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A Model to Improve the Accuracy of WSN Simulations
Gama, Oscar; Carvalho, Paulo; Mendes, P. M.Simulation studies have been extensively adopted in the networking research community. Nevertheless, the performance of the software components running within the network devices is often not modeled by generic network simulators. This aspect is particularly important in wireless sensor networks (WSN). As motes present very limited computing resources, the overhead of the software components cannot be ignored. ...
Modelling the impact of software components on wireless sensor network performance
Gama, Oscar; Carvalho, Paulo; Mendes, P. M.Network Simulators are often used to study multiple aspects of data communications in distinct scenarios, including wireless sensor networks (WSN). However, the performance of the software components running in the network nodes is normally neglected by the simulators. This aspect is particularly important in WSNs, as nodes have very limited computing resources. In order to study the impact of software componen...
Super-regenerative receiver at 433MHz
Carmo, J. P.; Ribeiro, J. C.; Mendes, P. M.; Correia, J. H.This paper presents a receiver for operation in the 433 MHz ISM band. The selected architecture explores the super regeneration phenomena to achieve a high sensitivity for applying in wireless implantable microsystems. This radio frequency (RF) chip can be supplied with a voltage of only 3 V for demodulating signals with powers in the range [ 100, 40] dB. The codulation (modulation and coding) scheme of the bi...
A low-power/low-voltage CMOS wireless interface at 5.7 GHz with dry electrodes ...
Dias, N. S.; Carmo, J. P.; Mendes, P. M.; Correia, J. H.This paper describes a low-power/low-voltage CMOS wireless interface (CMOS-WiI) at 5.7 GHz with dry electrodes for congnitive networks. The electrodes are 4 x 4 microtip arrays and acquire electroencephalogram (EEG) signals in key- points for processing. The CMOS-WiI was fabricated in a UMC 0.18 µm RF CMOS process and its total power consumption is 23mW with a voltage-supply of only 1.5 V. The carrier frequency...
433 MHz implantable wireless stimulation of spinal nerves
Carmo, J. P.; Silva, M. F.; Ribeiro, J. C.; Mendes, P. M.; Correia, J. H.This paper presents a implantable wireless microsystem concept for operation in the 433 MHz ISM band. The proposed microsystem is composed by two independent subsystems: the electrostimulation and the radio frequency (RF) subsystems. The electrostimulation part is a silicon box with groves to pass the nerves to be stimulated. The cover of the silicon box contains electrodes for electrical contacting with the ne...
A time-slot scheduling algorithm for e-health wireless sensor networks
Gama, Oscar; Carvalho, Paulo; Mendes, P. M.http://www.ieee-healthcom.org/2010/about.html ; For e-health wireless sensor networks presenting significant traffic loads, MAC protocols based on deterministic scheduling algorithms are consensually considered more adequate than protocols based on random access algorithms. Indeed, TDMA-based MAC protocols are able to control the delay bound and save power by eliminating collisions. However, these protocols al...
A platform with combined environmental and physiological wireless data acquisit...
Gama, Oscar; Martins, H.; Pereira, C.; Soares, S.; Valente, A.; Ribeiro, V. S.; Carvalho, Paulo; Mendes, P. M.http://isami2010.di.uminho.pt/ ; Ambient Assisted Living is based on a set of technologies with the aim to provide an enhanced support to people’s daily life. One important field deals with the offer of new solutions for healthcare. Those solutions intend to improve the population quality of life and reduce costs associated with healthcare. Before that happens, new platforms, hardware and software, must be ava...
A 2.4-GHz CMOS short-range wireless-sensor-network interface for automotive app...
Carmo, J. P.; Mendes, P. M.; Couto, Carlos; Correia, J. H.This paper describes a CMOS interface for shortrange wireless sensor networks (CMOS-SRWSN interface). The sensor interface is composed of a sensor readout, electronics for processing and control, a memory, a radio-frequency CMOS transceiver for operation in the 2.4-GHz industrial, scientific, and medical bands, and a planar antenna. The receiver has a sensitivity of −60 dBm and consumes 6.3 mW from a 1.8-V supp...
New dry electrodes based on iridium oxide (IrO) for non-invasive biopotential r...
Dias, N. S.; Carmo, J. P.; Silva, A. F.; Mendes, P. M.; Correia, J. H.This paper presents a new type of dry electrodes for acquisition of biopotentials and stimulation. These dry electrodes are composed by 16 microtip structures (by forming an array of 4×4 microtips), which were fabricated through bulk micromachining of a 100 -type silicon substrate in a potassium hydroxide (KOH) solution. The fabrication process was trimmed in a way that each microtip presents solid angles of 5...
An improved MAC Protocol with reconfiguration scheme for Wireless e-Health Syst...
Gama, Oscar; Afonso, José A.; Carvalho, Paulo; Mendes, P. M.To provide a reliable assistance to patients, emergency and intensive care systems have increased demands for quality of service at different levels, including at the MAC layer. The Low Power Real Time (LPRT) MAC protocol presents suitable characteristics to address these demands due to its efficient bandwidth allocation, low energy consumption, and bounded latency. Yet, this MAC protocol may still present a si...
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