Optimizing performance and energy efficiency of group communication and internet of things in cognitive radio networks

Data traffic in the wireless networks has grown at an unprecedented rate. While traditional wireless networks follow fixed spectrum assignment, spectrum scarcity problem becomes a major challenge in the next generations of wireless networks. Cognitive radio is a promising candidate technology that can mitigate this critical challenge by allowing dynamic spectrum access and increasing the spectrum utilization. As users and data traffic demands increases, more efficient communication methods to support communication in general, and group communication in particular, are needed. On the other hand, limited battery for the wireless network device in general makes it a bottleneck for enhancing the performance of wireless networks. In this thesis, the problem of optimizing the performance of group communication in CRNs is studied. Moreover, energy efficient and wireless-powered group communication in CRNs are considered. Additionally, a cognitive mobile base station and a cognitive UAV are proposed for the purpose of optimizing energy transfer and data dissemination, respectively. First, a multi-objective optimization for many-to-many communication in CRNs is considered. Given a many-to-many communication request, the goal is to support message routing from each user in the many-to-many group to each other. The objectives are minimizing the delay and the number of used links and maximizing data rate. The network is modeled using a multi-layer hyper graph, and the secondary users\u27 transmission is scheduled after establishing the conflict graph. Due to the difficulty of solving the problem optimally, a modified version of an Ant Colony meta-heuristic algorithm is employed to solve the problem. Additionally, energy efficient multicast communication in CRNs is introduced while considering directional and omnidirectional antennas. The multicast service is supported such that the total energy consumption of data transmission and channel switching is minimized. The optimization problem is formulated as a Mixed Integer Linear Program (MILP), and a heuristic algorithm is proposed to solve the problem in polynomial time. Second, wireless-powered machine-to-machine multicast communication in cellular networks is studied. To incentivize Internet of Things (IoT) devices to participate in forwarding the multicast messages, each IoT device participates in messages forwarding receives Radio Frequency (RF) energy form Energy Transmitters (ET) not less than the amount of energy used for messages forwarding. The objective is to minimize total transferred energy by the ETs. The problem is formulated mathematically as a Mixed Integer Nonlinear Program (MINLP), and a Generalized Bender Decomposition with Successive Convex Programming (GBD-SCP) algorithm is introduced to get an approximate solution since there is no efficient way in general to solve the problem optimally. Moreover, another algorithm, Constraints Decomposition with SCP and Binary Variable Relaxation (CDR), is proposed to get an approximate solution in a more efficient way. On the other hand, a cognitive mobile station base is proposed to transfer data and energy to a group of IoT devices underlying a primary network. Total energy consumed by the cognitive base station in its mobility, data transmission and energy transfer is minimized. Moreover, the cognitive base station adjusts its location and transmission power and transmission schedule such that data and energy demands are supported within a certain tolerable time and the primary users are protected from harmful interference. Finally, we consider a cognitive Unmanned Aerial Vehicle (UAV) to disseminate data to IoT devices. The UAV senses the spectrum and finds an idle channel, then it predicts when the corresponding primary user of the selected channel becomes active based on the elapsed time of the off period. Accordingly, it starts its transmission at the beginning of the next frame right after finding the channel is idle. Moreover, it decides the number of the consecutive transmission slots that it will use such that the number of interfering slots to the corresponding primary user does not exceed a certain threshold. A mathematical problem is formulated to maximize the minimum number of bits received by the IoT devices. A successive convex programming-based algorithm is used to get a solution for the problem in an efficiency way. It is shown that the used algorithm converges to a Kuhn Tucker point

Wireless Sensor Networks

The aim of this book is to present few important issues of WSNs, from the application, design and technology points of view. The book highlights power efficient design issues related to wireless sensor networks, the existing WSN applications, and discusses the research efforts being undertaken in this field which put the reader in good pace to be able to understand more advanced research and make a contribution in this field for themselves. It is believed that this book serves as a comprehensive reference for graduate and undergraduate senior students who seek to learn latest development in wireless sensor networks

High Performance Wireless Sensor-Actuator Networks for Industrial Internet of Things

