Dissertations / Theses on the topic 'Radio link design'
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Hamied, Khalid Abdul-Ariz. "Advanced radio link design and radio receiver design for mobile communications." Diss., Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/15940.
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Alam, Tasmeer. "LINK DEPENDENT ADAPTIVE RADIO – DESIGN FOR iNET." International Foundation for Telemetering, 2017. http://hdl.handle.net/10150/626995.
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This paper focuses on the design of a simple Time Division Multiple Access (TDMA) signaling structure for the Link Dependent Adaptive Radio (LDAR) prototype wireless radio communication system to meet the timing requirements of the iNET standard. Built for aeronautical telemetry, LDAR adapts its modulation and coding scheme based on the channel condition in real time. In this paper, a simple protocol for transmission of Command Message and Data Message between Ground Station and Test Article is discussed. This protocol includes all analysis for the continuous adaptation of modulation scheme and coding rate to maximize throughput while ensuring a minimum level of link quality. This project was a collaborative effort between Morgan State University and Georgia Tech Research Institute and is a continuation of our previously published work on LDAR.
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Volos, Haris I. "Cognitive Radio Engine Design for Link Adaptation." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/29148.
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In this work, we make contributions in three main areas of Cognitive Engine (CE) design for link adaptation. The three areas are CE design, CE training, and the impact of imperfect observations in the operation of the CE.
First, we present a CE design for link adaptation and apply it to a system which can adapt its use of multiple antennas in addition to modulation and coding. Our design moves forward the state of the art in several ways while having a simple structure. Specifically, the CE only needs to observe the number of successes and failures associated with each set of channel conditions and communication method. From these two numbers, the CE can derive all of its functionality: estimate confidence intervals, balance exploration vs. exploitation, and utilize prior knowledge such as communication fundamentals. Finally, the CE learns the radio abilities independently of the operation objectives. Thus, if an objective changes, information regarding the radio's abilities is not lost.
Second, we provide an overview of CE training, and we analytically estimate the number of trials needed to conclusively find the best performing method in a list of methods sorted by their potential performance. Furthermore, we propose the Robust Training Algorithm (RoTA) for applications where stable performance is of topmost importance. Finally, we test four key training techniques and identify and explain the three main factors that affect performance during training.
Third, we assess the impact of the estimation noise on the performance of a CE. Furthermore, we derive the effect of estimation delay, in terms of the correlation between the observed SNR and the true SNR. We evaluate the effect of estimation noise and delay to the operation of the CE individually and jointly. It is found that impairments on learning make the CE more conservative in its choices leading to submaximal performance. It is found that the CE should learn using the impaired observations, if the observations are highly correlated with the actual conditions. Otherwise, it is better for the CE to learn with knowledge of the ideal conditions, if that knowledge is available.Ph. D.
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Britto, Elizabeth, and Patricia Mwangi. "CHANNEL ISSUES FOR DESIGN OF THE iNET RADIO LINK PROTOCOL." International Foundation for Telemetering, 2005. http://hdl.handle.net/10150/604896.
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ITC/USA 2005 Conference Proceedings / The Forty-First Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2005 / Riviera Hotel & Convention Center, Las Vegas, NevadaThis paper presents the issues related to the modeling and performance of the Radio Channel used in Telemetry. Because of the physical environment one expects stressed channel conditions due to multipath, shadowing, and high doppler shift caused by high speeds of up to mach 3. Prior work has created useful data and models for analysis of these radio channels. This paper will develop features of a channel simulator that will allow for evaluation of radio protocols for iNET. Substantial work has also been done to develop requirements for the iNET networked radio environment. This paper will map these requirements into technical features required for the radio link and consider how these will relate to the effects of the channels.
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Wu, Yang. "Optical heterodyned radio-over-fiber link design using electroabsorption & electrooptic modulators /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2004. http://wwwlib.umi.com/cr/ucsd/fullcit?p3123659.
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Hossain, Abu Zafar Mohammad Ekram. "Radio link control and transport layer protocol design issues in wireless IP networks." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0017/NQ58572.pdf.
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Aden, Hassan Abdullahi, and Källqvist Rasmus Karlsson. "Evaluating LoRa Physical as a Radio Link Technology for use in a Remote-Controlled Electric Switch System for a Network Bridge Radio-Node." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-247895.
