scholarly journals Increasing Wireless Adhoc Network Capacity through Simultaneous Transmissions

2015 ◽  
Vol 1 (1) ◽  
pp. 35-54
Author(s):  
Robert Hunjet ◽  
Andrew Coyle
Keyword(s):  
Wireless Networks ◽  
Wireless Network ◽  
Power Efficiency ◽  
Power Transmission ◽  
High Capacity ◽  
Local Maximum ◽  
Network Capacity ◽  
Transmission Power ◽  
High Power Transmission ◽  
Network Power

A great deal of research has been carried out regarding increasing the capacity of wireless networks. The general findings are that increasing the number of nodes in a wireless network decreases individual throughput, simultaneous transmissions cause interference and therefore hinder capacity, and that topology control can increase network power efficiency and reduce the interference within the network. This paper demonstrates that appropriately spaced simultaneous transmissions are beneficial to the capacity of shared spectrum wireless networks and that adding nodes to a wireless network can, in fact, increase its capacity if the nodes are intelligently placed and node transmission powers are appropriately set. In this paper we firstly discuss the inefficiency of high power transmission for networks which allow simultaneous transmissions. It is then demonstrated that if multiple transmitters are utilised simultaneously with uniform transmission power, the network capacity is a local maximum if the required spacing conditions between the receivers are met. In the presence of background noise one can determine that this configuration represents the maximum network capacity achievable. The required separation is defined for the general case and shown to decrease as the number of simultaneous transmissions increases. This result is verified through simulations which demonstrate the construction of high capacity networks. Simulations are also presented which show how existing networks can be augmented with additional nodes and a reduction of transmission power, to exhibit higher uniform average network capacities.

scholarly journals On Simultaneously Increasing MANET Survivability, Capacity, Power Efficiency and Security

2016 ◽  
Vol 2 (1) ◽  
pp. 85-107
Author(s):  
Robert Hunjet
Keyword(s):  
Wireless Networks ◽  
Ad Hoc Networks ◽  
Power Control ◽  
Power Efficiency ◽  
Ad Hoc ◽  
Network Capacity ◽  
Cross Entropy ◽  
Transmission Power ◽  
Optimal Distance ◽  
Hoc Networks

Increasing the capacity, survivability and power efficiency of wireless networks are often seen as competing goals. This paper shows that it is possible to pursue these goals simultaneously in ad hoc networks through the use of a multi-objective cross entropy optimisation operating on the placement of additional nodes and transmission power control. Encouraging results were obtained through simulation, with substantial capacity gains and associated transmission power savings achieved, whilst offering survivability through bi-connected topologies. This paper also discusses how the increase in power efficiency improves the security of the network by reducing the range at which messages within the network can be detected and decoded by eavesdropping nodes. A derivation of the optimal distance required between senders and receivers in the presence of noise is described, and the effects of relaying on overall network capacity and node throughput are discussed.

Experimental Research on the Influence of Transmission Parameters on the Transmission Performance of Magnetic Resonance Wireless Power Transmission Systems

2014 ◽  
Vol 551 ◽  
pp. 393-398
Author(s):  
Chang Sheng Li ◽  
He Zhang ◽  
Xiao Hua Jiang
Keyword(s):  
Magnetic Resonance ◽  
Power Efficiency ◽  
High Efficiency ◽  
Power Transmission ◽  
Transmission Power ◽  
Wireless Power ◽  
Transmission Performance ◽  
Wireless Power Transmission ◽  
Transmission Systems ◽  
Transmission Parameters

Magnetic resonance wireless power transmission uses resonance strong coupling between the transmission and receiving terminals to realize a non-contact efficient supply of energy over large distance. The transmission power, efficiency and distance are confirmed by comprehensive function of the transmission parameters. By taking experimental means, the influence laws of loop transmission parameters, such as separation between coils, coil size, etc., on the transmission performance are studied in this paper. The experimental results show that the power high-efficiency and high-quality transmission does not depend on the large coil loop coupling coefficient and transmission power and efficiency may increase firstly and then decline as the separation between coils increases. The transmission performance can be optimized by increasing the coils diameter or wire diameter, and moreover, transmission systems with a high resonance frequency can produce high power and efficiency transmission over short distances.

An Experimental Study

2014 ◽  
Vol 6 (3) ◽  
pp. 35-53
Author(s):  
Edith N. Ekwem ◽  
Kashif Nisar
Keyword(s):  
Wireless Networks ◽  
Wireless Network ◽  
Performance Metrics ◽  
Local Area Network ◽  
Telecommunication Network ◽  
Local Area ◽  
Network Capacity ◽  
Area Network ◽  
Performance Study ◽  
Network Simulators

A network whose interconnections between nodes are implemented without using wires is referred to as wireless network and is usually related to a telecommunication network. As related to wired local area network, wireless channels are error-prone. Performance study and optimization of Wireless Local Area Network (WLAN) becomes more essential as its gaining popularity. For performance modelling and evaluation of wireless networks, computer simulation has become one of most widespread tools. While numerous network simulators exist for building a variety of network models, selecting a good network simulator tool is vital in modelling and performance study of wireless networks. Optimized Network Engineering Tools (OPNET) Modeller available to academic institutions at no cost is becoming one of the most widespread network simulators. In this study, the authors used OPNET Modeller 14.5 simulator tool to develop and validate a model for campus based WLAN. The results are expected to display that OPNET Modeller offers credible simulation outcomes close to a genuine system. The effect of network parameters such as the processing time on the performance metrics such as delay and throughput of the various scenarios in the entire network was investigated. The analysis of the results from the simulations carried out can assist the management of computer centre that manages the network in identifying the bottleneck node on the network and for future network capacity building. However, this wireless network involves too many numbers of users which OPNET is not capable to simulate; the authors limited the network to only users in the computer building.

