Mobile and Wireless Communications

Mobile and Wireless Communications have been one of the major revolutions of the late twentieth century. We are witnessing a very fast growth in these technologies where mobile and wireless communications have become so ubiquitous in our society and indispensable for our daily lives. The relentless demand for higher data rates with better quality of services to comply with state-of-the art applications has revolutionized the wireless communication field and led to the emergence of new technologies such as Bluetooth, WiFi, Wimax, Ultra wideband, OFDMA. Moreover, the market tendency confirms that this revolution is not ready to stop in the foreseen future. Mobile and wireless communications applications cover diverse areas including entertainment, industrialist, biomedical, medicine, safety and security, and others, which definitely are improving our daily life. Wireless communication network is a multidisciplinary field addressing different aspects raging from theoretical analysis, system architecture design, and hardware and software implementations. While different new applications are requiring higher data rates and better quality of service and prolonging the mobile battery life, new development and advanced research studies and systems and circuits designs are necessary to keep pace with the market requirements. This book covers the most advanced research and development topics in mobile and wireless communication networks. It is divided into two parts with a total of thirty-four stand-alone chapters covering various areas of wireless communications of special topics including: physical layer and network layer, access methods and scheduling, techniques and technologies, antenna and amplifier design, integrated circuit design, applications and systems. These chapters present advanced novel and cutting-edge results and development related to wireless communication offering the readers the opportunity to enrich their knowledge in specific topics as well as to explore the whole field of rapidly emerging mobile and wireless networks. We hope that this book will be useful for students, researchers and practitioners in their research studies

Caso de estudio de comunicaciones seguras sobre redes móviles <i>ad hoc</i>

En este trabajo se presenta el estudio de un caso de integración de una MANET, desplegada en una zona remota, a una red de infraestructura. La finalidad principal es la de proporcionar, a los nodos de la red ad hoc, acceso “seguro” a un servidor de la red de infraestructura, sin comprometer recursos como ancho de banda y energía que son limitados en la zona de despliegue. Para ello, se implemento un escenario de pruebas que comprende el despliegue de una MANET en zona remota y la integración de la misma a una red de infraestructura a través de la red celular. Sobre el escenario propuesto se establecieron canales de comunicación extremo a extremo, entre un nodo de la MANET y un servidor de infraestructura. Inicialmente, se realizaron pruebas inyectando tráfico de datos sobre un canal “no seguro” para obtener valores de referencia para latencia, throughput y consumo de energía. Luego, se efectuaron las mismas pruebas utilizando canales de comunicación “seguros” configurados sobre protocolos IPSEC y SSL/TLS. Los resultados obtenidos utilizando canales “seguros” fueron comparados con los valores de referencia para determinar las diferencias de consumo de recursos. Las desviaciones que surgieron de estas comparaciones, permitieron: - Establecer el consumo adicional de recursos generado por el uso de protocolos seguros. - Realizar un estudio comparativo de rendimiento, entre diferentes configuraciones de protocolos de seguridad. - Determinar que protocolo seguro se adapta mejor a este tipo de entornos.Facultad de Informátic

Cell search algorithms for WCDMA systems

Wideband Code Division Multiple Access (WCDMA) system uses orthogonal channelization codes to distinguish physical channels in a base station, while base stations are identified by different downlink scrambling codes. User equipments (UEs) must achieve synchronization to the downlink scrambling code before decoding any messages from base stations. The process of searching for a base station and synchronization to the downlink scrambling code is often referred to as cell search. The performance of cell search has a significant impact on a UE's switch-on delay, and thus it is very important to UE design. The goal of designing a cell search algorithm is to achieve a balance between speed, accuracy and complexity. A basic three-stage cell search procedure has been defined by 3GPP. It employs synchronization channels and the common pilot channel to facilitate a fast cell search. This cell search scheme only works well if there is no frequency offset between a base station's transmitter and a UE's receiver and if sampling timing is perfect on a UE. In practice, however, imperfection of oscillator in a UE may cause a big frequency error as well as clock error. It usually results in phase rotations and sampling timing drifts, which may degrade cell search performance significantly. Some advanced cell search algorithms have been proposed for mitigating impacts of frequency error or clock error. However, there is no much discussion on comprehensive solutions that can deal with the two negative impacts at the same time. In this thesis, we propose an algorithm that considers both frequency error and clock error. A fast and accurate cell search with a relatively low level of complexity is achieved. The algorithms are based on a combination of four existing enhanced cell search algorithms that are designed for a toleration of either frequency error or clock error. We first introduce the 3GPP-defined cell search algorithm as a basis. Then the four existing enhanced algorithms, PSD (partial symbol de-spreading), DDCC (differential detection with coherent combining), STS-1 (serial test in stage-1) and RSPT (random sampling per trial) are presented. Next, we propose four possible combinations of the existing algorithms: PSD+STS-1, PSD+RSPT, DDCC+STS-1 and DDCC+RSPT. Through extensive computer simulations, we find the DDCC+RSPT algorithm to be the best one. It is superior to other combinations and also outperforms any existing algorithm in terms of acquisition time, detection probability and complexity. Therefore, it is highly recommended for practical uses