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This report explores the design of a system for remotely switching electronics on and off within a range of at least 15 km, to be used with battery driven radio nodes for outdoor Wi-Fi network bridging. The application of the network bridges are connecting to remote networks, should Internet infrastructure fail during an emergency.The problem statement for the report was “What is a suitable radio link technology for use in a remote controlled electrical switch system and how should it best be put to use?” To answer the question, delimitation was done to exploring Low Power Wide Area Network (LPWAN) link technologies, due to their prior use within power constrained devices.Long Range-radio, abbreviated LoRa, is a LPWAN radio modulation technique and was determined to be a good candidate as a suitable link technology for the remote electrical switch system. The range of LoRa is achieved by drastically lowering the data rate of the transmission, and is suitable for battery-powered or energy harvesting devices such as those found in the field of Internet of Things.A LoRa-based transmitter and receiver pair was implemented, and measured to have a packet delivery ratio of over 95% at a distance of 2 km, measured between two bridges. Data at further distances could not be accurately determined, because of the LoRa transceiver giving faulty readings.No conclusion could be made about the suitability for using a LoRa based system to solve the problem, partially due to an improper method for testing the radio performance was used, and partially due to an inconclusive measurement result.Denna rapport utforskar designen av ett system för att fjärrstyrt slå på eller av elektronik över ett avstånd på minst 15 km, för att användas med batteridrivna radionoder för nätverksbryggning utomhus med Wi-Fi. Tillämpningsområdet för nätverksbryggorna är att koppla samman avlägsna nätverk, om Internetinfrastruktur skulle sluta fungera vid en nödsituation.Problemställningen för rapporten var ”Vad är en lämplig radiolänksteknik att använda i ett fjärrstyrt elektriskt strömbrytarsystem, och hur ska det bäst brukas?”. För att svara på frågan gjordes en avgränsning att utforska Low Power Wide Area Network (LPWAN)-länktekniker, på grund av deras tidigare användning inom effektbegränsade enheter.Long Range-radio, förkortat LoRa, är en radiomodulationsteknik som används för att skicka data över långa avstånd med energibegränsade enheter. LoRa:s räckvidd uppnås genom att drastiskt sänka datatakten, och lämpar sig för bruk i batteridrivna eller energiskördande enheter, likt de som återfinns inom fältet Internet of Things.Ett LoRa-baserat sändaroch mottagarpar implementerades, och uppmättes till att ha en paketlevereringsmängd på över 95% vid ett avstånd på 2 km, mätt mellan två broar. Data vid större avstånd kunde inte bli bestämt noggrant, eftersom LoRa transceivern gav felaktiga avläsningar. Ingen slutsats kunde göras för lämpligheten för att använda ett LoRa-baserat system för att lösa problemet, delvist för att en olämplig metod för att testa radions prestanda använts, och delvist på grund av ett ofullständigt mätresultat.
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Frykskog, David, and Hjalmar Jonsson. "Construction of RF-link budget template for transceiver modelling." Thesis, Linköpings universitet, Fysik och elektroteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-162159.
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This master thesis report details the process of developing a simulation platform for radio transceivers with a focus on analog receiver front end system design. The platform was implemented in the National Instruments VSS environment for the company Ericsson AB.
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Benzerbadj, Ali. "Approche inter-couches pour l'économie d'énergie et la fiabilité dans les Réseaux de Capteurs Sans Fil dédiés aux Applications Critiques de Surveillance." Thesis, Brest, 2018. http://www.theses.fr/2018BRES0034/document.
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Les Réseaux de Capteurs Sans Fil (RCSFs) constituent une classe particulière des réseaux Ad hoc, faisant l'objet de recherches intensives. Ils sont considérés comme un outil très puissant pour connecter le monde physique et le monde numérique. Ils se composent d'un grand nombre de noeuds capteurs dotés de ressources limitées en termes d'énergie, de portée de capture et de communication, de vitesse de traitement et de capacité de stockage. Ils sont déployés dans un environnement intérieur ou extérieur, et ce dans de nombreux domaines d'application tels que l'armée, l'environnement, la santé, la maison et l'agriculture. La rareté des ressources des noeuds capteurs et la non fiabilité des liaisons sans fil motivent la plupart des problématiques dans le domaine des RCSFs, à savoir l'énergie, la couverture, la connectivité, le routage, la tolérance aux pannes et la sécurité. L'objectif de cette thèse est de proposer un protocole de surveillance inter-couches, à efficacité énergétique et fiable, pour la surveillance des zones sensibles clôturées, tel qu'un site pétrolier ou nucléaire, utilisant les réseaux de capteurs sans fil avec un cycle d'activité, et avec prise en compte des liens asymétriques dus au phénomène de l'irrégularité de la radio. Initialement, le protocole proposé identifie les noeuds de bordure du RCSF pour les utiliser comme nœuds sentinelles, c.