1.
Pérez-Penichet, Carlos, et al.
(författare)
Poster abstract : Augmenting WSNs with interoperable 802.15.4 sensor tags
2017
Ingår i: SenSys 2017 - Proceedings of the 15th ACM Conference on Embedded Networked Sensor Systems. - New York, NY, USA : Association for Computing Machinery, Inc. - 9781450354592
Konferensbidrag (refereegranskat) abstract
The sensing capabilities of most sensor networks are fixed at the time of deployment. Adding new sensing capabilities to such networks is a costly and cumbersome process. We present Passive Sensor Tags, battery-free sensing devices that could be used to extend the sensing capabilities of an existing network. Sensor tags feature our new 802.15.4 receiver design which is suitable for micro-power operation, making battery-free tags possible. Because our tags can both transmit and receive 802.15.4 frames there is no need for any modification to the deployed hardware. We present preliminary measurements of transmission and reception range.
2.
Jang, Jeong Keun, et al.
(författare)
Area-efficient scheduling scheme based FFT processor for various OFDM systems
2018
Ingår i: 2018 IEEE ASIA PACIFIC CONFERENCE ON CIRCUITS AND SYSTEMS (APCCAS 2018). - : IEEE. - 9781538682401 ; , s. 338-341
Konferensbidrag (övrigt vetenskapligt/konstnärligt) abstract
This paper presents an area-efficient fast Fouriertransform (FFT) processor for orthogonal frequency-division multiplexing systems based on multi-path delay commutator architecture. This paper proposes a data scheduling scheme to reduce the number of complex constant multipliers. The proposed mixed-radix multi-path delay commutator FFT processor can support 128-, 256-, and 512-point FFT sizes. The proposed processor was synthesized using the Samsung 65-nm CMOS standard cell library. The proposed processor with eight parallel data paths can achieve a high throughput rate of up to 2.64 GSample/s at 330 MHz.
3.
Bengtsson, Lars, 1963
(författare)
Mikrodatorteknik
1995
Bok (övrigt vetenskapligt/konstnärligt) abstract
Första delen behandlar Microchips "Base-line"-kretsar och andra delen behandlar "Midrange"-kretsarna. De flesta funktioner belyses med konstruktionsexempel. Exempel och övningar är mycket hårdvarunära och boken behandlar konstruktion av mikrodatorer från grunden. Boken är avsedd för kurser i mikrodatorteknik på högskolan eller annan högre teknisk utbildning, men kan även användas som självstudiematerial eftersom de flesta exempel ges med detaljerade och verifierade lösningar av såväl hård- som mjukvaran. Tidigare erfarenhet av assemblerprogrammering är inte nödvändig men grundläggande kunskaper i digitalteknik förutsätts. Boken kan med fördel också läsas av rutinerade assemblerprogrammerare som vill veta hur prestanda hos de nya RISC-baserade PIC-controllerna står sig i konkurrensen med de mer etablerade enchipscontrollerna, t ex HC11 och 8751, som bygger på traditionell CISC-arkitektur.
4.
Kruglov, Dmitrii, 1994, et al.
(författare)
Enhancing mmWave On-Chip-Antennas Using In-Package Electromagnetic Bandgap Structures
2021
Ingår i: European Microwave Conference. - 1527-3342 .- 1557-9581. - 9782874870637 ; , s. 885-888
Konferensbidrag (refereegranskat) abstract
We propose a silicon on-Chip-in-Package antenna design featuring a simulated radiation efficiency of > 70% and an S11 matching better than −10 dB in the 112–125 GHz frequency range. High radiation performance is achieved by: (i) thinning the silicon substrate down to 100 μm through wafer-level grinding; (ii) embedding the IC in-between two PCBs, one of which forms an electromagnetic bandgap structure that attenuates the EM leakage inside the silicon substrate. Furthermore, since the die-embedding concept employs the gap-waveguide packaging technology, a universal contactless waveguide interconnect is realized between the IC and the radiating gap waveguide in the package. This will also enable modular antenna designs.
5.