A Unified Multi-Functional Dynamic Spectrum Access Framework: Tutorial, Theory and Multi-GHz Wideband Testbed

Dynamic spectrum access is a must-have ingredient for future sensors that are ideally cognitive. The goal of this paper is a tutorial treatment of wideband cognitive radio and radar—a convergence of (1) algorithms survey, (2) hardware platforms survey, (3) challenges for multi-function (radar/communications) multi-GHz front end, (4) compressed sensing for multi-GHz waveforms—revolutionary A/D, (5) machine learning for cognitive radio/radar, (6) quickest detection, and (7) overlay/underlay cognitive radio waveforms. One focus of this paper is to address the multi-GHz front end, which is the challenge for the next-generation cognitive sensors. The unifying theme of this paper is to spell out the convergence for cognitive radio, radar, and anti-jamming. Moore’s law drives the system functions into digital parts. From a system viewpoint, this paper gives the first comprehensive treatment for the functions and the challenges of this multi-function (wideband) system. This paper brings together the inter-disciplinary knowledge

Convergence of packet communications over the evolved mobile networks; signal processing and protocol performance

In this thesis, the convergence of packet communications over the evolved mobile networks is studied. The Long Term Evolution (LTE) process is dominating the Third Generation Partnership Project (3GPP) in order to bring technologies to the markets in the spirit of continuous innovation. The global markets of mobile information services are growing towards the Mobile Information Society. The thesis begins with the principles and theories of the multiple-access transmission schemes, transmitter receiver techniques and signal processing algorithms. Next, packet communications and Internet protocols are referred from the IETF standards with the characteristics of mobile communications in the focus. The mobile network architecture and protocols bind together the evolved packet system of Internet communications to the radio access network technologies. Specifics of the traffic models are shortly visited for their statistical meaning in the radio performance analysis. Radio resource management algorithms and protocols, also procedures, are covered addressing their relevance for the system performance. Throughout these Chapters, the commonalities and differentiators of the WCDMA, WCDMA/HSPA and LTE are covered. The main outcome of the thesis is the performance analysis of the LTE technology beginning from the early discoveries to the analysis of various system features and finally converging to an extensive system analysis campaign. The system performance is analysed with the characteristics of voice over the Internet and best effort traffic of the Internet. These traffic classes represent the majority of the mobile traffic in the converged packet networks, and yet they are simple enough for a fair and generic analysis of technologies. The thesis consists of publications and inventions created by the author that proposed several improvements to the 3G technologies towards the LTE. In the system analysis, the LTE showed by the factor of at least 2.5 to 3 times higher system measures compared to the WCDMA/HSPA reference. The WCDMA/HSPA networks are currently available with over 400 million subscribers and showing increasing growth, in the meanwhile the first LTE roll-outs are scheduled to begin in 2010. Sophisticated 3G LTE mobile devices are expected to appear fluently for all consumer segments in the following years

A Survey on Security and Privacy of 5G Technologies: Potential Solutions, Recent Advancements, and Future Directions

Security has become the primary concern in many telecommunications industries today as risks can have high consequences. Especially, as the core and enable technologies will be associated with 5G network, the confidential information will move at all layers in future wireless systems. Several incidents revealed that the hazard encountered by an infected wireless network, not only affects the security and privacy concerns, but also impedes the complex dynamics of the communications ecosystem. Consequently, the complexity and strength of security attacks have increased in the recent past making the detection or prevention of sabotage a global challenge. From the security and privacy perspectives, this paper presents a comprehensive detail on the core and enabling technologies, which are used to build the 5G security model; network softwarization security, PHY (Physical) layer security and 5G privacy concerns, among others. Additionally, the paper includes discussion on security monitoring and management of 5G networks. This paper also evaluates the related security measures and standards of core 5G technologies by resorting to different standardization bodies and provide a brief overview of 5G standardization security forces. Furthermore, the key projects of international significance, in line with the security concerns of 5G and beyond are also presented. Finally, a future directions and open challenges section has included to encourage future research.European CommissionNational Research Tomsk Polytechnic UniversityUpdate citation details during checkdate report - A

Identification of Technologies for Provision of Future Aeronautical Communications

This report describes the process, findings, and recommendations of the second of three phases of the Future Communications Study (FCS) technology investigation conducted by NASA Glenn Research Center and ITT Advanced Engineering & Sciences Division for the Federal Aviation Administration (FAA). The FCS is a collaborative research effort between the FAA and Eurocontrol to address frequency congestion and spectrum depletion for safety critical airground communications. The goal of the technology investigation is to identify technologies that can support the longterm aeronautical mobile communication operating concept. A derived set of evaluation criteria traceable to the operating concept document is presented. An adaptation of the analytical hierarchy process is described and recommended for selecting candidates for detailed evaluation. Evaluations of a subset of technologies brought forward from the prescreening process are provided. Five of those are identified as candidates with the highest potential for continental airspace solutions in L-band (P-34, W-CDMA, LDL, B-VHF, and E-TDMA). Additional technologies are identified as best performers in the unique environments of remote/oceanic airspace in the satellite bands (Inmarsat SBB and a custom satellite solution) and the airport flight domain in C-band (802.16e). Details of the evaluation criteria, channel models, and the technology evaluations are provided in appendixes