Overview and Goals Wireless communication technologies are undergoing rapid advancements. The last few years have experienced a steep growth in research in the area of wireless sensor networks (WSNs). In WSNs, communication takes place with the help of spatially distributedautonomoussensornodesequippedtosensespeci?cinformation. WSNs, especially the ones that have gained much popularity in the recent years, are, ty- cally, ad hoc in nature and they inherit many characteristics/features of wireless ad hoc networks such as the ability for infrastructure-less setup, minimal or no reliance on network planning, and the ability of the nodes to self-organize and self-con?gure without the involvement of a centralized network manager, router, access point, or a switch. These features help to set up WSNs fast in situations where there is no existing network setup or in times when setting up a ?xed infrastructure network is considered infeasible, for example, in times of emergency or during relief - erations. WSNs ?nd a variety of applications in both the military and the civilian population worldwide such as in cases of enemy intrusion in the battle?eld, object tracking, habitat monitoring, patient monitoring, ?re detection, and so on. Even though sensor networks have emerged to be attractive and they hold great promises for our future, there are several challenges that need to be addressed. Some of the well-known challenges are attributed to issues relating to coverage and deployment, scalability, quality-of-service, size, computational power, energy ef?ciency, and security.

Wireless Sensor Networks: Theory and Practice for Deployment addresses WSNs deployment, a mandatory and critical step in the process of developing WSNs solutions for real-life applications. The authors address simple approaches to deploy static WSNs, then exploring more sophisticated approaches to deploy mobile WSNs. Featuring detailed investigations of deployment-related issues such as deployment cost, coverage, connectivity, sensors reliability, and harsh deployment environments, this book will equip you with the basics and an advanced view of both the theoretical and practical aspects, along with knowledge of the guidelines for WSNs deployment.

Wireless Communications Systems Design provides the basic knowledge and methodology for wireless communications design. The book mainly focuses on a broadband wireless communication system based on OFDM/OFDMA system because it is widely used in the modern wireless communication system. It is divided into three parts: wireless communication theory (part I), wireless communication block design (part II), and wireless communication block integration (part III). Written by an expert with various experience in system design (standards, research and development)

This book features various, ultra low energy, variability resilient SRAM circuit design techniques for wireless sensor network applications. Conventional SRAM design targets area efficiency and high performance at the increased cost of energy consumption, making it unsuitable for computation-intensive sensor node applications. This book, therefore, guides the reader through different techniques at the circuit level for reducing energy consumption and increasing the variability resilience. It includes a detailed review of the most efficient circuit design techniques and trade-offs, introduces new memory architecture techniques, sense amplifier circuits and voltage optimization methods for reducing the impact of variability for the advanced technology nodes. "

Combining information on the most important and related technologies in the mobile communications field, this two book package gives the engineer a concise, complete and authoritative introduction to LTE and SAE and The Evolved Packet Core. Written by experts who played a leading role in the development of the standards, this package gives insight into the 'how' and 'why', enabling the professional engineer to implement the technologies that are central to the mobile broadband revolution. Includes details of the standards and technologies with 160 new pages: LTE radio interface architecture, LTE physical layer and LTE access procedures Contains three brand new chapters on LTE: Transmission Procedures, Flexible Bandwidth and LTE Evolution, plus expanded details on the physical layer (total LTE content is 270 pages) Examines the latest developments in the evolution of LTE into IMT-Advanced, the next stage of 3G Evolution Gives clear explanations of the role of OFDM and MIMO technologies in HSPA and LTE Outlines the System Architecture Evolution (SAE) supporting LTE and HSPA evolution Up-to-date coverage of SAE including the latest standards development Easily accessible overview of the architecture and concepts defined by SAE Thorough description of the Evolved Packet Core for LTE, fixed and other wireless accesses Comprehensive explanation of SAE key concepts, security and Quality-of-Service Covers potential service and operator scenarios including interworking with existing 3GPP and 3GPP2 systems Detailed walkthrough of network entities, protocols and procedures Written by established experts in the SAE standardization process, all of whom have extensive experience and understanding of its goals, history and vision

Now that Apple has introduced the GameKit framework to its iOS SDK, you can integrate Game Center features directly into your iPhone and iPad apps. This concise cookbook shows you how it's done, with 18 targeted recipes for adding leaderboards, user authentication, achievements, multiplayer games, and many other features.

