Modified Token Based Congestion Control Scheme for Opportunistic Networks

To address congestion issues in Opportunistic Networks (OppNets) a modified token-based congestion control with adaptive forwarding mechanism is proposed. The mechanism allows the network nodes holding a valid token to inject message into the network or other neighboring node. At the point of congestion, the algorithm has the potential to redirect the traffic from more congested node to congestion free node for the purpose of effective resource utilization and fairness in the network. Tokens are evenly distributed throughout the network. Using opportunistic network environment (ONE) simulator we illustrate the performance of modified token-based congestion control algorithm, which results in reduction for messages, and network transit time due to congestion across all the scenarios considered. At different queue sizes of (QS-10, QS-20, QS-30 and QS-40), modified token based congestion control algorithm has 13.91%, 10.71%, 5.46%, and 4.22% respectively reduction in dropped messages. In addition, at greatest connected component values of 50%, 60%, 70% and 80%, modified token-based congestion control has 8.34%, 2.19%, 4.61%, and 7.63% respectively decrease in network transit time. These results are substantial because they indicate a reduction in both network storage as well as time

PROGRESSION TOWARDS CONTROLLING OF PACKET LOSS IN NETWORKS

Computer networks are intended to hold a certain amount of traffic with a suitable level of network performance.  Packets will undergo long queuing delays at congested nodes and perhaps packet loss if buffers overflow. Traffic management denotes to the set of traffic controls contained by the network that control traffic flows for the principle of maintaining the usability of the network during conditions of congestion. Congestion control is the keystone of packet switching networks and it should prevent the congestion collapse, and to provide the fairness of competing flows and to optimize the transport performance indexes. In order to progress fairness in networks of high speed, Core-Stateless Fair Queuing establish a system of open-loop control at the network layer, which set in the label of the rate of flow arrival onto the packet header at edge routers moreover  plunges the packet at core routers on the basis of rate label if congestion occurs.  To work out the oscillation trouble, the Stable Token-Limited Congestion Control was commenced and there is approximately no packet lost at the congested link

Cellular, Wide-Area, and Non-Terrestrial IoT: A Survey on 5G Advances and the Road Towards 6G

The next wave of wireless technologies is proliferating in connecting things among themselves as well as to humans. In the era of the Internet of things (IoT), billions of sensors, machines, vehicles, drones, and robots will be connected, making the world around us smarter. The IoT will encompass devices that must wirelessly communicate a diverse set of data gathered from the environment for myriad new applications. The ultimate goal is to extract insights from this data and develop solutions that improve quality of life and generate new revenue. Providing large-scale, long-lasting, reliable, and near real-time connectivity is the major challenge in enabling a smart connected world. This paper provides a comprehensive survey on existing and emerging communication solutions for serving IoT applications in the context of cellular, wide-area, as well as non-terrestrial networks. Specifically, wireless technology enhancements for providing IoT access in fifth-generation (5G) and beyond cellular networks, and communication networks over the unlicensed spectrum are presented. Aligned with the main key performance indicators of 5G and beyond 5G networks, we investigate solutions and standards that enable energy efficiency, reliability, low latency, and scalability (connection density) of current and future IoT networks. The solutions include grant-free access and channel coding for short-packet communications, non-orthogonal multiple access, and on-device intelligence. Further, a vision of new paradigm shifts in communication networks in the 2030s is provided, and the integration of the associated new technologies like artificial intelligence, non-terrestrial networks, and new spectra is elaborated. Finally, future research directions toward beyond 5G IoT networks are pointed out.Comment: Submitted for review to IEEE CS&

5g new radio performance assessment

Abstract. Each decade, a new generation of wireless cellular technology presents a step-change in what cellular wireless systems can do compared to the previous generation. It is the beginning of new wireless technology in mobile phone networks called 5th Generation Mobile Phone Network (5G), a robust technology from its predecessors. 5G New Radio (5G NR) is the first step in adapting the 5G wireless technology to the existing cellular infrastructure. This thesis analyzes the 5G NR performance as part of the 5G test network (5GTN) deployed at the University of Oulu. The architecture of the 5GTN is a so-called non- standalone (NSA) network where the 4G Long-Term Evolution (4G-LTE) cellular network provides the control plane of the network. The performance of the 5G NR was obtained by measuring a few primary Key Performance Indicators (KPI) and data transmission measurements to observe the mobile network strength. This thesis first described the importance of 5G and its history, the deployment timeline, the basic architecture of adaption and synchronization process with the current mobile network, and future possibilities. After that, the main KPI parameters, deployed software, and the test case environment are described, and the 5GTN architecture is also covered. Later, the test results are presented, and lastly, a brief discussion of the outcome of the test result is provided. Finally, a comparison between the 5G NR BTS cells within the test environment network is provided. Performance measurements have been performed at the Linnanmaa campus of the University of Oulu and the surrounding premises under the 5GTN, the broadest open- access test network of 5G. The test cases were created during the time of field testing. The measurement key performance indicators (KPIs) have been carefully chosen for these test case scenarios, where the recorded result’s output were analyzed and represented clearly through this study. Data throughput tests have been performed parallelly during the field testing within the network to assess the 5G performance in terms of data rate. Along with the KPI parameter and throughput tests, there is a clear indication that 5G NR offers the fastest connection as part of the existing mobile network infrastructure