-à-d., des noeuds qui sont toujours dans un état actif. Les noeuds restants sont utilisés en tant que noeuds relais avec un cycle d'activité, pendant la phase de routage des alertes vers le noeud puits. Le processus d'identification des noeuds de bordure ainsi que le routage des alertes, sont assurés par le protocole Greedy Perimeter Stateless Routing through Symmetrical Links (GPSR-SL) qui est une version améliorée du protocole GPSR, reposant sur un graphe de connectivité représenté sous forme de disques non-unité (N-UDG). Le protocole de surveillance inter-couches proposé a été implémenté et ses performances ont été évaluées en utilisant l'environnement de simulation OMNeT++/Castalia. Les résultats de performance montrent que ce protocole permet d'obtenir un ratio de livraison de paquets plus élevé d'environ 3.63%, une efficacité énergétique et une latence satisfaisante par rapport au même protocole basé sur le GPSR originalWireless Sensor Networks (WSNs) are a special class of Ad hoc networks, which are under intensive research.They are considered as a very powerful tool to connect the physical and the digital worlds. They consist of a largenumber of sensor nodes that are characterized with limited resources in terms of energy, range of sensing and communication, processing speed and storage capacity.They are deployed in an indoor or outdoor environment in many application domains such as army, environment, health, home and agriculture. The scarcity of sensor node resources and the unreliability of wireless links drive most of the research issues in the field of WSNs, namely energy, coverage, connectivity, routing, fault tolerance and security. The aim of this thesis is to propose an energyefficient and reliable cross-layer surveillance protocol for sensitive fenced areas, such as oil or nuclear sites, using duty-cycled WSNs with asymmetrical links due to the radio irregularity phenomenon. Initially, the proposed protocol identifies the boundary nodes of the deployedWSN, to be used as sentinel nodes, i.e., nodes that are always in an active state. The remaining nodes are usedas duty-cycled relay nodes during the routing phase to relay alerts towards the sink. The boundary nodes identification process and alert routing are both performed using an enhanced version of the Greedy Perimeter Stateless Routing (GPSR) protocol, referred to as GPSR over Symmetrical Links (GPSR-SL) and which relies on a Non Unit Disk Graph (N-UDG). The proposed cross-layer surveillance protocol has been implemented and its performance has been evaluated under the OMNeT++/Castalia simulation environment. Performance results show that this protocol achieves higher Packet Delivery Ratio by up to 3.63%, energy .efficiency and satisfactory latency when compared to the same protocol based on the original GPSR
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Josefsson, Elias. "Multi-viewed Visualization of Modularity for Product Line Management : Case study at Hardware Radio Design, Ericsson AB." Thesis, KTH, Maskinkonstruktion (Inst.), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-157048.
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The purpose of this thesis is to investigate how visualization may help Hardware Radio Design at Ericsson AB in their modularity work. As the market requires more and more versions of Radio Units, Ericsson has introduced a modular approach to product family development. With a good modularity, more variants can be developed with the same amount of resources and increase the profit margin. In the work of selecting modular plan, different stakeholders need to understand and evaluate the effect on multiple aspects. Firstly, stakeholders at Ericsson were interviewed to identify what information related to modularity that would benefit from being visualized where development time, resource usage and time-plan have been focused. Secondly, concept designs of visualizations were iteratively developed for the focused areas. The concepts are built on well-known charts, e.g. organizational charts for product structure, bar charts for resource usage and GANTT chart for time plan. Lastly, a web-application was developed with multiple interactive views and models to be able to validate the results with stakeholders. The conclusion of the thesis is that visualization of product family modularity very likely would help stakeholders to understand how modular plans affect different aspects. By supporting multiple views based on the same data, stakeholders with different viewpoints can together discuss and make better decisions. The results also show that it is very likely that a visualization tool for modularity would facilitate the communication amongst the whole organization. As future work, a more extensive verification of the visualizations and tool are necessary to ensure its value in a real development process. Great opportunities exist for expanding the tool with more types of elements, such as software and test cases. Integration with other systems may also provide additional values, such as integration with time reporting system to evaluate time estimates with real outcome.Syftet med denna uppsats är att undersöka hur visualisering kan hjälpa Hardware Radio Design på Ericsson AB i sitt modularitetsarbete. För att kunna tillmötesgå marknades krav på fler och fler versioner av radioenheter, har Ericsson infört en modulbaserad utveckling av sin produktfamilj. Med en modulär produktfamilj kan fler varianter utvecklas med samma mängd resurser och därmed stärka Ericssons position på marknaden. I arbetet med att fastslå moduläriteten måste olika intressenter förstå och utvärdera effekten utifrån flera aspekter. Inledningsvis intervjuades utvalda intressenter på Ericsson för att identifiera den information, relaterad till modularitet, som gagnas av visualisering där utvecklingstid, resursanvändning och tidsplanering har fokuserats. Därefter utvecklades visualiseringskoncept för valda fokusområden som utvärderades av intressenterna. Koncepten innehåller kända diagram, t.ex. organisationschema för produktstruktur, stapeldiagram för resursanvändning och GANTTschema för tidsplanering. Slutligen byggdes en web-applikation med flera interaktiva vyer och modeller för att kunna validera resultaten. Slutsatsen i projektet är att en visualisering av produktfamiljens modularitet mycket sannolikt skulle hjälpa intressenter att förstå hur ett modulärt förslag påverka olika aspekter. Genom att, utifrån samma data, generera flera vyer kan aktörer med olika intressen tillsammans diskutera och fatta bättre beslut. Resultaten visar att ett visualiseringsverktyg för modularitet med stor sannolikhet också skulle underlätta kommunikationen mellan olika delar av organisationen. Som framtida arbete bör en omfattande verifiering av visualiseringarna och verktyget göras för att säkerställa dess värde i en verklig utvecklingsprocess. Det finns även stora möjligheter att utveckla verktyget med fler typer av element, t.ex. mjukvara och testfall. Även integration med andra system kan ge ytterligare värden, t.ex. tidrapporteringssystem för att utvärdera gjorda tidsestimat med verkliga utfall.