How do you display players' scores and achievements? How do you create Game Center accounts and add friends? Each recipe in this book includes a simple code solution you can put to work immediately, along with a detailed discussion that offers insight into why and how the recipe works.

Recipes include techniques to: Set up Game Center for an iOS App Use block objects and Grand Central Dispatch to write Game Center apps Authenticate a local player in Game Center Use iTunes Connect to create leaderboards and achievements Retrieve leaderboard and achievement information programmatically Handle players' state changes in multiplayer games

Adaptive signal processing (ASP) and iterative signal processing (ISP) are important techniques in improving receiver performance in communication systems. Using examples from practical transceiver designs, this 2006 book describes the fundamental theory and practical aspects of both methods, providing a link between the two where possible. The first two parts of the book deal with ASP and ISP respectively, each in the context of receiver design over intersymbol interference (ISI) channels. In the third part, the applications of ASP and ISP to receiver design in other interference-limited channels, including CDMA and MIMO, are considered; the author attempts to illustrate how the two techniques can be used to solve problems in channels that have inherent uncertainty. Containing illustrations and worked examples, this book is suitable for graduate students and researchers in electrical engineering, as well as practitioners in the telecommunications industry.

The result of decades of research and international project experience, Multimedia Communications and Networking provides authoritative insight into recent developments in multimedia, digital communications, and networking services and technologies. Supplying you with the required foundation in these areas, it illustrates the means that will allow for improved digital communications and networks. The book starts with a review of the fundamental concepts, requirements, and constraints in networks and telecommunications. It describes channel disturbances that can hinder system performance-including noise, attenuation, distortion, and interferences-and provides transmission techniques for mitigating these limitations. Analyzing both cable and wireless transmission mediums, the book describes the network protocol architecture concept and includes coverage of twisted pairs, coaxial and optical fiber cables, wireless propagation, satellite communications, and terrestrial microwave systems. Facilitating the understanding required to participate in the development of current and next generation networks and services, this comprehensive reference: Examines the range of network interconnections and WAN/MAN technologies, including synchronous optical networks (SONET), synchronous digital hierarchy (SDH), and third and next generation cellular systems (3G and 4G) Describes local area network (LAN) theory and technology, including data link layers and virtual LANs Explores network and transport layers, such as addressing, routing protocols, and IPv4 and IPv6 algorithms Covers TCP/IP services and applications Investigates different authentication and cryptographic systems, including digital signature, SSL, TLS, IPSEC, and public key infrastructure Walking you through the planning, design, and development of multimedia, telecommunications, and networking systems, the book provides a quick and easy way to develop and refine the skills required in the field. It clearly explains the principles and corresponding techniques you need to know to implement network security. The many examples and end-of-chapter questions also make it suitable for undergraduate and graduate-level computer science and electrical engineering courses.

The high level of technical detail included in standards specifications can make it difficult to find the correlation between the standard specifications and the theoretical results. This book aims to cover both of these elements to give accessible information and support to readers. It explains the current and future trends on communication theory and shows how these developments are implemented in contemporary wireless communication standards.

Examining modulation, coding and multiple access techniques, the book is divided into two major sections to cover these functions. The two-stage approach first treats the basics of modulation and coding theory before highlighting how these concepts are defined and implemented in modern wireless communication systems. Part 1 is devoted to the presentation of main L1 procedures and methods including modulation, coding, channel equalization and multiple access techniques. In Part 2, the uses of these procedures and methods in the wide range of wireless communication standards including WLAN, WiMax, WCDMA, HSPA, LTE and cdma2000 are considered.An essential study of the implementation of modulation and coding techniques in modern standards of wireless communication Bridges the gap between the modulation coding theory and the wireless communications standards material Divided into two parts to systematically tackle the topic - the first part develops techniques which are then applied and tailored to real world systems in the second part Covers special aspects of coding theory and how these can be effectively applied to improve the performance of wireless communications systems

Covers IoT-cloud convergence with a focus on complex industrial IoT case studies Discusses the broad background of IoT-cloud convergence architectures and their fundamentals along with resource provisioning mechanisms Emphasizes the use of context in developing context aware IoT solutions Presents a novel C-model that explains the IoT application development phases Discusses a simplified convergence model that depicts the role of cloud in an IoT application

