Cooperative Radio Communications for Green Smart Environments

The demand for mobile connectivity is continuously increasing, and by 2020 Mobile and Wireless Communications will serve not only very dense populations of mobile phones and nomadic computers, but also the expected multiplicity of devices and sensors located in machines, vehicles, health systems and city infrastructures. Future Mobile Networks are then faced with many new scenarios and use cases, which will load the networks with different data traffic patterns, in new or shared spectrum bands, creating new specific requirements. This book addresses both the techniques to model, analyse and optimise the radio links and transmission systems in such scenarios, together with the most advanced radio access, resource management and mobile networking technologies. This text summarises the work performed by more than 500 researchers from more than 120 institutions in Europe, America and Asia, from both academia and industries, within the framework of the COST IC1004 Action on "Cooperative Radio Communications for Green and Smart Environments". The book will have appeal to graduates and researchers in the Radio Communications area, and also to engineers working in the Wireless industry. Topics discussed in this book include: • Radio waves propagation phenomena in diverse urban, indoor, vehicular and body environments• Measurements, characterization, and modelling of radio channels beyond 4G networks• Key issues in Vehicle (V2X) communication• Wireless Body Area Networks, including specific Radio Channel Models for WBANs• Energy efficiency and resource management enhancements in Radio Access Networks• Definitions and models for the virtualised and cloud RAN architectures• Advances on feasible indoor localization and tracking techniques• Recent findings and innovations in antenna systems for communications• Physical Layer Network Coding for next generation wireless systems• Methods and techniques for MIMO Over the Air (OTA) testin

Cooperative Radio Communications for Green Smart Environments

The demand for mobile connectivity is continuously increasing, and by 2020 Mobile and Wireless Communications will serve not only very dense populations of mobile phones and nomadic computers, but also the expected multiplicity of devices and sensors located in machines, vehicles, health systems and city infrastructures. Future Mobile Networks are then faced with many new scenarios and use cases, which will load the networks with different data traffic patterns, in new or shared spectrum bands, creating new specific requirements. This book addresses both the techniques to model, analyse and optimise the radio links and transmission systems in such scenarios, together with the most advanced radio access, resource management and mobile networking technologies. This text summarises the work performed by more than 500 researchers from more than 120 institutions in Europe, America and Asia, from both academia and industries, within the framework of the COST IC1004 Action on "Cooperative Radio Communications for Green and Smart Environments". The book will have appeal to graduates and researchers in the Radio Communications area, and also to engineers working in the Wireless industry. Topics discussed in this book include: • Radio waves propagation phenomena in diverse urban, indoor, vehicular and body environments• Measurements, characterization, and modelling of radio channels beyond 4G networks• Key issues in Vehicle (V2X) communication• Wireless Body Area Networks, including specific Radio Channel Models for WBANs• Energy efficiency and resource management enhancements in Radio Access Networks• Definitions and models for the virtualised and cloud RAN architectures• Advances on feasible indoor localization and tracking techniques• Recent findings and innovations in antenna systems for communications• Physical Layer Network Coding for next generation wireless systems• Methods and techniques for MIMO Over the Air (OTA) testin