Grudén, Mathias
(författare)
Wireless Sensor Network Systems in Harsh Environments and Antenna Measurement Techniques
2014
Doktorsavhandling (övrigt vetenskapligt/konstnärligt) abstract
Wireless sensor network (WSN) has become a hot topic lately. By using WSN things that previously were difficult or impossible to measure has now become available. One of the main reasons using WSN for monitoring is to save money by cost optimization and/or increase safety by letting the user knowing the physical status of the monitored structure. This thesis considers four main topics, empirical testing of WSN in harsh environments, antenna designs, antenna measurements and radio environment emulation.The WSN has been tested in train environment for monitoring of ball bearings and inside jet engines to monitor strain of blades and temperatures. In total, two investigations have been performed aboard the train wagon and one in the jet engine. The trials have been successful and provide knowledge of the difficulties with practical WSN applications. The key issues for WSN are robust communication, energy management (including scavenging) and physical robustness.For the applications of WSN in harsh environments antennas has to be designed. In the thesis, two antennas has been designed, one for train environment and one for the receiver in the jet engine. In the train environment, a more isotropic radiation pattern is preferable; hence a small dual layered patch antenna is designed. The antenna is at the limit of being electrically small; hence slightly lower radiation efficiency is measured. For the WSN in the jet engine, a directive patch array is designed on an ultra-thin and flexible substrate. The thin substrate of the antenna causes rather lower radiation efficiency. But the antenna fulfils the requirements of being conformal and directive.In reverberation chambers are used to measure antennas, but there are difficulties to provide a realistic radio environment, for example outdoor or on-body. In this thesis, a large reverberation chamber is designed and verified. It enables measurement between 400 MHz and 3 GHz. Also, a sample selection method is designed to provide a post processing possibilities to emulate the radio environment inside the chamber. The method is to select samples from a data set that corresponds to a desired probability density function. The method presented in this thesis is extremely fast but the implementation of the method is left for future research.
6.
Jobs, Magnus, 1984-
(författare)
Wireless Interface Technologies for Sensor Networks
2015
Doktorsavhandling (övrigt vetenskapligt/konstnärligt) abstract
The main focus of the work presented in this thesis concerns the development and improvement of Wireless Sensor Networks (WSNs) as well as Wireless Body Area Networks (WBANs). WSN consist of interlinked, wireless devices (nodes) capable of relaying data wirelessly between the nodes. The applications of WSNs are very broad and cover both wireless fitness monitoring systems such as pulse watches or wireless temperature monitoring of buildings, among others.The topics investigated in the work presented within this thesis covers antenna design, wireless propagation environment evaluation and modeling, adaptive antenna control and wireless nodes system design and evaluation. In order to provide an end-user suitable solution for wireless nodes the devices require both small form factor and good performance in order to be competitive on the marked and thus the main part of this thesis focuses on techniques developed and data collected to help achieve these goals. Several different prototype systems have been developed which have been used to measure data by the Swedish Defence Research Agency (FOI), GKN Aerospace Sweden AB, the Swedish Transport Administration. The system developed with GKN Aerospace was used to do real-time test measurements inside a running RM12 jet engine and required a substantial amount of measurements, environmental modeling and system validation in order to properly design a wireless system suitable for the harsh and fast fading environment inside a jet engine. For FOI improvements were made on a wearable wireless body area network initially developed during the authors master thesis work. Refinements included work on new generation wireless nodes, antenna packaging and node-supported diversity techniques.Work and papers regarding the design of different types of antennas suitable for wireless nodes are presented. The primary constraints on the presented antennas are the limited electrical size. The types of antennas developed include electrically small helix antennas manufactured both on stretchable substrates consisting of a PDMS substrate with Galinstan as the liquid metal conductors, screen printed silver ink for helix antennas and conformal dual patch antennas for wireless sensor nodes. Other standard type antennas are included on the wireless sensors as well.
7.
Liu, Yang, et al.