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Lazaris, Dimitrios Theodoros. "Design and evaluation of portable antennas for location of sources of radio noise emanating from power-line hardware." Thesis, Monterey, California. Naval Postgraduate School, 1992. http://hdl.handle.net/10945/23619.
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Approved for public release; distribution is unlimitedPower-line noise (PLN) is a major contributor to factors which cause the loss of signals at naval receiving sites. Navy Signal-to-Noise Enhancement Program (SNEP) teams have developed portable instrumentation for the location of RF noise-producing power-line hardware. An important component of the instrumentation is a lightweight antenna with modest directivity and wide bandwidth (60-800 MHz). The purpose of this study is the design, construction, analysis, and measurement of three customized Log-periodic Dipole Arrays (LPDA) for use in locating PLN sources. Modifications to standard LPDA designs include a feeder boom with convenient construction features and emphasis on a compact, lightweight, portable structure. The Numerical Electromagnetics Code (NEC) was used to analyze the performance of the various designs. Input impedances were measured in operational environments using network analyzers. The final designed were field-tested at a U.S. Naval site in Okinawa and found to be completely acceptable for SNEP use.
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Gong, Fei. "Front End Circuit Module Designs for A Digitally Controlled Channelized SDR Receiver Architecture." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1322606039.
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Akour, Amneh M. "Design Techniques for Manufacturable 60GHz CMOS LNAs." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1306443049.
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Shakoori, Moghadam Monfared Shaghayegh. "Design and prototyping of indoor positioning systems for Internet-of-Things sensor networks." Doctoral thesis, Universite Libre de Bruxelles, 2021. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/316363.
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Accurate indoor positioning of narrowband Internet-of-Things (IoT) sensors has drawn more attention in recent years. The introduction of Bluetooth Low Energy (BLE) technology is one of the latest developments of IoT and especially applicable for Ultra-Low Power (ULP) applications. BLE is an attractive technology for indoor positioning systems because of its low-cost deployment and reasonable accuracy. Efficient indoor positioning can be achieved by deducing the sensor position from the estimated signal Angle-of-Arrival (AoA) at multiple anchors. An anchor is a base station of known position and equipped with a narrowband multi-antenna array. However, the design and implementation of indoor positioning systems based on AoA measurements involve multiple challenges. The first part of this thesis mainly addresses the impact of hardware impairments on the accuracy of AoA measurements. In practice, the subspace-based algorithms such as Multiple Signal Classification (MUSIC) suffer from sensitivity to array calibration errors coming from hardware imperfections. A detailed experimental implementation is performed using a Software Defined Radio (SDR) platform to precisely evaluate the accuracy of AoA measurements. For this purpose, a new Over-the-Air (OTA) calibration method is proposed and the array calibration error is investigated. The experimental results are compared with the theoretical analysis. These results show that array calibration errors can cause some degrees of uncertainty in AoA estimation. Moreover, we propose iterative positioning algorithms based on AoA measurements for low capacity IoT sensors with high accuracy and fair computational complexity. Efficient positioning accuracy is obtained by iterating between the angle and position estimation steps. We first develop a Data-Aided Maximum a Posteriori (DA- MAP) estimator based on the preamble of the transmitted signal. DA-MAP estimator relies on the knowledge of the transmitted signal which makes it impractical for narrowband communications where the preamble is short. For this reason, a Non-Data- Aided Maximum a Posteriori (NDA-MAP) estimator is developed to improve the AoA accuracy. The iterative positioning algorithms are therefore classified as Data-Aided Iterative (DA-It) and Non-Data-Aided Iterative (NDA-It) depending on the knowledge of the transmitted signal that is used for estimation. Both numerical and experimental analyses are carried out to evaluate the performance of the proposed algorithms. The results show that DA-MAP and NDA-MAP estimators are more accurate than MUSIC. The results also show that DA-It comes very close to the performance of the optimal approach that directly estimates the position based on the observation of the received signal, known as Direct Position Estimation (DPE). Furthermore, the NDA-It algorithm significantly outperforms the DA-It because it can use a much higher number of samples; however, it needs more iterations to converge. In addition, we evaluate the computational savings achieved by the iterative schemes compared to DPE through a detailed complexity analysis. Finally, we investigate the performance degradation of the proposed iterative algorithms due to the impact of multipath and NLOS propagation in indoor environments. Therefore, we develop an enhanced iterative positioning algorithm with an anchor selection method in order to identify and exclude NLOS anchors. The numerical results show that applying the anchor selection strategy significantly improves the positioning accuracy in indoor environments.Doctorat en Sciences de l'ingénieur et technologie
info:eu-repo/semantics/nonPublished
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Huang, Wei-Chi, and 黃偉奇. "D8PSK Software Radio Design for Air-Ground Data Link." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/69248317168809304789.
