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Publications

Publications by CTM

2021

Reproducible MIMO operation in ns-3 using trace-based wi-fi rate adaptation

Authors
Lamela, V; Fontes, H; Ruela, J; Ricardo, M; Campos, R;

Publication
WNS3 2021: 2021 Workshop on ns-3, Virtual Event, USA

Abstract
Today, wireless networks are operating in increasingly complex environments, impacting the evaluation and validation of new networking solutions. Simulation, although fully controllable and easily reproducible, depends on simplified physical layer and channel models, which often produce optimistic results. Experimentation is also influenced by external random phenomena and limited testbed scale and availability, resulting in hardly repeatable and reproducible results. Previously, we have proposed the Trace-based Simulation (TS) approach to address the problem. TS uses traces of radio link quality and position of nodes to accurately reproduce past experiments in ns-3. Yet, in its current version, TS is not compatible with scenarios where Multiple-In-Multiple-Out (MIMO) is used. This is especially relevant since ns-3 assumes perfectly independent MIMO radio streams. In this paper, we introduce the Trace-based Wi-Fi Station Manager Model, which is capable of reproducing the Rate Adaptation of past Wi-Fi experiments, including the number of effective radio streams used. To validate the proposed model, the network throughput was measured in different experiments performed in the w-iLab.t testbed, considering Single-In-Single-Out (SISO) and MIMO operation using IEEE 802.11a/n/ac standards. The experimental results were then compared with the network throughput achieved using the improved TS and Pure Simulation (PS) approaches, validating the new proposed model and confirming its relevance to reproduce experiments previously executed in real environments. © 2021 ACM.

2021

Wide Scanning Angle Millimetre Wave 1 x 4 Planar Antenna Array on InP at 300 GHz

Authors
Hussain, B; Salgado, HM; Pessoa, LM;

Publication
APPLIED SCIENCES-BASEL

Abstract
Featured Application Short-range millimetre wave communications. The design of a uniformly spaced 1 x 4 linear antenna array using epitaxial layers of benzocyclobutene over an InP substrate is demonstrated. The array elements are conjugately matched with a uni-travelling carrier photodiode at the input. The phased array is optimised to counteract mutual coupling effects by introducing metal strips with isolated ground planes for each radiating element. The proposed antenna array can provide a gain of 10 dBi with a gain variation of +/- 3 dB. The array operates over a bandwidth of 10 GHz (295-305 GHz) with a wide scanning angle of 100 degrees in the broadside.

2021

Design and Fabrication of sub-THz Steerable Photonic Transmitter 1x4 Array for Short-Distance Wireless Links

Authors
Guerrero, LG; Graham, C; George, J; Renaud, C; George, G; Hussain, B; Salgado, HM; Pessoa, LM; Hinojosa, A; Fernandez, J; Porcel, MAG;

Publication
2021 JOINT EUROPEAN CONFERENCE ON NETWORKS AND COMMUNICATIONS & 6G SUMMIT (EUCNC/6G SUMMIT)

Abstract
In this paper we present the latest results on the design, fabrication and test of stand-alone photonic devices devoted to ultra-high bandwidth wireless access networks operating near the Terahertz (THz) band. We review the sub-THz photonics-based technology devices developed as part of the TERAPOD project, comprising the monolithically integrated Silicon Nitride photonic integrated circuit for phase distribution, the 1x4 array of integrated Uni-Travelling Carrier Photo-Diodes (UTC-PDs) and the radiative design of the high-frequency four element linear patch antenna array based on Benzocyclobutene (BCB) layers. We also report the suitability to assemble all those components in a robust small-form factor hybrid package.

2021

Resonant cavity assisted broadband CPW to rectangular waveguide transition on InP at 300 GHz

Authors
Hussain, B; Wang, J; Al-Khalidi, A; Wasige, E; Salgado, HM; Pessoa, LM;

Publication
2021 46TH INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER AND TERAHERTZ WAVES (IRMMW-THZ)

Abstract
An in-plane resonant cavity-assisted coplanar Housing waveguide (CPW) to rectangular waveguide (WG) transition is Cavity Bo). realized over an Indium Phosphide (InP) substrate with a thickness of 205 gm using a monopole radiating element. The simulated back-to-back (B2B) structure provides a bandwidth 16 GHz (288 - 304 GHz) with a return loss of 10 dB and insertion loss of 0.6 dB.

2021

Modelling of an Underwater Optical Wireless Communication System With Misalignment Tolerance

Authors
Marques, V; Salgado, HM; Pessoa, LM;

Publication
2021 IEEE 32ND ANNUAL INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR AND MOBILE RADIO COMMUNICATIONS (PIMRC)

Abstract
This papers proposes a multiple sensor-lens pair scheme to increase the misalignment tolerance and presents an accurate model of photon propagation based on the Monte Carlo simulation, that includes the photon refraction at the lenses interface and angular misalignment between emitter and receiver. The results show that the ideal divergence of the emitter's beam is around 15 degrees for a 1 metre Tx-Rx distance, increasing to 22 degrees for a shorter distance of 0.5 metres, but being independent of the water turbidity, showing that the geometry of the link is the dominant factor in such short-range links. Additionally, it was concluded that a 7 lenses scheme is approximately 3 times more offset tolerable than a single lens. Rotating the emitter increases the optimal divergence while rotating the plane of sensors decreases it.

2021

iBROW

Authors
Tavares, JS; Watson, S; Zhang, W; Figueiredo, JML; Cantu, HI; Wang, J; Al-Khalidi, A; Kelly, AE; Wasige, E; Salgado, HM; Pessoa, LM;

Publication
Springer Series in Optical Sciences - THz Communications

Abstract

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