Energy Efficiency in Communications and Networks

The topic of "Energy Efficiency in Communications and Networks" attracts growing attention due to economical and environmental reasons. The amount of power consumed by information and communication technologies (ICT) is rapidly increasing, as well as the energy bill of service providers. According to a number of studies, ICT alone is responsible for a percentage which varies from 2% to 10% of the world power consumption. Thus, driving rising cost and sustainability concerns about the energy footprint of the IT infrastructure. Energy-efficiency is an aspect that until recently was only considered for battery driven devices. Today we see energy-efficiency becoming a pervasive issue that will need to be considered in all technology areas from device technology to systems management. This book is seeking to provide a compilation of novel research contributions on hardware design, architectures, protocols and algorithms that will improve the energy efficiency of communication devices and networks and lead to a more energy proportional technology infrastructure

INTERMITTENTLY CONNECTED DELAY-TOLERANT WIRELESS SENSOR NETWORKS

Intermittently Connected Delay-Tolerant Wireless Sensor Networks (ICDT-WSNs), a branch of Wireless Sensor Networks (WSNs), have features of WSNs and the intermittent connectivity of Opportunistic Networks. The applications of ICDT-WSNs are increasing in recent years; however, the communication protocols suitable for this category of networks often fall short. Most of the existing communication protocols are designed for either WSNs or Opportunistic Networks with sufficient resources and tend to be inadequate for direct use in ICDT-WSNs. In this dissertation, we study ICDT-WSNs from the perspective of the characteristics, chal- lenges and possible solutions. A high-level overview of ICDT-WSNs is given, followed by a study of existing work and our solutions to address the problems of routing, flow control, error control, and storage management. The proposed solutions utilize the utility level of nodes and the connectedness of a network. In addition to the protocols for information transmissions to specific destinations, we also propose efficient mechanisms for information dissemination to arbitrary destinations. The study shows that our proposed solutions can achieve better performance than other state of the art communication protocols without sacrificing energy efficiency

A co-design-based reliable low-latency and energy-efficient transmission protocol for uwsns

Recently, underwater wireless sensor networks (UWSNs) have been considered as a powerful technique for many applications. However, acoustic communications in UWSNs bring in huge QoS issues for time-critical applications. Additionally, excessive control packets and multiple copies during the data transmission process exacerbate this challenge. Faced with these problems, we propose a reliable low-latency and energy-efficient transmission protocol for dense 3D underwater wireless sensor networks to improve the QoS of UWSNs. The proposed protocol exploits fewer control packets and reduces data-packet copies effectively through the co-design of routing and media access control (MAC) protocols. The co-design method is divided into two steps. First, the number of handshakes in the MAC process will be greatly reduced via our forwarding-set routing strategy under the guarantee of reliability. Second, with the help of information from the MAC process, network-update messages can be used to replace control packages through mobility prediction when choosing a route. Simulation results show that the proposed protocol has a considerably higher reliability, and lower latency and energy consumption in comparison with existing transmission protocols for a dense underwater wireless sensor network.This work was supported by the National Natural Science Foundation of China (NSFC) (Grant Nos. U19A2061, 61772228 and 61902143), National key research and development program of China (Grant No. 2017YFC1502306)

Internet of Underwater Things and Big Marine Data Analytics -- A Comprehensive Survey