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碩士國立海洋大學
電機工程學系
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For data communications in CNS/ATM, the air-ground aeronautical telecommunication network requires irregular, high data rates of transmission in long bursts. The Aircraft Communication Addressing and Reporting System ( ACARS ) is a VHF radio currently used in air-ground Communications. Due to its low data transmission rate of 2.4 Kb/s, small communication capacity and high cost, ACARS can''t cope with the fast growing needs of high throughput in aeronautical communications. Because VHF Digital Link ( VDL ) can operate at a bit rate up to 31.5 Kb/s, and has larger capacity, it will gradually replace ACARS and become the key VHF data link system for the next generation air-ground data communications. The objective of the thesis is to develop the mode3 VDL prototype system which implements D8PSK baseband/IF band transceiver for physical layer protocols, and evaluate its performance over a Gaussian white noise channel when estimation errors of synchronization parameters including carrier frequency, phase and symbol timing exist. By the use of DSP on-line simulator ( LabVIEW ) and the associated wideband ADC/DAC module board, the VDL transceiver system is simulated, designed and tested ant its performance is assessed. The results from the thesis can facilitate the DSP chip-based design in the future for practical applications, and is anticipated to establish the key technology for the next generation air-ground communications.
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Al-Tamimi, Majid. "MAC Protocol Design for Parallel Link Rendezvous in Ad Hoc Cognitive Radio Networks." Thesis, 2010. http://hdl.handle.net/10012/5006.
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The most significant challenge for next wireless generation is to work opportunistically on the spectrum without a fixed spectrum allocation. Cognitive Radio (CR) is the candidate technology to utilize spectrum white space, which requires the CR to change its operating channel as the white space moves. In a CR ad-hoc network, each node could tune to a different channel; as a result, it cannot communicate with other nodes. This different tuning is due to the difficulty of maintaining Common Control Channel (CCC) in opportunistic spectrum network, and keeping the nodes synchronized in ad-hoc network. The CR ad-hoc network requires a protocol to match tuning channels between ad-hoc nodes, namely, rendezvous channels.
In this thesis, two distributed Medium Access Control (MAC) protocols are designed that provide proper rendezvous channel without CCC or synchronization. The Balanced Incomplete Block Design (BIBD) is used in both protocols to provide our protocols a method of rendezvous between CR ad-hoc nodes. In fact, the BIBD guarantees there is at least one common element between any two blocks. If the channels are assigned to the BIBD elements and the searching sequence to the BIBD block, there is a guarantee of a rendezvous at least in one channel for each searching sequence. The first protocol uses a single-BIBD sequence and a multi-channel sensing. Alternatively, the second protocol uses a multi-BIBD sequence and a single-channel sensing.
The single-sequence protocol analysis is based on the discrete Markov Chain. At the same time, the sequence structure of the BIBD in a multi-sequence protocol is used to define the Maximum Time to Rendezvous (MTTR). The simulation results confirm that the protocols outperform other existing protocols with respect to Time to Rendezvous (TTR), channel utilization, and network throughput. In addition, both protocols fairly distribute the network load on channels, and share the channels fairly among network nodes. This thesis provides straight forward and efficiently distributed MAC protocols for the CR ad-hoc networks.
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Hossain, Ekram. "Radio link control and transport layer protocol design issues in wireless IP networks." Thesis, 2000. https://dspace.library.uvic.ca//handle/1828/9562.
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Packet-switched wireless data networks built upon IP (Internet Protocol)-based infrastructure are being envisioned to provide ubiquitous Internet access to mobile users. Supporting packet-data services along with the cellular voice services in an integrated networking framework gives rise to new network infrastructure and protocol design issues that are to be resolved to facilitate the introduction of the next generation wireless IP networks.
