941 research outputs found
Energy efficient routing towards a mobile sink using virtual coordinates in a wireless sensor network
The existence of a coordinate system can often improve the routing in a wireless sensor network. While most coordinate systems correspond to the geometrical or geographical coordinates, in recent years researchers had proposed the use of virtual coordinates. Virtual coordinates depend only on the topology of the network as defined by the connectivity of the nodes, without requiring geographical information. The work in this thesis extends the use of virtual coordinates to scenarios where the wireless sensor network has a mobile sink. One reason to use a mobile sink is to distribute the energy consumption more evenly among the sensor nodes and thus extend the life-time of the network. We developed two algorithms, MS-DVCR and CU-DVCR which perform routing towards a mobile sink using virtual coordinates. In contrast to the baseline virtual coordinate routing MS-DVCR limits routing updates triggered by the sink movement to a local area around the sink. In contrast, CU-DVCR limits the route updates to a circular area on the boundary of the local area. We describe the design justification and the implementation of these algorithms. Using a set of experimental studies, we show that MS-DVCR and CU-DVCR achieve a lower energy consumption compared to the baseline virtual coordinate routing without any noticeable impact on routing performance. In addition, CU-DVCR provides a lower energy consumption than MS-DVCR for the case of a fast moving sink
Building the sensory mesh network of IIoT based on Bluetooth 4.2 technology
У даній статті розглянуто особливості технології сенсорних mesh-мереж на базі технології Bluetooth Low Energy (BLE) для моніторингу об’єктів управління. Описана технологія BLE. Проаналізовано можливість використання Bluetooth як бази для mesh-мережі. Розглянуто варіанти ініціалізації вузлів мережі, а також, адресацію і передачу даних між ними. Розглянуто способи реалізації mesh-мережі з використанням Bluetooth. Наведено реалізацію простої мережі на прикладі моніторингу температури і вологості повітря в лікарні.This paper considered features of technology of sensory networks based on the BLE format for monitoring objects of management. BLE format is described. The possibility of using Bluetooth as the basis of the mesh topology network is analyzed. Options for initializing network nodes as well as addressing and transmitting data between them are considered. The ways of creating of Bluetooth mesh-network are considered. The main goal of this paper is to show, that there is technology, that can be used for creating low energy and secure mesh networks without complicated realization on existing routing protocols. There are three main solution directions of creating bluetooth mesh networks communication: standart, academic and proprietary. Academic is the most ordinary and simple. So if network require dynamic reorganization of nodes, for example cars on roads - flooding based or dynamic routing will be the most effective, and if all nodes won`t be able to change its position like sensors in industrial manufacture - static routing solution will be exactly workable. The implementation of a simple network is illustrated by the example of monitoring the temperature and humidity in the hospital. As a result, we have easy implementational mesh topology network, built with the use of Bluetooth technology as the base. That also have Low Energy and high secure connection features along low price. Although there are no routing protocols created exactly for BLE - existing solutions can be integrated in implementations of similar systems. Also, description of the technology can give impuls to create an adapted communication protocol for routing between the nodes of the Blutooth mesh network
The Four Principles of Geographic Routing
Geographic routing consists in using the position information of nodes to
assist in the routing process, and has been a widely studied subject in sensor
networks. One of the outstanding challenges facing geographic routing has been
its applicability. Authors either make some broad assumptions on an idealized
version of wireless networks which are often unverifiable, or they use costly
methods to planarize the communication graph.
The overarching questions that drive us are the following. When, and how
should we use geographic routing? Is there a criterion to tell whether a
communication network is fit for geographic routing? When exactly does
geographic routing make sense?