車両・無人航空機を活用した災害時情報共有のためのDTNプロトコル

電気通信大学202

Design of a Flexible and Modular Test Bed for Studies on Islanded Microgrids

The last two decades in the electric power sector have been increasingly dominated by a rising interest in the integration of distributed energy resources (DERs) into electric power systems, many of them based on renewable energies. A wider-scale deployment of DERs raises questions in the design, planning and operation of electricity grids. In particular, the operational paradigms of distribution grids are about to change significantly. One way proposed for putting small-scale DERs into the heart of an electric power system is through realizing “Microgrids”. The concept of Microgrids proposes methods to allow participation of DERs in main and ancillary services on the level of distribution grids. To foster research and development in the fields of Microgrids and grid-connected power electronic converters, test beds with adequate functionality are required. Around the world, many test beds have been created to allow experimentation and collection of experiences using full-scale, real equipment and fixed network layouts. However, these test beds are expensive, costly and large, and do not offer a high flexibility for reconfiguration. Therefore, this thesis proposes, implements and evaluates a Microgrid test bed using the Hardware-in-the-loop approach to simulate the behavior of different types of generation, energy storage and loads in a Microgrid. Identical power electronic converter modules are used to generate the currents, voltages and powers required to imitate the AC-bus grid connection of such grid participants. Software models govern converter control and plant simulation, allowing for a fast and flexible reconfiguration of the en-tire test bed. This approach heavily cuts down cost, size and weight of test beds and allows a much more flexible and reproducible creation and execution of test scenarios.4 month

Research on Reliable Low-Power Wide-Area Communications Utilizing Multi-RAT LPWAN Technologies for IoT Applications

Předkládaná disertační práce je zaměřena na „Výzkum spolehlivé komunikace pro IoT aplikace v bezdrátových sítích využívajících technologie Multi-RAT LPWAN“. Navzdory značnému pokroku v oblasti vývoje LPWA technologií umožňující masivní komunikace mezi zařízeními (mMTC), nemusí tyto technologie výkonnostně dostačovat pro nově vznikající aplikace internetu věcí. Hlavním cílem této disertační práce je proto nalezení a vyhodnocení limitů současných LPWA technologií. Na základě těchto dat jsou nevrženy nové mechanismy umožňující snazší plánování a vyhodnocování síťového pokrytí. Navržené nástroje jsou vyladěny a validovány s využitím dat získaných z rozsáhlých měřících kampaních provedených v zákaznických LPWA sítích. Tato disertační práce dále obsahuje návrh LPWA zařízení vybavených více komunikačními rozhraními (multi-RAT) které mohou umožnit překonání výkonnostních limitů jednotlivých LPWA technologií. Současná implementace se zaměřuje zejména na snížení spotřeby zařízení s více rádiovými rozhraními, což je jejich největší nevýhodou. K tomuto účelu je využito algoritmů strojového učení, které jsou schopné dynamicky vybírat nejvhodnější rozhraní k přenosu.This doctoral thesis addresses the “Research on Reliable Low-Power Wide-Area Communications Utilizing Multi-RAT LPWAN Technologies for IoT Applications”. Despite the immense progress in massive Machine-Type Communication (mMTC) technology enablers such as Low-Power Wide-Area (LPWA) networks, their performance does not have to satisfy the requirements of novelty Internet of Things (IoT) applications. The main goal of this Ph.D. work is to explore and evaluate the limitations of current LPWA technologies and propose novel mechanisms facilitating coverage planning and assessment. Proposed frameworks are fine-tuned and cross-validated by the extensive measurement campaigns conducted in public LPWA networks. This doctoral thesis further introduces the novelty approach of multi-RAT LPWA devices to overcome the performance limitation of individual LPWA technologies. The current implementation primarily focuses on diminishing the greatest multi-RAT solutions disadvantage, i.e., increased power consumption by employing a machine learning approach to radio interface selection.