This thesis addresses several protocol design issues in the area of wireless packet data networking, namely, retransmission control design for multichannel protocols, radio link level protocol for dynamic rate and error control, inter-layer protocol dependency, radio link-layer and transport-layer protocol fairness and radio link-level dynamic bandwidth allocation. A retransmission control policy for a multichannel S-ALOHA (slotted ALOHA) protocol in a high speed wireless data network is proposed and analyzed. A sub-optimal dynamic rate adaptation procedure is proposed for uplink data transmission in WCDMA (Wideband Code Division Multiple Access)-based wireless IP networks. The performance of this scheme is analyzed using a novel ‘mean-sense’ approach for interference calculation in cellular WCDMA environment. The impact of macrodiversity packet combining on transport-protocol throughput performance is analyzed under different link-level retransmission control policies. A unified TDMA (Time Division Multiple Access)-based centralized bandwidth management mechanism is proposed as a link-level solution for providing service fairness among competing users for uplink data transmission in a wireless IP network. TCP (Transmission Control Protocol) performance is evaluated under different transport-level packet scheduling policies in a correlated fading environment and a time frame-based scheduling policy is proposed to provide service fairness among mobile users in the case of downlink transmission. A set of centralized burst-level bandwidth allocation policies are investigated as a means of service integration with QoS (Quality of Service) provisioning in the wireless IP air interface.Graduate
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Salamon, Stephen John. "Modelling Terrestrial Clear-Air Microwave Radio Fading." Thesis, 2022. https://hdl.handle.net/2440/136413.
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The technology of communication systems between population centres has undergone much change over the last century an a half, but radio links continue to be an important part of communication networks. A challenging part of their design is allowing for variations in received signal level, known as radio fading and enhancement, due to the atmosphere between transmitter and receiver. At high frequencies rain fading is the limiting factor, but below about 10 GHz, temperature and humidity gradients, in the absence of precipitation, may produce clear-air fading that becomes the limiting factor. As the refractive index of the air at radio frequencies depends on temperature and humidity, vertical gradients of these parameters cause bending of ray-paths. Multiple signals may arrive at the receiver over different paths, resulting in multipath fading. Sometimes almost no signal at all is able to find its way from transmitter to receiver, resulting in an impairment known as median depression; this may last for an hour or more, with median signal level up to 50 dB below normal. Recent long-term observations show this fading to be particularly severe in some parts of Australia, but not well predicted by pre-existing models. This thesis develops a new international model for clear-air fading. Weather forecasting has made significant progress in recent years due to numerical weather prediction (NWP) models, so radio propagation researchers have aimed to use these models to predict the state of the atmosphere, and Fourier split-step parabolic equation modelling (PEM) to predict radio propagation. Considering this, we begin this thesis by investigating Fourier split-step PEM, developing new techniques for dealing with finite conductivity lower boundaries, estimating the absorbing upper boundary height, and for dealing with irregular terrain, in both two and three dimensions. A brief description of the internationally adopted empirical model for diffraction over terrain (Rec. ITU-R P526-15, 2019), completes this chapter. We then examine radio refractivity gradient cumulative distributions derived from NWP data, comparing them with measurements from radiosondes, and data from sensors mounted on towers. We find the NWP prediction of anomalous gradients in the surface atmospheric layer to be poor, and develop a new parameter, surface refractivity anomaly, derived from surface weather station time-series data. We find this parameter useful in predicting vertical radio refractivity gradients in the atmospheric surface layer. Due to NWP surface gradient accuracy problems, we adopt the empirical regression model approach to fading severity prediction. This is not new, but we now have the benefit of more fading data from more regions of the world, and we have our new prediction parameters, generated from several years of data from thousands of worldwide weather stations. We make novel refinements to the modelling of clear-air fading, by first replacing ordinary least squares (OLS) regression with generalised least squares (GLS) regression, to take spatial correlation into account. We then employ the geostatistical technique of universal kriging, to further improve prediction accuracy. Our new fading model, as described in this thesis, is now the internationally approved terrestrial line-of-sight model for fading due to multipath and related mechanisms (Rec. ITU-R P.530-18, 2021).Thesis (Ph.D.) -- University of Adelaide, School of Electrical and Electronic Engineering, 2022
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Ma, Hao. "Performance Analysis of Secondary Link with Cross-Layer Design and Cooperative Relay in Cognitive Radio Networks." Thesis, 2012. http://hdl.handle.net/10754/234954.
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In this thesis, we investigate two different system infrastructures in underlay cognitive
radio network, in which two popular techniques, cross-layer design and cooperative
communication, are considered, respectively. In particular, we introduce the Aggressive
Adaptive Modulation and Coding (A-AMC) into the cross-layer design and
achieve the optimal boundary points in closed form to choose the AMC and A-AMC
transmission modes by taking into account the Channel State Information (CSI) from
the secondary transmitter to both the primary receiver and the secondary receiver.
What’s more, for the cooperative communication design, we consider three different
relay selection schemes: Partial Relay Selection, Opportunistic Relay Selection and
Threshold Relay Selection. The Probability Density Functions (PDFs) of the Signal-to-
Noise Ratio (SNR) in each hop for different selection schemes are provided, and
then the exact closed-form expressions for the end-to-end packet loss rate in the secondary
link considering the cooperation of the Decode-and-Forward (DF) relay for
different relay selection schemes are derived.
