Sectoring Method for Improving Various QoS Parameters of Wireless Sensor Networks to Improve Lifespan of the Network

The wireless sensor network is set of distributed nodes, which are randomly deployed in sensor field to capture various parameters and send it to receiver station for further analysis and prediction. There are two types of protocols essential for communication. One is MAC protocol and another is routing protocol. Routing protocols are used for finding shortest path between sources to destination. MAC protocols are used for reliable data delivery from source to destination. The design of a reliable wireless sensor network (WSN) must handle the failure of single or many network components, still, because of the deployment of mechanisms to tolerate faults at various levels. the most objective of this paper is to review different existing algorithms proposed by different researchers and merge their work for further study. This paper studies different prototypes and proposed algorithms, and also the objectives of the papers. Also, the paper elaborates on the proposed algorithm within the particular paper together with their objectives. Proposed algorithm is very useful for to reduce heavy congestion over the networks and achieve various parameters of sensor networks

Energy and Spectral Efficiency Balancing Algorithm for Energy Saving in LTE Downlinks

In wireless network communication environments, Spectral Efficiency (SE) and Energy Efficiency (EE) are among the major indicators used for evaluating network performance. However, given the high demand for data rate services and the exponential growth of energy consumption, SE and EE continue to elicit increasing attention in academia and industries. Consequently, a study of the trade-off between these metrics is imperative. In contrast with existing works, this study proposes an efficient SE and EE trade-off algorithm for saving energy in downlink Long Term Evolution (LTE) networks to concurrently optimize SE and EE while considering battery life at the Base Station (BS). The scheme is formulated as a Multi-objective Optimization Problem (MOP) and its Pareto optimal solution is examined. In contrast with other algorithms that prolong battery life by considering the idle state of a BS, thereby increasing average delay and energy consumption, the proposed algorithm prolongs battery life by adjusting the initial and final states of a BS to minimize the average delay and the energy consumption. Similarly, the use of an omni-directional antenna to spread radio signals to the user equipment in all directions causes high interference and low spatial reuse. We propose using a directional antenna instead of an omni-directional antenna by transmitting signals in one direction which results in no or low interference and high spatial reuse. The proposed scheme has been extensively evaluated through simulation, where simulation results prove that the proposed scheme is efficiently able to decrease the average response delay, improve SE, and minimize energy consumption.Comment: 19 page

Real-time energy optimization of irrigation scheduling by parallel multi-objective genetic algorithms

[EN] The present work is motivated by the need to reduce the energy costs arising from the pressure demands of drip and sprinkling irrigation, compounded by the increase in the energy price in recent years. Researchers have demonstrated that proper operation of the irrigation network reduces associated pumping costs. The main challenge was to obtain the optimal operation parameters on near real-time due to the fact that the high complexity of the optimization problem requires a great computational effort. The classic approach to the problem imposes a strict fulfilment of minimum pressures as a restriction. This study, however, presents a new methodology for the reordering of irrigation scheduling, incorporating the constraint of daily volume requests for each hydrant. The methodology is capable of minimizing the cost of energy while maximizing pressures at the critical hydrants. Cost reductions of about 6¿7% were reached for scenarios without pressure deficit for the case study. Greater computational efficiency was achieved by posing the problem from a multi-objective approach, on the one hand, and by establishing the parallel evaluation of the objective function, on the other. The speed-up obtained by combining a reduction in the number of function evaluations thanks to the faster convergence of the multi-objective approach and the reduction of the computational time due to the parallelization of the algorithm achieved results about 10 times faster. This improvement allowed the tool to be implemented for the daily optimization of irrigation requests.This work has been supported by the VALi+D R&D Program of the Generalitat Valenciana (Spain).Alonso-Campos, J.; Jiménez Bello, MA.; Martínez Alzamora, F. (2020). Real-time energy optimization of irrigation scheduling by parallel multi-objective genetic algorithms. Agricultural Water Management. 227:1-8. https://doi.org/10.1016/j.agwat.2019.105857S1822

Energy Efficient Relay-Assisted Cellular Network Model using Base Station Switching