Wireless Sensor-Actuator Networks (WSANs) enable cost-effective communication for Industrial Internet of Things (IIoT). To achieve predictability and reliability demanded by industrial applications, industrial wireless standards (e.g., WirelessHART) incorporate a set of unique features such as a centralized management architecture, Time Slotted Channel Hopping (TSCH), and conservative channel selection. However, those features also incur significant degradation in performance, efficiency, and agility. To overcome these key limitations of existing industrial wireless technologies, this thesis work develops and empirically evaluates a suite of novel network protocols and algorithms. The primary contributions of this thesis are four-fold. (1) We first build an experimental testbed realizing key features of the WirelessHART protocol stack, and perform a series of empirical studies to uncover the limitations and potential improvements of existing network features. (2) We then investigate the impacts of the industrial WSAN protocol’s channel selection mechanism on routing and real-time performance, and present new channel and link selection strategies that improve route diversity and real-time performance. (3) To further enhance performance, we propose and design conservative channel reuse, a novel approach to support concurrent transmissions in a same wireless channel while maintaining a high degree of reliability. (4) Lastly, to address the limitation of the centralized architecture in handling network dynamics, we develop REACT, a Reliable, Efficient, and Adaptive Control Plane for centralized network management. REACT is designed to reduce the latency and energy cost of network reconfiguration by incorporating a reconfiguration planner to reduce a rescheduling cost, and an update engine providing efficient and reliable mechanisms to support schedule reconfiguration. All the network protocols and algorithms developed in this thesis have been empirically evaluated on the wireless testbed. This thesis represents a step toward next-generation IIoT for industrial automation that demands high-performance and agile wireless communication

Design and evaluation of high-performance packet switching schemes

The design of high-performance packet switches is essential to efficiently handle the exponential growth of data traffic in the next generation Internet. Shared-memory-based packet switches are known to provide the best possible delay-throughput performance and the lowest packet-loss rate compared with packet switches using other buffering strategies. However, scalability of shared-memory-based switching systems has been restricted by high memory bandwidth requirements, segregation of memory space and centralized control of switching functions that causes the switch performance to degrade as a shared-memory switch is grown in size. The new class of sliding-window based packet switches are known to overcome these problems associated with shared-memory switches. This thesis presents different schemes proposed earlier by Dr. Kumar for use in the sliding-window switch to allocate self-routing parameters. Comparative performance of these schemes have been evaluated in this thesis. The results show the scalability of the switch that can be achieved with different parameter assignment schemes. It is shown that not all assignment schemes have same performance. With appropriate assignment scheme, it is possible to achieve very high throughput-performance and switch size for sliding-window switches

Systems integration using Siemens\u27 PC based automation technology

Manufacturing Systems Integration is the progressive linking and combination of the various components of the system to merge their functional and technical characteristics into a comprehensive interoperable unit. It requires one to work with different hardware and software. There are a number of vendors providing a large number of products. Integrating these varieties of products provides a greater value than the sum of the value provided by the individual products. What hinders the effective integration of these components is the diversity in the design and the use of these products. Systems Integration is eased by well-established standards in data communication, programming languages, application development environments and computer operating systems. Many vendors have attempted to come up with standards that are relatively open. However, when one has to integrate data among multiple vendors\u27 architecture, a new set of challenges emerge. The Siemens\u27 PC-based automation technology is an emerging technology that appears to provide robust architecture for integrating all elements of the manufacturing environment. Applications ranging from simple control to distributed control and full-fledged Manufacturing Execution Systems can be developed using Siemens\u27 architecture. The primary focus of this applied research work is to develop a Manufacturing Execution System to control a flexible manufacturing system using Siemens PC-based automation technology. This technology is implemented in a Flexible Manufacturing cell named the CAMCELL. The CAMCELL consists of two CNC machining centers, assembly robots, and a vision system, all of which are interlinked by a material handling system. The software architecture of the CAMCELL is based on NIST\u27s five level hierarchy, discussed briefly in the report. Specifically it contains functional modules for order entry, scheduling and routing. In addition to these functional modules, there are various support modules such as order entry module, scheduler, router etc, two of which named the Inquire and the Pallet Controller that are implemented in this study. Siemens\u27 Step 7 and WTNCC software are used for the control and monitoring of the cell

Performance analysis on multi-dimensional optical routing networks.