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Hu, Kangmin. "Analysis and design on low-power multi-Gb/s serial links." Thesis, 2011. http://hdl.handle.net/1957/21944.
Full textAbstract:
High speed serial links are critical components for addressing the growing demand for I/O bandwidth in next-generation computing applications, such as many-core systems, backplane and optical data communications. Due to continued process scaling and circuit innovations, today's CMOS serial link transceivers can achieve tens of Gb/s per pin. However, most of their reported power efficiency improves much slower than the rise of data rate. Therefore, aggregate I/O power is increasing and will exceed the power budget if the trend for more off-chip bandwidth is sustained.
In this work, a system level statistical analysis of serial links is first described, and compares the link performance of Non-Return-to-Zero (2-PAM) with higher-order modulation (duobinary) signaling schemes. This method enables fast and accurate BER distribution simulation of serial link transceivers that include channel and circuit imperfections, such as finite pulse rise/fall time, duty cycle variation, and both receiver and transmitter forwarded-clock jitter.
Second, in order to address link power efficiency, two test chips have been implemented. The first one describes a quad-lane, 6.4-7.2 Gb/s serial link receiver prototype using a forwarded clock architecture. A novel phase deskew scheme using injection-locked ring oscillators (ILRO) is proposed that achieves greater than one UI of phase shift for multiple clock phases, eliminating phase rotation and interpolation required in conventional architectures. Each receiver, optimized for power efficiency, consists of a low-power linear equalizer, four offset-cancelled quantizers for 1:4 demultiplexing, and an injection-locked ring oscillator coupled to a low-voltage swing, global clock distribution. Measurement results show a 6.4-7.2Gb/s data rate with BER < 10⁻¹² across 14 cm of PCB, and an 8Gb/s data rate through 4cm of PCB. Designed in a 1.2V, 90nm CMOS process, the ILRO achieves a wide tuning range from 1.6-2.6GHz. The total area of each receiver is 0.0174mm², resulting in a measured power efficiency of 0.6mW/Gb/s.
Improving upon the first test chip, a second test chip for 8Gb/s forwarded clock serial link receivers exploits a low-power super-harmonic injection-locked ring oscillator for symmetric multi-phase local clock generation and deskewing. Further power reduction is achieved by designing most of the receiver circuits in the near-threshold region (0.6V supply), with the exception of only the global clock buffer, test buffers and synthesized digital test circuits at nominal 1V supply. At the architectural level, a 1:10 direct demultiplexing rate is chosen to achieve low supply operation by exploiting high-parallelism. Fabricated in 65nm CMOS technology, two receiver prototypes are integrated in this test chip, one without and the other with front-end boot-strapped S/Hs. Including the amortized power of global clock distribution, the proposed serial link receivers consume 1.3mW and 2mW respectively at 8Gb/s input data rate, achieving a power efficiency of 0.163mW/Gb/s and 0.25mW/Gb/s. Measurement results show both receivers achieve BER < 10⁻¹² across a 20-cm FR4 PCB channel.Graduation date: 2012
21
Ku, Chien Chun, and 辜建竣. "Arbitrary Output Power Ratio One Section Branch Line Design." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/ympumh.
Full textAbstract:
碩士國立勤益科技大學
電子工程系
105
In this paper, an arbitrary output power ratio one section branch line coupler is proposed. Based on two symmetry planes and the circuit analysis, using Mathematica software as the formula to derive the auxiliary program, the scattering parameters of the structure are deduced. By giving some physical parameters we have deduced the equal electrical length of any output power ratio branch line coupler, fixed electrical length of any output power ratio branch line coupler, equal transmission line impedance value of any output ratio branch line coupler, and fixed transmission line impedance value of any output ratio branch line coupler. All circuits were simulated by the EM simulation softwares, the output power ratio at working frequency can be applied to any ratio of the output power of the demand, the fabricted circuits were measured by the vector network analyzer, and the simulated and measured results are in good agreement at working frequency. The circuit design can be applied to different center frequency, easy to fabricate, and has significantly cost reduction in circuit fabrication.
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Lai, Xi-Song, and 賴溪松. "Tandem and route diversity system design on 20GHz band radio relay links in Taiwan." Thesis, 1986. http://ndltd.ncl.edu.tw/handle/41316677086828795565.
Full text
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HSU, SHIH-ANG, and 許世昂. "Designs of High Power Ratio Dividers Using Left-Handed Transmission Line Transformers." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/75y88e.
Full textAbstract:
碩士國立高雄大學
電機工程學系碩博士班
105
In general, high power ratio unequal Wilkinson power divider needs high characteristic impedance quarter-wavelength transformer. However, high impedance microstrip quarter-wavelength transformer is not easily implemented. Each of the proposed high power ratio unequal power dividers uses left-handed transmission line transformer which has -90° phase delay to avoid the usage of high impedance quarter-wavelength transformer. In order to achieve impedance match and isolation design, an equivalent 270° impedance transformer can be designed between isolation resistor and input port of each proposed divider. In this study, the equivalent 270° impedance transformer is realized by multi-T-shaped, multi-π-shaped, or a uniform impedance transmission line transformer.