With this groundbreaking text, discover how wireless artificial intelligence (AI) can be used to determine position at centimeter level, sense motion and vital signs, and identify events and people. Using a highly innovative approach that employs existing wireless equipment and signal processing techniques to turn multipaths into virtual antennas, combined with the physical principle of time reversal and machine learning, it covers fundamental theory, extensive experimental results, and real practical use cases developed for products and applications. Topics explored include indoor positioning and tracking, wireless sensing and analytics, wireless power transfer and energy efficiency, 5G and next-generation communications, and the connection of large numbers of heterogeneous IoT devices of various bandwidths and capabilities. Demo videos accompanying the book online enhance understanding of these topics. Providing a unified framework for wireless AI, this is an excellent text for graduate students, researchers, and professionals working in wireless sensing, positioning, IoT, machine learning, signal processing and wireless communications.

THE NETWORK PROFESSIONAL'S GUIDE TO PLANNING, DESIGNING, AND DEPLOYING 5G TRANSPORT NETWORKS As 5G transforms mobile usage and services, network professionals will need to significantly evolve their transport network architectures towards greater sophistication and stronger integration with radio networks, and facilitate transition towards cloud-native 5G mobile core. Until now, however, most 5G guides have foregrounded RF/radio and mobile core innovations, not its implications for data networks. A Network Architect's Guide to 5G fills the gap, giving network architects, designers, and engineers essential knowledge for designing and planning their own 5G networks. Drawing on decades of experience with global service providers and enterprise networks, the authors illuminate new and evolving network technologies necessary for building 5G-capable networks, such as segment routing, network slicing, timing and synchronization, edge computing, distributed data centers, integration with public cloud, and more. They explain how 5G blurs boundaries between mobile core, radio access, and transport, as well as the changes in the composition of a traditional cell site with the adoption of Open and Virtualized RAN resulting in a transition to mobile xHaul. Every chapter builds on earlier coverage, culminating in a "big picture" presentation of a complete 5G network design. Understand the evolution of mobile technologies over the generation leading to 5G's foundational concepts and principles. Explore 5G changes to Radio Access Networks (RAN), the Mobile Core, Mobile Transport, and the need for tighter integration between them. Use Segment Routing to architect simplified, SDN-capable networks, and enable network slicing for 5G. Rethink transport design to incorporate Far-Edge, Edge, and public-cloud based data centers augmenting centralized DCs to support distributed peering and Multi-access Edge Compute. Provide guidance to meet the criteria and requirements for various aspects of Fronthaul, Midhaul, and Backhaul architecture, such as transport protocol evaluation, latency consideration, routing design, QoS modeling, network device selection, and more. Forge a cohesive 5G network architecture by combining mobile communications principles with advanced transport technologies.

Over the last two decades, fieldbus has totally revolutionized the way communication takes place in the fields of process control, automation, and manufacturing industries. Recent introduction of real-time fieldbuses has opened up its application in multi-axis motor control and other time-critical applications. Fieldbus is designed to ensure easy interoperability, smarter network designs, increased data availability, and lessened stress on the design aspects of safety protocols. This second edition of Fieldbus and Networking in Process Automation discusses the different facets of fieldbus technology including design, wiring, installation, and commissioning as well as safety aspects in hostile application areas. The book: * Explains basic communication principles and networking-a must for understanding fieldbuses * Considers the advantages and shortcomings of individual fieldbuses * Provides a broad spectrum of different fieldbuses used in both process control and manufacturing industries in a precise and to-the-point manner * Introduces Common Industrial Protocol (CIP), EtherNet/IP, EtherCAT, SERCOS III, Powerlink, and Profinet IRT, which are mostly sought after in control and automation fields * Discusses hard real-time communication in a succinct manner-so essential in today's multi-axis motor control systems * Updates and streamlines the extra details from the original book to make it more concise and reader friendly Sunit Kumar Sen, a member of IET, holds advanced degrees from St Xavier's College and University of Calcutta, both in Kolkata, India. He was an ex-professor in the Instrumentation Engineering section of the Department of Applied Physics, University of Calcutta, and taught courses in digital electronics, communication, industrial instrumentation, microprocessors, electrical networks, and fieldbuses. He was the head of the Department of Applied Physics and University Science Instrumentation Center from 2008-2010 at the University of Calcutta. Previously, he was assistant manager, instrumentation (oprn.) at the Bokaro Steel Plant, Jharkhand, India, under the Steel Authority of India (SAIL). He has already written four books in the areas of instrumentation, microprocessors, and industrial automation technologies. He has been published in approximately 70 national and international journals and conferences.