Zhang Yu.Thesis (M.Phil.)--Chinese University of Hong Kong, 2002.Includes bibliographical references (leaves 67-72).Abstracts in English and Chinese.Chapter 1 --- Introduction --- p.1Chapter 1.1 --- Overview of Optical Networking --- p.1Chapter 1.2 --- Mechanism in Optical Routing Networks --- p.3Chapter 1.3 --- Related Work on Optical Routing Networks --- p.4Chapter 1.4 --- The Motivation of This Thesis --- p.7Chapter 1.5 --- Thesis Structure --- p.8Chapter 2 --- Technologies for Multi-dimensional Optical Routing Networks --- p.10Chapter 2.1 --- Background --- p.10Chapter 2.2 --- Multi-fiber WDM Networks --- p.11Chapter 2.2.1 --- Phased-Array-Based WDM Device --- p.11Chapter 2.2.2 --- Wavelength-tunable lasers --- p.11Chapter 2.2.3 --- Tunable optical Filter --- p.12Chapter 2.2.4 --- Wavelength Converter --- p.13Chapter 2.3 --- OCDM/WDM --- p.16Chapter 2.3.1 --- Optical En/Decoder --- p.17Chapter 2.3.2 --- Optical Switch --- p.18Chapter 2.3.3 --- Optical Code Conversion --- p.18Chapter 2.4 --- OTDM/WDM --- p.21Chapter 2.4.1 --- Fast Optical Switch --- p.22Chapter 2.4.2 --- Optical Time Slot Interchanger (OTSI) --- p.22Chapter 2.5 --- Conclusion --- p.23Chapter 3 --- Performance of Code/Wavelength Routing Networks --- p.24Chapter 3.1 --- Background --- p.24Chapter 3.2 --- Reconfiguration Capability --- p.25Chapter 3.3 --- Analytic Models --- p.27Chapter 3.3.1 --- Trunk Switched Model --- p.27Chapter 3.3.2 --- Assumptions --- p.28Chapter 3.3.3 --- Blocking of the Paths with Various Configurations --- p.29Chapter 3.4 --- Numerical Results --- p.34Chapter 3.5 --- Conclusion --- p.35Chapter 4 --- Decomposition Schemes --- p.40Chapter 4.1 --- Introduction --- p.40Chapter 4.2 --- Inclusive Converted Networks --- p.41Chapter 4.3 --- Decompositions --- p.43Chapter 4.3.1 --- Spatial Decomposition (S.D.) --- p.43Chapter 4.3.2 --- Dimensional Decomposition (D.D.) --- p.44Chapter 4.3.3 --- Iterative Decompositions --- p.45Chapter 4.4 --- Conclusion --- p.46Chapter 5 --- Performance of Multi-Dimensional Optical Routing Networks --- p.48Chapter 5.1 --- Homogeneous Trunk Switched Networks --- p.48Chapter 5.2 --- Analytical Model --- p.49Chapter 5.3 --- Utilization Gain --- p.53Chapter 5.4 --- Conversion Gain --- p.54Chapter 5.5 --- Comparison on the Utilization Gain by Multiplexing and by Conversion --- p.56Chapter 5.6 --- Conclusion --- p.57Chapter 6 --- Conclusion --- p.65Chapter 6.1 --- Summary of the Thesis --- p.65Chapter 6.2 --- Future Work --- p.6

Enhancements of G3-PLC technology for smart-home/building applications

To enable the smart grid concept, it is fundamental to consider the in-home/building context where, beside the conventional home networking services, home automation and smart energy management services have to be offered. In this paper, we consider the in-home/building scenario, for which we propose a convergent network architecture to enhance the performance of the narrowband power line communication (PLC) G3-PLC technology through its integration with an Ethernet-based network. To this end, we define the protocols characterizing the network modules, namely, switches and routers, which allow for integrating the G3-PLC with Ethernet devices. Since Ethernet represents a convergent standard for many communication devices, by adding this functionality to G3-PLC, interconnectivity with other heterogeneous nodes can be offered. Furthermore, since the G3-PLC medium access control layer is based on a carrier sense multiple access scheme, its performance decreases when the number of network nodes contending for the channel increases. Therefore, we evaluate the network performance when an optimized time division multiple access scheme is adopted. The proposed convergent network architecture has been implemented in the OMNeT++ network simulator

A critical analysis of research potential, challenges and future directives in industrial wireless sensor networks

In recent years, Industrial Wireless Sensor Networks (IWSNs) have emerged as an important research theme with applications spanning a wide range of industries including automation, monitoring, process control, feedback systems and automotive. Wide scope of IWSNs applications ranging from small production units, large oil and gas industries to nuclear fission control, enables a fast-paced research in this field. Though IWSNs offer advantages of low cost, flexibility, scalability, self-healing, easy deployment and reformation, yet they pose certain limitations on available potential and introduce challenges on multiple fronts due to their susceptibility to highly complex and uncertain industrial environments. In this paper a detailed discussion on design objectives, challenges and solutions, for IWSNs, are presented. A careful evaluation of industrial systems, deadlines and possible hazards in industrial atmosphere are discussed. The paper also presents a thorough review of the existing standards and industrial protocols and gives a critical evaluation of potential of these standards and protocols along with a detailed discussion on available hardware platforms, specific industrial energy harvesting techniques and their capabilities. The paper lists main service providers for IWSNs solutions and gives insight of future trends and research gaps in the field of IWSNs