In this paper we formulate the four principles that define geographic routing
and explore their topological consequences. Given a localized communication
network, we then define and compute its geographic eccentricity, which measures
its fitness for geographic routing. Finally we propose a distributed algorithm
that either enables geographic routing on the network or proves that its
geographic eccentricity is too high.Comment: This manuscript on geographic routing incoporates team feedback and
expanded experiment
Self-Evolving Integrated Vertical Heterogeneous Networks
6G and beyond networks tend towards fully intelligent and adaptive design in
order to provide better operational agility in maintaining universal wireless
access and supporting a wide range of services and use cases while dealing with
network complexity efficiently. Such enhanced network agility will require
developing a self-evolving capability in designing both the network
architecture and resource management to intelligently utilize resources, reduce
operational costs, and achieve the coveted quality of service (QoS). To enable
this capability, the necessity of considering an integrated vertical
heterogeneous network (VHetNet) architecture appears to be inevitable due to
its high inherent agility. Moreover, employing an intelligent framework is
another crucial requirement for self-evolving networks to deal with real-time
network optimization problems. Hence, in this work, to provide a better insight
on network architecture design in support of self-evolving networks, we
highlight the merits of integrated VHetNet architecture while proposing an
intelligent framework for self-evolving integrated vertical heterogeneous
networks (SEI-VHetNets). The impact of the challenges associated with
SEI-VHetNet architecture, on network management is also studied considering a
generalized network model. Furthermore, the current literature on network
management of integrated VHetNets along with the recent advancements in
artificial intelligence (AI)/machine learning (ML) solutions are discussed.
Accordingly, the core challenges of integrating AI/ML in SEI-VHetNets are
identified. Finally, the potential future research directions for advancing the
autonomous and self-evolving capabilities of SEI-VHetNets are discussed.Comment: 25 pages, 5 figures, 2 table
Encounter gossip: a high coverage broadcast protocol for MANET
PhD ThesisMobile Ad-hoc Networks (MANETs) allow deployment of mobile wireless devices or nodes in a range of environments without any fixed infrastructure and hence at a minimal setup cost. Broadcast support that assures a high coverage (i.e., a large fraction of nodes receiving a broadcast) is essential
for hosting user applications, and is also non-trivial to achieve due to the nature of devices and mobility. We propose Encounter Gossip, a novel broadcast protocol, which holds minimal state and is unaware of network topology. Coverage obtained can be made arbitrarily close to 1 at a moderate
cost of extra message tra c, even in partition-prone networks. Under certain simplifying assumptions, it is shown that a high coverage is achieved by making a total of O(n ln n) broadcasts, where n is
the number of nodes, and the time to propagate a message is O(ln n). The e ect of various network parameters on the protocol performance is examined. We then propose modifications to minimise the number of redundant transmissions without compromising the achieved coverage. Two approaches
are pursued: timer based and history based. The e ectiveness of each of these approaches is assessed through an extensive set of simulation experiments in the context of two mobility models. Specifically, we introduce a new heuristic alpha policy which achieves significant reduction in redundancy with
negligible reduction in coverage. A generalisation to multiple broadcasts proceeding in parallel is proposed and the protocol is refined to reduce problems that can occur due to the effects of high mobility when transmitting a large number of messages. Finally, we implement and validate
Encounter Gossip in the context of a real-life mobile ad-hoc network. All these investigations suggest that the protocol, together with the proposed modifications and re nements, is suited to MANETs
of varying degrees of node densities and speeds
CHANNEL MODELING FOR FIFTH GENERATION CELLULAR NETWORKS AND WIRELESS SENSOR NETWORKS
In view of exponential growth in data traffic demand, the wireless communications industry has aimed to increase the capacity of existing networks by 1000 times over the next 20 years. A combination of extreme cell densification, more bandwidth, and higher spectral efficiency is needed to support the data traffic requirements for fifth generation (5G) cellular communications. In this research, the potential improvements achieved by using three major 5G enabling technologies (i.e., small cells, millimeter-wave spectrum, and massive MIMO) in rural and urban environments are investigated. This work develops SPM and KA-based ray models to investigate the impact of geometrical parameters on terrain-based multiuser MIMO channel characteristic. Moreover, a new directional 3D channel model is developed for urban millimeter-wave (mmW) small cells. Path-loss, spatial correlation, coverage distance, and coherence length are studied in urban areas. Exploiting physical optics (PO) and geometric optics (GO) solutions, closed form expressions are derived for spatial correlation. Achievable spatial diversity is evaluated using horizontal and vertical linear arrays as well as planar 2D arrays. In another study, a versatile near-ground field prediction model is proposed to facilitate accurate wireless sensor network (WSN) simulations. Monte Carlo simulations are used to investigate the effects of antenna height, frequency of operation, polarization, and terrain dielectric and roughness properties on WSNs performance
Multi-User Ultra-Massive MIMO for very high frequency bands (mmWave and THz): a resource allocation problem
A dynamic subarray allocation for multi-user massive MIMO systems working in very high frequency bands (mmWave and THz) is proposed as a promising technique to unleash the capacity limits in future cellular networks capable of supporting high consuming bandwidth applications
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