Wireless communications have become indispensable part of our lives. The book deals with the security of such wireless communication. The technological background of these applications have been presented in detail. Special emphasis has been laid on the IEEE 802.11x-standards that have been developed for this technology. A major part of the book is devoted to security risks, encryption and authentication. Checklists have been provided to help IT administrators and security officers to achieve the maximum possible security in their installations, when using wireless technology. This is the second edition of the book. The updates include the latest the IEEE 802.11-standard, an updated chapter on PDA, the increased relevance of smart phones and tablets, widespread use of WLAN with increased security risks.

Comprehensive and timely, Cloud Computing: Concepts and Technologies offers a thorough and detailed description of cloud computing concepts, architectures, and technologies, along with guidance on the best ways to understand and implement them. It covers the multi-core architectures, distributed and parallel computing models, virtualization, cloud developments, workload and Service-Level-Agreements (SLA) in cloud, workload management. Further, resource management issues in cloud with regard to resource provisioning, resource allocation, resource mapping and resource adaptation, ethical, non-ethical and security issues in cloud are followed by discussion of open challenges and future directions. This book gives students a comprehensive overview of the latest technologies and guidance on cloud computing, and is ideal for those studying the subject in specific modules or advanced courses. It is designed in twelve chapters followed by laboratory setups and experiments. Each chapter has multiple choice questions with answers, as well as review questions and critical thinking questions. The chapters are practically-focused, meaning that the information will also be relevant and useful for professionals wanting an overview of the topic.

This book discusses, for the first time, wireless power transfer in the ocean environment. Topics covered include power electronic techniques, advanced control strategies, as well as classic and emerging applications such as smart ocean energy systems and wireless power transfer and charging of underwater autonomous vehicles. Emerging research topics are presented, along with methodologies, approaches, and industrial development of intelligent and energy-efficient techniques. Apart from the basic principles with an emphasis on inductive power transfer and mathematical analysis, the book discusses the emerging implementation for underwater wireless power transfer such as energy encryption, power and data transfer through common links, and secured data- and cyber-security. Specifically, the book comprehensively introduces significant discussions on UWPT coil theoretical and experimental analysis in seawater, optimal design, and intelligent controls. For example, since fast communication is not viable in an underwater environment, the proposed book discusses Maximum Power Efficiency Tracking (MPET) control, which achieves a maximum power efficiency (>85%) without communication or feedback from the transmitting side of the UWPT system. A k-nearest-neighbors-based machine learning approach is used to estimate the coupling coefficiency between the coils. This machine learning-based intelligent control method can offer important guidance for graduate students, academic researchers, and industrial engineers who want to understand the working principles and realize the developing trends in underwater wireless power transfer. Finally, the book includes details on the modeling and design of a smart ocean energy system--a new type of power harvesting system designed to convert ocean energy into electricity, which has the capability of making underwater wireless power connections with distributed marine devices.

This Springerbrief presents a deep reinforcement learning approach to wireless systems to improve system performance. Particularly, deep reinforcement learning approach is used in cache-enabled opportunistic interference alignment wireless networks and mobile social networks. Simulation results with different network parameters are presented to show the effectiveness of the proposed scheme. There is a phenomenal burst of research activities in artificial intelligence, deep reinforcement learning and wireless systems. Deep reinforcement learning has been successfully used to solve many practical problems. For example, Google DeepMind adopts this method on several artificial intelligent projects with big data (e.g., AlphaGo), and gets quite good results.. Graduate students in electrical and computer engineering, as well as computer science will find this brief useful as a study guide. Researchers, engineers, computer scientists, programmers, and policy makers will also find this brief to be a useful tool.