Design, Modeling, and Analysis for MAC Protocols in Ultra-wideband Networks

Ultra-wideband (UWB) is an appealing transmission technology for short-range, bandwidth demanded wireless communications. With the data rate of several hundred megabits per second, UWB demonstrates great potential in supporting multimedia streams such as high-definition television (HDTV), voice over Internet Protocol (VoIP), and console gaming in office or home networks, known as the wireless personal area network (WPAN). While vast research effort has been made on the physical layer issues of UWB, the corresponding medium access control (MAC) protocols that exploit UWB technology have not been well developed. Given an extremely wide bandwidth of UWB, a fundamental problem on how to manage multiple users to efficiently utilize the bandwidth is a MAC design issue. Without explicitly considering the physical properties of UWB, existing MAC protocols are not optimized for UWB-based networks. In addition, the limited processing capability of UWB devices poses challenges to the design of low-complexity MAC protocols. In this thesis, we comprehensively investigate the MAC protocols for UWB networks. The objective is to link the physical characteristics of UWB with the MAC protocols to fully exploit its advantage. We consider two themes: centralized and distributed UWB networks. For centralized networks, the most critical issue surrounding the MAC protocol is the resource allocation with fairness and quality of service (QoS) provisioning. We address this issue by breaking down into two scenarios: homogeneous and heterogeneous network configurations. In the homogeneous case, users have the same bandwidth requirement, and the objective of resource allocation is to maximize the network throughput. In the heterogeneous case, users have different bandwidth requirements, and the objective of resource allocation is to provide differentiated services. For both design objectives, the optimal scheduling problem is NP-hard. Our contributions lie in the development of low-complexity scheduling algorithms that fully exploit the characteristics of UWB. For distributed networks, the MAC becomes node-based problems, rather than link-based problems as in centralized networks. Each node either contends for channel access or reserves transmission opportunity through negotiation. We investigate two representative protocols that have been adopted in the WiMedia specification for future UWB-based WPANs. One is a contention-based protocol called prioritized channel access (PCA), which employs the same mechanisms as the enhanced distributed channel access (EDCA) in IEEE 802.11e for providing differentiated services. The other is a reservation-based protocol called distributed reservation protocol (DRP), which allows time slots to be reserved in a distributed manner. Our goal is to identify the capabilities of these two protocols in supporting multimedia applications for UWB networks. To achieve this, we develop analytical models and conduct detailed analysis for respective protocols. The proposed analytical models have several merits. They are accurate and provide close-form expressions with low computational effort. Through a cross-layer approach, our analytical models can capture the near-realistic protocol behaviors, thus useful insights into the protocol can be obtained to improve or fine-tune the protocol operations. The proposed models can also be readily extended to incorporate more sophisticated considerations, which should benefit future UWB network design

Device-To-Device Wireless Communications

The main topic investigated in this thesis is related to characterization of the performance of D2D wireless networks. Given this broad objective, analytical framework models based on stochastic geometry have been proposed. One of them deals with the study of the coverage probability of both cellular networks and D2D networks whereas the others are related to dynamic mobility models in which the effects of blockages on the link lifetime have been studied. On the other hand, the experimental activity based on UWB using passive tags has been presented in which a localization system based on the ultra-wideband (UWB) technology and high-level architectures to improve the cyclists safety has been proposed

실내 환경에서 초광대역 채널에 미치는 인체의 영향

학위논문 (박사)-- 서울대학교 대학원 : 전기·컴퓨터공학부, 2015. 8. 김성철.In this dissertation, the effects of human body on Ultra Wideband (UWB) channel in indoor environments are represented. Unlike previous communication system, UWB system has a large bandwidth. This leads to interference to the other communication systems in the same frequency bands. This feature makes UWB system deployable in line-of-sight (LOS) and slightly cluttered non-line-of-sight (NLOS) environment in which the signal undergoes less attenuation. In these environments, the UWB channel largely depends on surroundings of a transmitter (Tx) and receiver (Rx) antennas. In indoor environments, a human body is a major factor that changes channel characteristics. This dissertation dealt with the effect of human body on the UWB channel in indoor environments. First, this dissertation addresses UWB channel variation depending on the number of people in indoor LOS environments. To assess variation of UWB channels, four environments which have different room sizes and wall structures are considered. During measurements, people did not move around, but were just sitting on their chair with small motion if necessary. Because the UWB system operates in a wide bandwidth compared to previous communication systems, it is necessary to understand the frequency correlation characteristics of UWB channels. We found the correlation coefficients between two frequency tones with an interval of 10MHz are smaller than about 0.5. In the dissertation, we deal with a distance-dependent path-loss model, a frequency-dependent path-loss model, and time dispersion parameters. To provide a general channel model, we obtained the linear regression model with population density for each parameter. Next, the dissertation considered a situation where either LOS path is not blocked or slightly blocked by human bodies as a Rx is shifted by small-scale (1λ) distance while a Tx is fixed. In this situation, we measure the small-scale amplitude statistics in the absence and presence of human bodies and propose a statistical model of the small-scale fading distribution. From the measurement data, we found the best fitted channel model among several typical theoretical distribution models such as Lognormal, Nakagami, and Weibull distributions, showing good agreement with the empirical channel data. In the last part of dissertation, we dealt with the performance analysis of impulse radio (IR) UWB system based on the proposed small-scale fading distribution and also compare the performance with the existing channel model. Due to the fine time resolution of UWB system, the system mainly uses a rake receiver which consists of a number of correlators that are sampled at the delays related to specific number of multipath components. The dissertation considers two types of rake receiver, selective combining (SC) and partial combing (PC) rake receiver. The standard channel model, IEEE 802.15.4a, shows the best bit-error-rate (BER) performance. But this model does not include the effect of human body. When the effect of human body is included on 802.15.4a model, the BER performance is deteriorated.Chapter 1 Introduction.............................................................1 1.1 UWB system................................................................................1 1.2 UWB channel standard model.....................................................2 1.2.1 IEEE 802.15.3a……....................................................................2 1.2.2 IEEE 802.15.4a……....................................................................2 1.3 Motivation……....................................................................................3 1.4 Dissertation Outline............................................................................5 Chapter 2 Modeling of UWB channel with Population density in indoor LOS Environments................... ...............................6 2.1 Introduction..................................................................................6 2.2 Measurement Methodology ........................................................8 2.2.1 Measurement System...................................................................8 2.2.2 Measurement Scenario.................................................................9 2.3 Frequency Correlation Coefficient of the Measured Channel Gains ................................................................................................12 2.4 Path-Loss Characteristics……………………………………..15 2.4.1 Empirical distance-dependent path-loss model.........................15 2.4.2 Empirical frequency-dependent path-loss model......................18 2.5 Time-Dispersion Parameters.....................................................22 2.6 Conclusion...………..................................................................26 Chapter 3 Human body Affected Small-Scale Fading for indoor UWB channel…….....................................................27 3.1 Introduction................................................................................27 3.2 Measurement Campaign………………………………………28 3.2.1 Measurement System………………………………................28 3.2.2 Measurement Scenario…...........................................................28 3.3 Statistical Modeling of Small-Scale Fading ………….…………35 3.4 Small-Scale Fading Distribution by Body………….…………37 3.5 Conclusions................................................................................48 Chapter 4 Performance Analysis of Rake receiver in IR-UWB system………………………………………………………49 4.1 Introduction................................................................................49 4.2 UWB Rake receiver…....….......................................................51 4.2.1 UWB Rake receiver structure... ………………........................51 4.2.2 Rake Receiver Type... ………………………..........................54 4.3 Channel models…………………………….............................56 4.3.1 801.15.4a UWB channel model ……………….......................56 4.3.2 People Shadowing Effect on UWB Channels...........................58 4.4 BER performance analysis.........................................................60 4.5 Conclusion..................................................................................66 Bibliography..........................................................................67 Abstract in Korean.................................................................70Docto