(författare)
A Study Towards Enhanced Reliability Performance of Remote Control and Monitoring Application Over Commercial Wireless Communication Networks
2006
Ingår i: 2006 International Conference on Wireless Communications, Networking and Mobile Computing. - : Institute of Electrical and Electronics Engineers (IEEE). - 1424405173 - 1424405173 ; , s. 1-4
Konferensbidrag (refereegranskat) abstract
Remote control and monitoring systems provide many useful operating advantages in industrial automation and demand highly reliable and secure communication means. Their widespread use is, however, limited because of the high cost of current communications in use making them economically infeasible. Hence, there is a need to develop new low cost communication and control concepts by making such solutions economically feasible. In this paper, we present a scheme for implementing reliable wireless communication links for application of remote control and monitoring system based on current available commercial wireless communication networks, e.g. GPRS/EDGE/UMTS. The reliability enhancement over wireless networks has been proposed and its performance has been studied. This paper examines the proposed solution by means of both analytical and numerical evaluation, and has shown that the demanded reliability performance can be met by using only commercial wireless communication networks.
8.
Åberg, Victor, 1992
(författare)
CMOS Data Converters for Closed-Loop mmWave Transmitters
2020
Licentiatavhandling (övrigt vetenskapligt/konstnärligt) abstract
With the increased amount of data consumed in mobile communication systems, new solutions for the infrastructure are needed. Massive multiple input multiple output (MIMO) is seen as a key enabler for providing this increased capacity. With the use of a large number of transmitters, the cost of each transmitter must be low. Closed-loop transmitters, featuring high-speed data converters is a promising option for achieving this reduced unit cost. In this thesis, both digital-to-analog (D/A) and analog-to-digital (A/D) converters suitable for wideband operation in millimeter wave (mmWave) massive MIMO transmitters are demonstrated. A 2×6 bit radio frequency digital-to-analog converter (RF-DAC)-based in-phase quadrature (IQ) modulator is demonstrated as a compact building block, that to a large extent realizes the transmit path in a closed-loop mmWave transmitter. The evaluation of an successive-approximation register (SAR) analog-to-digital converter (ADC) is also presented in this thesis. Methods for connecting simulated and measured performance has been studied in order to achieve a better understanding about the alternating comparator topology. These contributions show great potential for enabling closed-loop mmWave transmitters for massive MIMO transmitter realizations.
9.
Åberg, Victor, 1992, et al.
(författare)
RF PA Predistortion using Non-Linear RF-DACs
2022
Ingår i: 2022 IEEE Nordic Circuits and Systems Conference, NORCAS 2022 - Proceedings.
Konferensbidrag (refereegranskat) abstract
Analog and/or digital predistortion may be used to linearize power amplifiers (PAs) at the cost of additional hardware. We present a novel scheme which uses segmented non-linear RF-DACs to linearize PAs at no additional hardware cost. An expanding segmented scaling chosen at design time may be adjusted using DAC bias, allowing linearization to be adapted. Simulations demonstrate the robustness and flexibility of the approach, achieving excellent overall linearity over a large range of DAC and PA bias conditions.
10.
Åberg, Victor, 1992
(författare)
Wideband CMOS Data Converters for Linear and Efficient mmWave Transmitters
2022
Doktorsavhandling (övrigt vetenskapligt/konstnärligt) abstract
With continuously increasing demands for wireless connectivity, higher carrier frequencies and wider bandwidths are explored. To overcome a limited transmit power at these higher carrier frequencies, multiple input multiple output (MIMO) systems, with a large number of transmitters and antennas, are used to direct the transmitted power towards the user. With a large transmitter count, each individual transmitter needs to be small and allow for tight integration with digital circuits. In addition, modern communication standards require linear transmitters, making linearity an important factor in the transmitter design. In this thesis, radio frequency digital-to-analog converter (RF-DAC)-based transmitters are explored. They shift the transition from digital to analog closer to the antennas, performing both digital-to-analog conversion and up-conversion in a single block. To reduce the need for computationally costly digital predistortion (DPD), a linear and wellbehaved RF-DAC transfer characteristic is desirable. The combination of non-overlapping local oscillator (LO) signals and an expanding segmented non-linear RF-DAC scaling is evaluated as a way to linearize the transmitter. This linearization concept has been studied both for the linearization of the RF-DAC itself and for the joint linearization of the cascaded RF-DAC-based modulator and power amplifier (PA) combination. To adapt the linearization, observation receivers are needed. In these, high-speed analog-to-digital converters (ADCs) have a central role. A high-speed ADC has been designed and evaluated to understand how concepts used to increase the sample rate affect the dynamic performance.