Continuous Signals and Systems with MATLAB (R) offers broad, detailed, and focused comprehensive coverage of continuous linear systems, based on basic mathematical principles. It presents many solved problems from various engineering disciplines using analytical tools as well as MATLAB. This book is intended primarily for undergraduate junior and senior electrical, mechanical, aeronautical, and aerospace engineering students. Practicing engineers will also find this book useful. This book is ideal for use in a one-semester course in continuous linear systems where the instructor can easily cover all of the chapters. Each chapter presents numerous examples that illustrate each concept. Most of the worked-out examples are first solved analytically, and then solved using MATLAB in a clear and understandable fashion. This book concentrates on explaining the subject matter with easy-to-follow mathematical development and numerous solved examples. The book covers traditional topics and includes an extensive coverage of state-space representation and analysis. The reader does not need to be fluent in MATLAB because the examples are presented in a self-explanatory way.

Wireless and mobile communications have grown exponentially. The average individual now possesses a minimum of two smart mobile devices. The consistent advancement of mobile devices feeds the ever-growing appetite for faster bandwidth, uninterrupted connectivity, applications to fulfill the needs of consumers and businesses, and security for all of this information. Mobile Devices: Tools and Technologies provides readers at all levels of technical expertise with an understanding of mobile device concepts, application development processes, networking and infrastructure, and security methods. This book is organized into four sections, with chapters contributed by engineers with extensive real-world experience in the mobile and wireless field. The first section discusses the current mobile device landscape, including the latest technology innovations, personal and business use trends, and mobile operating systems and applications. The second section focuses on the application development process, from strategy and process through the development phases, to production and launch. This section covers both Android and iOS application development. In the third section, the authors explore mobile access standards, network types, and infrastructure components. This section also covers proximity communications standards, including Bluetooth, NFC, and RFID. The book concludes with a look at mobile device security, including mobile encryption methods, wireless security levels, and corporate security and workforce management strategies. Throughout the book, the contributors illustrate proven best practices and methodologies using real-world case studies drawn from their extensive experiences with mobile software and infrastructures for enterprise customers.

Building Wireless Sensor Networks: Theoretical and Practical Perspectives presents the state of the art of wireless sensor networks (WSNs) from fundamental concepts to cutting-edge technologies. Focusing on WSN topics ideal for undergraduate and postgraduate curricula, this book: Provides essential knowledge of the contemporary theory and practice of wireless sensor networking Describes WSN architectures, protocols, and operating systems Details the routing and data aggregation algorithms Addresses WSN security and energy efficiency Includes sample programs for experimentation The book offers overarching coverage of this exciting field, filling a critical gap in the existing literature.

This SpringerBrief addresses the main security concerns for smart grid, e.g., the privacy of electricity consumers, the exchanged messages integrity and confidentiality, the authenticity of participated parties, and the false data injection attacks. Moreover, the authors demonstrate in detail the various proposed techniques to secure the smart grid's different communication networks and preserve the privacy of the involved. Over many years, power grid has generated electricity from central generators and distributed it in one direction from the generation stations to end-users; also, information is one directional so that the grid's control center doesn't get enough information about customers' requirements and consequently can't prevent electricity losses. So, the electricity grid is merged with information and communication technology to form smart grid. The main target of this incorporation is to connect different parties of power grid to exchange information about grid conditions and customers' requirements, and consequently, improve the reliability and efficiency of electricity generation and distribution. That upgrade of the power grid exposes it to the cyber security threats that the communication networks suffer from, such as malicious attacks to forge the electricity consumption readings or price, extract personal information for residential consumers, such as daily habits and life style, or attack some grid's resources and equipment availability using denial-of-service attacks. Also, novel threats are introduced in smart grid due to the power grid nature, such as false data injection attack, in which the adversary compromises several measurement units and injects false information about the grid conditions that mislead the grid's control center to make wrong decisions for the grid and consequently impact on its stability and efficiency.

The operational theme permeating most definitions of the IoT concept, is the wireless communication of networked objects, in particular, smart sensing devices and machines, exchanging data a la Internet. In this book, a detailed look is taken at the fundamental principles of devices and techniques whose exploitation will facilitate the development of compact, power-efficient, autonomous, smart, networked sensing nodes underlying and encompassing the emerging IoT era. The book provides an understanding of nanoelectromechanical quantum circuits and systems (NEMX), as exemplified by firstly the uncovering of their origins, impetus and motivation, and secondly by developing an understanding of their device physics, including, the topics of actuation, mechanical vibration and sensing. Next the fundamentals of key devices, namely, MEMS/NEMS switches, varactors and resonators are covered, including a wide range of implementations. The book then looks at their energy supply via energy harvesting, as derived from wireless energy and mechanical vibrations. Finally, after an introduction to the fundamentals of IoT networks and nodes, the book concludes with an exploration of how the NEMX components are encroaching in a variety of emerging IoT applications.