Practical implementation of a hybrid indoor localization system

Mestrado de dupla diplomação com a UTFPR - Universidade Tecnológica Federal do ParanáIndoor localization systems occupy a significant role to track objects during their life cycle, e.g., related to retail, logistics and mobile robotics. These positioning systems use several techniques and technologies to estimate the position of each object, and face several requirements such as position accuracy, security, coverage range, energy consumption and cost. This master thesis describes a real-world scenario implementation, based on Bluetooth Low Energy (BLE) beacons, evaluating a Hybrid Indoor Positioning System (H-IPS) that combines two RSSI-based approaches: Multilateration (MLT) and Fingerprinting (FP). The objective is to track a target node, assuming that the object follows a linear motion model. It was employed Kalman Filter (KF) to decrease the positioning errors of the MLT and FP techniques. Furthermore a Track-to-Track Fusion (TTF) is performed on the two KF outputs in order to maximize the performance. The results show that the accuracy of H-IPS overcomes the standalone FP in 21%, while the original MLT is outperformed in 52%. Finally, the proposed solution demonstrated a probability of error < 2 m of 80%, while the same probability for the FP and MLT are 56% and 20%, respectively.Os sistemas de localização de ambientes internos desempenham um papel importante na localização de objectos durante o seu ciclo de vida, como por exemplo os relacionados com o varejo, a logística e a robótica móvel. Estes sistemas de localização utilizam várias técnicas e tecnologias para estimar a posição de cada objecto, e possuem alguns critérios tais como precisão, segurança, alcance, consumo de energia e custo. Esta dissertação de mestrado descreve uma implementação num cenário real, baseada em Bluetooth Low Energy (BLE) beacons, avaliando um Sistema Híbrido de Posicionamento para Ambientes Internos (H-IPS, do inglês Hybrid Indoor Positioning System) que combina duas abordagens baseadas no Indicador de Intensidade do Sinal Recebido (RSSI, do inglês Received Signal Strength Indicator): Multilateração (MLT) e Fingerprinting (FP). O objectivo é localizar um nó alvo, assumindo que o objecto segue um modelo de movimento linear. Foi utilizado Filtro de Kalman (FK) para diminuir os erros de posicionamento do MLT e FP, além de aplicar uma fusão de vetores de estado nas duas saídas FK, a fim de maximizar o desempenho. Os resultados mostram que a precisão do H-IPS supera o FP original em 21%, enquanto que o MLT original tem um desempenho superior a 52%. Finalmente, a solução proposta apresentou uma probabilidade de erro de < 2 m de 80%, enquanto a mesma probabilidade para FP e MLT foi de 56% e 20%, respectivamente