The Internet of Underwater Things (IoUT) is an emerging communication ecosystem developed for connecting underwater objects in maritime and underwater environments. The IoUT technology is intricately linked with intelligent boats and ships, smart shores and oceans, automatic marine transportations, positioning and navigation, underwater exploration, disaster prediction and prevention, as well as with intelligent monitoring and security. The IoUT has an influence at various scales ranging from a small scientific observatory, to a midsized harbor, and to covering global oceanic trade. The network architecture of IoUT is intrinsically heterogeneous and should be sufficiently resilient to operate in harsh environments. This creates major challenges in terms of underwater communications, whilst relying on limited energy resources. Additionally, the volume, velocity, and variety of data produced by sensors, hydrophones, and cameras in IoUT is enormous, giving rise to the concept of Big Marine Data (BMD), which has its own processing challenges. Hence, conventional data processing techniques will falter, and bespoke Machine Learning (ML) solutions have to be employed for automatically learning the specific BMD behavior and features facilitating knowledge extraction and decision support. The motivation of this paper is to comprehensively survey the IoUT, BMD, and their synthesis. It also aims for exploring the nexus of BMD with ML. We set out from underwater data collection and then discuss the family of IoUT data communication techniques with an emphasis on the state-of-the-art research challenges. We then review the suite of ML solutions suitable for BMD handling and analytics. We treat the subject deductively from an educational perspective, critically appraising the material surveyed.Comment: 54 pages, 11 figures, 19 tables, IEEE Communications Surveys & Tutorials, peer-reviewed academic journa

Analysis of MAC Strategies for Underwater Acoustic Networks

En esta tesis presentamos los protocolos MAC diseñados para redes acústicas subacuáticas, clasificándolos en amplias categorías, proporcionando técnicas de medición de rendimiento y análisis comparativo para seleccionar el mejor algoritmo MAC para aplicaciones específicas. Floor Acquisition Multiple Access (FAMA) es un protocolo MAC que se propuso para redes acústicas submarinas como medio para resolver los problemas de terminales ocultos y expuestos. Una versión modificada, Slotted FAMA, tenía como objetivo proporcionar ahorros de energía mediante el uso de ranuras de tiempo, eliminando así la necesidad de paquetes de control excesivamente largos en FAMA. Sin embargo, se ha observado que, debido al alto retraso de propagación en estas redes, el coste de perder un ACK es muy alto y tiene un impacto significativo en el rendimiento. Los mecanismos MultiACK y EarlyACK han sido analizados para el protocolo MACA, para mejorar su eficiencia. El mecanismo MultiACK aumenta la probabilidad de recibir al menos un paquete ACK al responder con un tren de paquetes ACK, mientras que el mecanismo EarlyACK evita la repetición de todo el ciclo de contención y transmisión de datos RTS / CTS enviando un ACK temprano. En esta investigación se presenta un análisis matemático de las dos variantes, los mecanismos MultiACK y EarlyACK, en Slotted FAMA. La investigación incluye las expresiones analíticas modificadas así como los resultados numéricos. Las simulaciones se llevaron a cabo utilizando ns-3. Los resultados han sido probados y validados utilizando Excel y MATLAB. La evaluación del rendimiento de S-FAMA con dos variantes mostró un factor de mejora del 65,05% en la probabilidad de recibir un ACK correctamente utilizando el mecanismo MultiACK y del 60,58% en la prevención de la repetición del ciclo completo, con EarlyACK. El impacto de este factor de mejora en el retardo, el tamaño del paquete de datos y el rendimiento también se analiza. La energía de transmisión desperdiciada y consumida en los mecanismos MultiACK y EarlyACK se analizan y comparan con S-FAMA. El rendimiento se ha evaluado, alcanzando una mejora en ambos casos, en comparación con S-FAMA. Estos mecanismos tendrán una utilidad práctica en caso de pérdida de ACK, al ahorrar energía y tiempo en períodos críticos. Fecha de lectura de Tesis Doctoral: 28 septiembre 2018.Esta tesis presenta una investigación sobre los protocolos MAC utilizados en la comunicación subacuática para explorar el mundo submarino. Los protocolos MAC ayudan en el acceso al medio compartido y la recopilación de datos de los océanos, para monitorizar el clima y la contaminación, la prevención de catástrofes, la navegación asistida, la vigilancia estratégica y la exploración de los recursos minerales. Esta investigación beneficiará a sectores como las industrias militares, de petróleo y gas, pesquerías, compañías de instrumentación subacuática, organismos de investigación, etc. El protocolo MAC afecta la vida útil de las redes inalámbricas de sensores. La eficiencia energética de las redes acústicas submarinas se ve gravemente afectada por las propiedades típicas de la propagación de las ondas acústicas. Los largos retrasos de propagación y las colisiones de paquetes de datos dificultan la transmisión de los paquetes de datos, que contienen información útil para que los usuarios realicen tareas de supervisión colectivas. El objetivo de este estudio es proponer nuevos mecanismos para protocolos MAC diseñados para funcionar en redes acústicas submarinas, con el propósito de mejorar su rendimiento. Para alcanzar ese objetivo es necesario realizar un análisis comparativo de los protocolos existentes. Lo que además sienta un procedimiento metodológicamente correcto para realizar esa comparación. Como la comunicación subacuática depende de ondas acústicas, en el diseño de los protocolos de MAC submarinos surgen varios desafíos como latencia prolongada, ancho de banda limitado, largas demoras en la propagación, grandes tasas de error de bit, pérdidas momentáneas en las conexiones, severo efecto multicamino y desvanecimientos. Los protocolos MAC terrestres, si se implementan directamente, funcionarán de manera ineficiente