We are always surrounded by electromagnetic waves and fields of various spectra. This book explains basic electromagnetic theory with the help of design formulations i.e. mathematical background on antennas along with experimentations, which has made this book unique. The main purpose of this book is to embed mathematical EM theory of dielectric resonator antennas with experimental validation so that understanding of concepts takes place. Initially, basic understanding of philosophy of dielectric resonators has been discussed, then it is supported with mathematical modeling and later same is implemented with its prototype model along with experimentations. The modes theory gives important analysis on currents distribution, impedance analysis and radiation pattern in DRA. Circular polarization can built signal robustness, case studies on circular polarization has been included. Equivalent RLC circuit concept has been introduced. Challenges of switching from microwave to terahertz has been briefly discussed. Nano DRA will revolutionize the wireless technology. Nano DRA ,Terahertz DRA and Quantum DRA have analyzed and studied.

Get to grips with the principles and practice of signal processing used in mobile communications systems. Focusing particularly on speech, video, and modem signal processing, pioneering experts employ a detailed, top-down analytical approach to outline the network architectures and protocol structures of multiple generations of mobile communications systems, identify the logical ranges where media and radio signal processing occur, and analyze the procedures for capturing, compressing, transmitting, and presenting media. Chapters are uniquely structured to show the evolution of network architectures and technical elements between generations up to and including 5G, with an emphasis on maximizing service quality and network capacity through re-using existing infrastructure and technologies. Implementation examples and data taken from commercial networks provide an in-depth insight into the operation of real mobile communications systems, including GSM, cdma2000, W-CDMA, LTE, and LTE-A, making this a practical, hands-on guide for both practicing engineers and graduate students in wireless communications.

Mobile Applications Development with Android: Technologies and Algorithms presents advanced techniques for mobile app development, and addresses recent developments in mobile technologies and wireless networks. The book covers advanced algorithms, embedded systems, novel mobile app architecture, and mobile cloud computing paradigms.

Divided into three sections, the book explores three major dimensions in the current mobile app development domain. The first section describes mobile app design and development skills, including a quick start on using Java to run an Android application on a real phone. It also introduces 2D graphics and UI design, as well as multimedia in Android mobile apps.

The second part of the book delves into advanced mobile app optimization, including an overview of mobile embedded systems and architecture. Data storage in Android, mobile optimization by dynamic programming, and mobile optimization by loop scheduling are also covered. The last section of the book looks at emerging technologies, including mobile cloud computing, advanced techniques using Big Data, and mobile Big Data storage.

About the Authors

Meikang Qiu is an Associate Professor of Computer Science at Pace University, and an adjunct professor at Columbia University. He is an IEEE/ACM Senior Member, as well as Chair of the IEEE STC (Special Technical Community) on Smart Computing. He is an Associate Editor of a dozen of journals including IEEE Transactions on Computers and IEEE Transactions on Cloud Computing. He has published 320+ peer-reviewed journal/conference papers and won 10+ Best Paper Awards.

Wenyun Dai is pursuing his PhD at Pace University. His research interests include high performance computing, mobile data privacy, resource management optimization, cloud computing, and mobile networking. His paper about mobile app privacy has been published in IEEE Transactions on Computers.

Keke Gai is pursuing his PhD at Pace University. He has published over 60 peer-reviewed journal or conference papers, and has received three IEEE Best Paper Awards. His research interests include cloud computing, cyber security, combinatorial optimization, business process modeling, enterprise architecture, and Internet computing.

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Table of Contents

Overview of Mobile Apps and Mobile Interface. Mobile Embedded System and Architecture. Introduction of Android Framework, Key Concepts, User Interface, and Multimedia Deployment. Network Management in Mobile Cloud Computing and Adaptive Resource Allocations. 2-D Graphics and Mobile Image Processing Techniques. Mobile Optimization by Dynamic Programming. Big Data and Hybrid Memory Implementations. Exploring Mobile Hardware and Software Coding Techniques. Secure Bluetooth Connection and Near Field Communication. Data Storage, data security, and advanced data protection techniques. Efficient Data Synchronization on Mobile Devices. Mobile Apps on Wearable Devices.