Effects of directional antennas at the base station on the Doppler spectrum

1997 ◽  
Vol 1 (2) ◽  
pp. 40-42 ◽  
Author(s):  
P. Petrus ◽  
J.H. Reed ◽  
T.S. Rappaport
Keyword(s):  
Directional Antennas ◽  
Base Station ◽  
Doppler Spectrum

scholarly journals Improved Algorithms for Data-Gathering Time in Sensor Networks II: Ring, Tree, and Grid Topologies

2009 ◽  
Vol 5 (5) ◽  
pp. 463-479 ◽  
Author(s):  
Yoram Revah ◽  
Michael Segal
Keyword(s):  
Data Gathering ◽  
Directional Antennas ◽  
Base Station ◽  
Sensor Nodes ◽  
Delivery Time ◽  
Packet Delivery ◽  
Central Node ◽  
Hazard Detection ◽  
Wide Range ◽  
Efficient Data

We address the problem of gathering information in sensor webs consisting of sensors nodes, wherein a round of communication sensor nodes have messages to be sent to a distant central node (called the base station) over the shortest path. There is a wide range of data gathering applications like target and hazard detection, environmental monitoring, battlefield surveillance, etc. Consequently, efficient data collection solutions are needed to improve the performance of the network. In this article, we take into account the fact that interference can occur at the reception of a message at the receiver sensor. In order to save redundant retransmissions and energy, we assume a known distribution of sources (each node wants to transmit at most one packet) and one common destination. We provide a number of scheduling algorithms jointly minimizing both the completion time and the average packet delivery time. We define our network model using directional antennas and consider Ring, Tree, and Grid Network (and its generality) topologies. All our algorithms run in low-polynomial time.

scholarly journals On the Interpretation of the Doppler Spectra of Ionospherically Propagated Ground Backscatter Echoes

1975 ◽  
Vol 28 (5) ◽  
pp. 575
Author(s):  
JA Bennett
Keyword(s):  
Simple Model ◽  
Acoustic Wave ◽  
Group Velocity ◽  
Realistic Model ◽  
Directional Antennas ◽  
Doppler Spectrum ◽  
Sea Waves ◽  
Dispersive Waves ◽  
Time Changes ◽  
The Way

The mechanism giVing rise to the backscatter Doppler spectrum is discussed by means of a simple model. Attention is focused on the effect of movement of the region contributing to the echo which arises from time changes in the group velocity within the ionosphere. It is shown that the influence of these changes on the spectrum can be separated into two parts: (1) A change in the maximum possible width of the spectrum as a result of the change of the time for which an indiVidual scatterer is contributing to the echo; this effect is independent of the scatterer distribution. (2) A possible narrowing of the spectrum as a result of the way in which the signals from individual scatterers combine; this effect depends upon scatterer distribution. Scatter from a fixed'scattering surface and from dispersive waves (e.g. sea waves) is considered. A tentative extrapolation of the results to a more realistic model suggests that neither effect is likely to be significant in practical highfrequency radio experiments (except at short ranges with highly directional antennas), although they may be significant in acoustic wave simulations of the radio case.

scholarly journals Selective Mobile Communication within a Coverage Area Bounded by Radiating Cables

2015 ◽  
Vol 2015 ◽  
pp. 1-9
Author(s):  
Hatim Behairy ◽  
Waleed Alrobian ◽  
Adnan Alghammas ◽  
Amr Alasaad ◽  
Brian Suter ◽  
...  
Keyword(s):  
Mobile Phone ◽  
Mobile Devices ◽  
Mobile Phones ◽  
Mobile Communication ◽  
Mobile Services ◽  
Directional Antennas ◽  
Base Station ◽  
Coverage Area ◽  
Precise Control ◽  
Novel Technique