Improved Ultra Wideband Communication System through Adaptive Modulation and Spatial Diversity

PhDAdvances in Multimedia communications have shown the need for high data rate wireless links over short distances. This is to enhance flexibility, accessibility, portability and mobility of devices in home and enterprise environment thereby making users more productive. In 2004, the WiMedia group proposed the Multiband Orthogonal Frequency Division Multiplex Ultra Wideband (MB-OFDM UWB) system with a target of delivering data rate of 480Mbps over 3 metres. However, by now no existing commercial UWB product can meet this proposed specification. The project aims to investigate the reason why UWB technology has failed to realise its potential by carrying out detailed analysis and to seek ways of solving the technical problems. Detailed system analyses were carried out on the UWB technology using a commercial UWB product and a MB-OFDM UWB Evaluation kit. UWB channel measurements of different scenarios were carried out in order to characterise both time varying and time invariant channels. The scenarios are the realistic environments where UWB devices are operating with human subjects in various movement patterns. It gives insight into the effects of human object blocking on the MB-OFDM system performance and estimates an acceptable feedback rate in a UWB time varying channel when implementing an adaptive modulation. The adaptive modulation was proposed and implemented in the MB-OFDM system model to demonstrate the improved Bit Error Rate (BER) performance. Modulating bits are varied across the sub-channels depending on the signal to noise ratio (SNR). Sub-channels experiencing severe fading employ lower or no bit-loading while sub-channels with little or no fading utilise higher bit-loading to maintain a constant system data rate. Spatial diversity was employed to exploit different properties of the radio channel to improve performance. Good diversity gain of two receiving diversity systems using maximal ratio combining and antenna selection techniques is demonstrated in the measurements with the different antenna orientations. An antenna selection circuit is designed and implemented working together with AT90CAP9 UWB Evaluation kit, verifying an improved performance of the UWB system in an indoor environment. The maximal ratio combining technique is also implemented and demonstrated to give a better system performance on a test bed after post-processing

UWB in 3D Indoor Positioning and Base Station Calibration

There are several technologies available for object locating and tracking in outdoor and indoor environments but performance requirements are getting tighter and precise object tracking is still largely an open challenge for researchers. Ultra wideband technology (UWB) has been identified as one of the most promising techniques to enhance a mobile node with accurate ranging and tracking capabilities. For indoor applications almost all positioning technologies require physical installation of fixed infrastructure. This infrastructure is usually expensive to deploy and maintain. The aim of this thesis is to improve the accessibility of the RF-positioning systems by lowering the configuration cost. Real time localisation and tracking systems (RTLS) based on RF technologies pose challenges especially for the deployment of positioning system over large areas or throughout buildings within a number of rooms. If calibration is done manually by providing information about the exact position of the base stations, the initial set-up is particularly time consuming and laborious. In this thesis a method for estimating the position and orientation (x, y, z, yaw, pitch and roll) of a base station of a real time localization system is presented. The algorithm uses two-dimensional Angle of Arrival information (i.e. azimuth and elevation measurements). This allows more inaccurate manual initial survey of the base stations and improves the final accuracy of the positioning. The thesis presents an implementation of the algorithm, simulations and empirical results. In the experiments, hardware and software procured from Ubisense was used. The Ubisense RTLS bases on UWB technology and utilises Angle of Arrival and Time Difference of Arrival techniques. Performance and functionality of the Ubisense RTLS were measured in various radio environments as well as the implementation of the calibration algorithm. Simulations and experiment studies showed that camera calibration method can be successfully adapted to position systems based on UWB technology and that the base stations can be calibrated in a sufficient accuracy. Because of more flexible calibration, the final positioning accuracy of the Ubisense system was as whole in average better.fi=Opinnäytetyö kokotekstinä PDF-muodossa.|en=Thesis fulltext in PDF format.|sv=Lärdomsprov tillgängligt som fulltext i PDF-format