Cellular network planning strategies have tended to focus on peak traffic scenarios rather than energy efficiency. By exploiting the dynamic nature of traffic load profiles, the prospect for greener communications in cellular access networks is evolving. For example, powering down base stations (BS) and applying cell zooming can significantly reduce energy consumption, with the overriding design priority still being to uphold a minimum quality of service (QoS). Switching off cells completely can lead to both coverage holes and performance degradation in terms of increased outage probability, greater transmit power dissipation in the up and downlinks, and complex interference management, even at low traffic loads. In this paper, a cellular network model is presented where certain BS rather than being turned off, are switched to low-powered relay stations (RS) during zero-to-medium traffic periods. Neighbouring BS still retain all the baseband signal processing and transmit signals to corresponding RS via backhaul connections, under the assumption that the RS covers the whole cell. Experimental results demonstrate the efficacy of this new BS-RS Switching technique from both an energy saving and QoS perspective, in the up and downlinks

Planning for Small Cells in a Cellular Network

In this thesis, we analyze the effect of deploying small cells on the performance of a network comprising several macro cells. We identify potential locations for low-power base-stations based on the coverage patterns of the macro cells and propose three schemes for placing the small cells. We show that by judiciously installing just two small cells for every macro base-station at these locations and allocating separate resources to all the small cells on a global level, we can increase the performance of the network significantly (~ 45%). An added benefit of our schemes is that we can switch o the macro base-stations at night (when the number of active users is low) and significantly reduce their operation cost.4 month

A survey of self organisation in future cellular networks

This article surveys the literature over the period of the last decade on the emerging field of self organisation as applied to wireless cellular communication networks. Self organisation has been extensively studied and applied in adhoc networks, wireless sensor networks and autonomic computer networks; however in the context of wireless cellular networks, this is the first attempt to put in perspective the various efforts in form of a tutorial/survey. We provide a comprehensive survey of the existing literature, projects and standards in self organising cellular networks. Additionally, we also aim to present a clear understanding of this active research area, identifying a clear taxonomy and guidelines for design of self organising mechanisms. We compare strength and weakness of existing solutions and highlight the key research areas for further development. This paper serves as a guide and a starting point for anyone willing to delve into research on self organisation in wireless cellular communication networks

An updated annotated bibliography on arc routing problems

The number of arc routing publications has increased significantly in the last decade. Such an increase justifies a second annotated bibliography, a sequel to Corberán and Prins (Networks 56 (2010), 50–69), discussing arc routing studies from 2010 onwards. These studies are grouped into three main sections: single vehicle problems, multiple vehicle problems and applications. Each main section catalogs problems according to their specifics. Section 2 is therefore composed of four subsections, namely: the Chinese Postman Problem, the Rural Postman Problem, the General Routing Problem (GRP) and Arc Routing Problems (ARPs) with profits. Section 3, devoted to the multiple vehicle case, begins with three subsections on the Capacitated Arc Routing Problem (CARP) and then delves into several variants of multiple ARPs, ending with GRPs and problems with profits. Section 4 is devoted to applications, including distribution and collection routes, outdoor activities, post-disaster operations, road cleaning and marking. As new applications emerge and existing applications continue to be used and adapted, the future of arc routing research looks promising.info:eu-repo/semantics/publishedVersio

A PC-oriented interactive tool for finding efficient solutions to emergency planning problems

Includes bibliographical references (p. 43-44).by Oli B.C. Madsen and Richard C. Larson

Delimitation of service areas in reverse logistics networks with multiple depots

WOS:000290258800003 (Nº de Acesso Web of Science)“Prémio Científico ISCTE-IUL 2012”This paper describes a heuristic approach for the definition of service (or influence) areas of multiple depots in a reverse logistics network. This work is based on a case study: the recyclable waste collection system with 5 depots that covers seven municipalities in the Alentejo region, southern Portugal. The system optimization considers two objectives, related with economic and organizational issues: minimizing the variable costs (function of the travelled distances by the collection vehicles), and the pursuit of equity, aiming at minimizing the workload differences among depots. The goal of balancing workloads poses a problem not usually treated in the existing literature. This fact required the development of a new approach with innovative elements adjusted to the existing circumstances