A Priority-based Fair Queuing (PFQ) Model for Wireless Healthcare System

Healthcare is a very active research area, primarily due to the increase in the elderly population that leads to increasing number of emergency situations that require urgent actions. In recent years some of wireless networked medical devices were equipped with different sensors to measure and report on vital signs of patient remotely. The most important sensors are Heart Beat Rate (ECG), Pressure and Glucose sensors. However, the strict requirements and real-time nature of medical applications dictate the extreme importance and need for appropriate Quality of Service (QoS), fast and accurate delivery of a patient’s measurements in reliable e-Health ecosystem. As the elderly age and older adult population is increasing (65 years and above) due to the advancement in medicine and medical care in the last two decades; high QoS and reliable e-health ecosystem has become a major challenge in Healthcare especially for patients who require continuous monitoring and attention. Nevertheless, predictions have indicated that elderly population will be approximately 2 billion in developing countries by 2050 where availability of medical staff shall be unable to cope with this growth and emergency cases that need immediate intervention. On the other side, limitations in communication networks capacity, congestions and the humongous increase of devices, applications and IOT using the available communication networks add extra layer of challenges on E-health ecosystem such as time constraints, quality of measurements and signals reaching healthcare centres. Hence this research has tackled the delay and jitter parameters in E-health M2M wireless communication and succeeded in reducing them in comparison to current available models. The novelty of this research has succeeded in developing a new Priority Queuing model ‘’Priority Based-Fair Queuing’’ (PFQ) where a new priority level and concept of ‘’Patient’s Health Record’’ (PHR) has been developed and integrated with the Priority Parameters (PP) values of each sensor to add a second level of priority. The results and data analysis performed on the PFQ model under different scenarios simulating real M2M E-health environment have revealed that the PFQ has outperformed the results obtained from simulating the widely used current models such as First in First Out (FIFO) and Weight Fair Queuing (WFQ). PFQ model has improved transmission of ECG sensor data by decreasing delay and jitter in emergency cases by 83.32% and 75.88% respectively in comparison to FIFO and 46.65% and 60.13% with respect to WFQ model. Similarly, in pressure sensor the improvements were 82.41% and 71.5% and 68.43% and 73.36% in comparison to FIFO and WFQ respectively. Data transmission were also improved in the Glucose sensor by 80.85% and 64.7% and 92.1% and 83.17% in comparison to FIFO and WFQ respectively. However, non-emergency cases data transmission using PFQ model was negatively impacted and scored higher rates than FIFO and WFQ since PFQ tends to give higher priority to emergency cases. Thus, a derivative from the PFQ model has been developed to create a new version namely “Priority Based-Fair Queuing-Tolerated Delay” (PFQ-TD) to balance the data transmission between emergency and non-emergency cases where tolerated delay in emergency cases has been considered. PFQ-TD has succeeded in balancing fairly this issue and reducing the total average delay and jitter of emergency and non-emergency cases in all sensors and keep them within the acceptable allowable standards. PFQ-TD has improved the overall average delay and jitter in emergency and non-emergency cases among all sensors by 41% and 84% respectively in comparison to PFQ model