Demand of Wireless Network and Security in Current Research

2015 ◽  
Vol 14 (6) ◽  
pp. 5809-5813
Author(s):  
Abhishek Prabhakar ◽  
Amod Tiwari ◽  
Vinay Kumar Pathak
Keyword(s):  
Wireless Networks ◽  
Quality Of Service ◽  
Wireless Network ◽  
Network Performance ◽  
Wireless Security ◽  
Human Intervention ◽  
Unauthorized Access ◽  
Quality Of Service Parameters ◽  
Wireless Infrastructure

Wireless security is the prevention of unauthorized access to computers using wireless networks .The trends in wireless networks over the last few years is same as growth of internet. Wireless networks have reduced the human intervention for accessing data at various sites .It is achieved by replacing wired infrastructure with wireless infrastructure. Some of the key challenges in wireless networks are Signal weakening, movement, increase data rate, minimizing size and cost, security of user and QoS (Quality of service) parameters... The goal of this paper is to minimize challenges that are in way of our understanding of wireless network and wireless network performance.

scholarly journals Simulation of 2-Coil and 4-Coil Magnetic Resonance Wearable WPT Systems

Proceedings ◽  
2021 ◽  
Vol 68 (1) ◽  
pp. 13
Author(s):  
Yixuan Sun ◽  
Stephen Beeby
Keyword(s):  
Power Efficiency ◽  
Power Transmission ◽  
Rotation Angle ◽  
Wireless Power ◽  
Peak Efficiency ◽  
Frequency Splitting ◽  
At Resonance ◽  
Higher Power ◽  
The Impact ◽  
Proper Frequency

This paper presents the COMSOL simulations of magnetically coupled resonant wireless power transfer (WPT), using simplified coil models for embroidered planar two-coil and four-coil systems. The power transmission of both systems is studied and compared by varying the separation, rotation angle and misalignment distance at resonance (5 MHz). The frequency splitting occurs at short separations from both the two-coil and four-coil systems, resulting in lower power transmission. Therefore, the systems are driven from 4 MHz to 6 MHz to analyze the impact of frequency splitting at close separations. The results show that both systems had a peak efficiency over 90% after tuning to the proper frequency to overcome the frequency splitting phenomenon at close separations below 10 cm. The four-coil design achieved higher power efficiency at separations over 10 cm. The power efficiency of both systems decreased linearly when the axial misalignment was over 4 cm or the misalignment angle between receiver and transmitter was over 45 degrees.

scholarly journals Planning capacity for 5G and beyond wireless networks by discrete fireworks algorithm with ensemble of local search methods

2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
Hafiz Munsub Ali ◽  
Jiangchuan Liu ◽  
Waleed Ejaz
Keyword(s):  
Wireless Networks ◽  
Local Search ◽  
Wireless Network ◽  
Statistical Tests ◽  
Mathematical Framework ◽  
Integer Programming Problem ◽  
Search Methods ◽  
Fireworks Algorithm ◽  
Local Search Methods ◽  
Planning Capacity

Abstract In densely populated urban centers, planning optimized capacity for the fifth-generation (5G) and beyond wireless networks is a challenging task. In this paper, we propose a mathematical framework for the planning capacity of a 5G and beyond wireless networks. We considered a single-hop wireless network consists of base stations (BSs), relay stations (RSs), and user equipment (UEs). Wireless network planning (WNP) should decide the placement of BSs and RSs to the candidate sites and decide the possible connections among them and their further connections to UEs. The objective of the planning is to minimize the hardware and operational cost while planning capacity of a 5G and beyond wireless networks. The formulated WNP is an integer programming problem. Finding an optimal solution by using exhaustive search is not practical due to the demand for high computing resources. As a practical approach, a new population-based meta-heuristic algorithm is proposed to find a high-quality solution. The proposed discrete fireworks algorithm (DFWA) uses an ensemble of local search methods: insert, swap, and interchange. The performance of the proposed DFWA is compared against the low-complexity biogeography-based optimization (LC-BBO), the discrete artificial bee colony (DABC), and the genetic algorithm (GA). Simulation results and statistical tests demonstrate that the proposed algorithm can comparatively find good-quality solutions with moderate computing resources.

scholarly journals Global experience of HVDC composite insulators in outdoor and indoor environment

2020 ◽  
Vol 59 (1) ◽  
pp. 606-618
Author(s):  
Mohammad Akbar ◽  
Basharat Mehmood
Keyword(s):  
High Voltage ◽  
Direct Current ◽  
Transmission Lines ◽  
Power Transmission ◽  
Green Energy ◽  
Attractive Alternative ◽  
Hvdc Transmission ◽  
Ceramic Insulators ◽  
High Power Transmission ◽  
Aging Performance

AbstractHigh-voltage direct current (HVDC) transmission is known as green-energy transfer technology and has recently become an attractive alternative of high-voltage alternating current (HVAC) due to its high-power transmission capability and lower power loss. Use of composite insulators on direct current (DC) transmission lines experienced rapid growth in recent years due to their high hydrophobicity and better performance in contaminated environment than conventional ceramic insulators. During their service operation on DC lines, insulators are prone to more accumulation of contaminants due to unidirectional electric field. The contaminants under wet conditions allow leakage current to flow on the insulator surface. Being organic in nature, polymeric insulators have a tendency to age under the combined effects of electrical and environmental stresses. To fully understand the long-term aging performance of DC composite insulators, a detailed survey was considered necessary. Towards that end, this paper critically summarizes worldwide experience of aging performance of composite insulators in the field as well as in laboratory conditions.

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