It is often desirable to control mobile phone services in areas where complete silence is either expected or mandatory, including schools, places of worship, hospitals, and prisons. In contrast to conventional techniques, such as jammers or Faraday cages, we present a novel technique to selectively control mobile phone services within a desired area. Our solution enables the area’s keeper to allow mobile phones on a whitelist to freely use mobile services without disruption while denying services to all other mobile phones that are within the boundaries of the desired area to be controlled. Our solution uses a base station controller to identify all mobile devices located within the area to be controlled, while an antenna is placed inside the area to attract all mobile devices in the area to connect to the base station controller. In previous work, we proposed a system that uses directional antennas for the attraction technique. In this work, we show that replacement of the directional antennas with a leaky feeder antenna enables more accurate control of mobile phone services in and around the area to be controlled. Simulations and experiments of the leaky feeder technique confirm its precise control of mobile phone services within the desired areas.

scholarly journals Design Radio Network Links to Provide Internet for Pupulation of San Andres de Llamellin-Ancash

2022 ◽  
Vol 12 (1) ◽  
pp. 51-62
Author(s):  
Andres Valencia Acuña ◽  
◽  
Brian Meneses Claudio ◽  
Alexi Delgado
Keyword(s):  
Average Distance ◽  
Directional Antennas ◽  
Base Station ◽  
Radio Link ◽  
Radio Network ◽  
Complete Coverage ◽  
Coverage Area ◽  
Virtual Classes ◽  
San Andres

In recent years being able to have access to the internet has become a tool not only to be able to communicate in the distance but it is a great tool to be able to feed knowledge, it is because of them that children have a great educational utility and after this pandemic in Peru it was necessary to close schools, to be able to give remote classes or virtual classes. To solve the problem, we propose to be able to design a network of radio links whereby means of a base station of emission and reception, with an antenna of sectorial type and directional antennas to be able to realize a Point – Multipoint link which will be able to manage the quality of signal by means of a routing with functions of control of speeds for each connection of each home. It was the result that the connections of the radio link at an average distance from the coverage that the network had the signal was better and that the connections that were very far or close to the coverage area had complications, but despite this the connections were sufficient to be able to maintain the virtual classes that is what was planned. It is recommended that for a better connection and complete coverage it would be to reinforce the broadcast base with more sectoral antennas in the network. Keywords- Radio link, Point - Multipoint, Router, Download speed, Upload speed.

A Survey on Hierarchical Cluster Based Secure Routing Protocols and Key Management Schemes in Wireless Sensor Networks

2018 ◽  
pp. 18-26
Author(s):  
Yugashree Bhadane ◽  
Pooja Kadam
Keyword(s):  
Routing Protocol ◽  
Routing Protocols ◽  
Key Management ◽  
Energy Efficient ◽  
Base Station ◽  
Secure Routing ◽  
Sensor Nodes ◽  
Wireless Sensor ◽  
Management Schemes ◽  
Cluster Based Routing

Now days, wireless technology is one of the center of attention for users and researchers. Wireless network is a network having large number of sensor nodes and hence called as “Wireless Sensor Network (WSN)”. WSN monitors and senses the environment of targeted area. The sensor nodes in WSN transmit data to the base station depending on the application. These sensor nodes communicate with each other and routing is selected on the basis of routing protocols which are application specific. Based on network structure, routing protocols in WSN can be divided into two categories: flat routing, hierarchical or cluster based routing, location based routing. Out of these, hierarchical or cluster based routing is becoming an active branch of routing technology in WSN. To allow base station to receive unaltered or original data, routing protocol should be energy-efficient and secure. To fulfill this, Hierarchical or Cluster base routing protocol for WSN is the most energy-efficient among other routing protocols. Hence, in this paper, we present a survey on different hierarchical clustered routing techniques for WSN. We also present the key management schemes to provide security in WSN. Further we study and compare secure hierarchical routing protocols based on various criteria.

Fair Deployment of an Unmanned Aerial Vehicle Base Station for Maximal Coverage

2019 ◽  
Vol E102.B (10) ◽  
pp. 2014-2020
Author(s):  
Yancheng CHEN ◽  
Ning LI ◽  
Xijian ZHONG ◽  
Yan GUO
Keyword(s):  
Unmanned Aerial Vehicle ◽  
Base Station ◽  
Aerial Vehicle
Sign in / Sign up

Export Citation Format

Share Document