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Han, Guoxiang. "High-Performance Reconfigurable Radio-Frequency Integrated-Circuit Receiver Architectures for Concurrent Signal Reception." Thesis, 2021. https://doi.org/10.7916/d8-2d6f-tb91.
Full textAbstract:
The ever-increasing demand for wireless throughput requires modern handset receivers to aggregate signals from multiple non-contiguously allocated RF carriers. This poses significant receiver design challenges, including concurrent signal reception, RF input interface, out-of-band (OB) linearity, and suppression of spurious responses. Commercial solutions use external antenna switches and off-chip RF multiplexers to provide non-tunable, narrowband filtering and impedance matching. The RF signal is then divided into separate signal chains, each with a dedicated receiver for signal reception. Although this solution allows the selection of any carrier combinations supported by the available RF filters, as the number of aggregation band combinations increases, the scale of the passive front-end module grows rapidly, leading to increased system complexity, extra signal loss, and degraded performance.
This thesis presents the design and implementation of two receiver architectures that support reconfigurable operations and flexible, concurrent reception from two inter-band carriers with a tuned RF interface. We first present a multi-branch receiver with modulated mixer clocks (MMC). It unifies the functions of single-carrier and dual-carrier reception, as well as compressive-sampling spectrum scanning into a single architecture. With continuous-wave-modulated mixer clocks, the receiver supports concurrent reception from two distinct bands and realizes tuned impedance matching that greatly improves the OB linearity. With pseudo-noise-modulated mixer clocks, the receiver supports spectrum scanning. Disabling modulation reverts the receiver into a single-carrier receiver with good OB linearity. The 65nm CMOS prototype is developed that operates from 300 to 1300MHz and offers 2.7dB minimum NF, -1.3dBm B1dB, and +8.0dBm IIP3 for single-carrier reception. Concurrent dual-carrier reception is demonstrated that offers -8.4dBm B1dB and sub-6dB NF with the two carriers separated from 200 to 600MHz apart. For spectrum scanning, the receiver achieves a 66dB dynamic range with -75dBm sensitivity over a 630MHz RF span. In addition, a discussion of the higher-order MMC technique is included to improve the receiver’s spurious and noise performance by suppressing the higher-order responses and mitigating the noise-folding effect.
Next, we present an IF-filterless, double-conversion receiver. The concurrent, narrowband RF interface is realized with two layers of passive mixing in its mixer-first branches, which translate the low-pass, baseband impedance twice to two distinct bands and improve the OB linearity. Branches with DDS-modulated LNTAs for multi-phase, switched-Gm mixing offer rejection of spurious responses and improved noise performance. The 65nm CMOS prototype is developed that operates from 100 to 1200MHz. For single-carrier reception, the receiver delivers 4.8dB minimum NF, +7.9dBm B1dB, and +22.8dBm IIP3. For concurrent signal reception, two arbitrarily-allocated RF carriers, separated from 200 to 600MHz apart, can be received concurrently. The receiver delivers a +1.9dBm B1dB and supports 8-/16-phase DDS modulation with a 30dB spurious rejection across its operating range. In addition, a theoretical study of a modified, mixer-first branch is included. By re-arranging the connections of the baseband termination resistors, the baseband noise can be fully cancelled, thus improving the receiver’s noise performance.
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Teng, Chi-Huan, and 鄧跡寰. "Design of the Microstrip Couplers with Arbitrary Power Ratio and Microstrip Bandpass Filter with the Stepped Coupled Line." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/65560166977257394692.
Full textAbstract:
碩士國立中正大學
電機工程研究所
101
This paper presents two designs. First, a novel design equations and examples of the modified arbitrary power ratio microstrip tandem coupler are presented. In order to obtain a wide passband, couplers with triple poles at the return loss are proposed. Compared to the conventional couplers such as Lange couplers and parallel coupled line couplers, high impedance transmission lines and narrow coupling gaps are not required for the proposed microstrip coupler. In terms of measured results, there is a wide bandwidth of more than 70%. Moreover, good agreement between theoretical predication and measurement validates our proposed structure. In the second design, a novel wide passband microstrip bandpass filter with broader stopbands is provided. The proposed bandpass filters is composed of the stepped coupled line and two short-circuited stubs. Each stage of electrical length of the stepped coupled line has been optimized and cascaded together for harmonic suppression. Moreover, the stepped coupled line with weak–strong–weak coupling results in a wide stopband. Furthermore, with short-circuited stubs connected at the input/output port, there is a steeper passband skirt and broader passband. In addition, the agreement between theoretical prediction and measurement validates our proposed structure.