Investigating the overestimation of base station exposure in urban environments due to assumption of free space propagation

2017 ◽  
Author(s):  
Thomas Kopacz ◽  
Sascha Schiesl ◽  
Dirk Heberling
Keyword(s):  
Free Space ◽  
Base Station ◽  
Urban Environments

Hybrid Analog/Digital Modulations Using Polarization Multiplexing OCDMA Scheme in Free Space Optics

2015 ◽  
Vol 764-765 ◽  
pp. 511-514
Author(s):  
Chih Ta Yen ◽  
Chia Yu Liu
Keyword(s):  
Free Space ◽  
Orthogonal Frequency Division Multiplexing ◽  
Multiple Access ◽  
High Speed ◽  
Base Station ◽  
Free Space Optics ◽  
Detection Scheme ◽  
Space Optics ◽  
Polarization Multiplexing ◽  
Code Division Multiple

With the development of the Internet, how to provide a high-speed and high-security comprehensive network has become urgent issue. In this project, we propose hybrid analog/digital transmissions format scheme which integrated optical code-division multiple-access (OCDMA) and polarization multiplexing technique in free space optics (FSO) transmission. Orthogonal frequency division multiplexing (OFDM) transmits as the analog format and (on-off keying) OOK transmits as digital format in the study, respectively. In the proposed hybrid OCDMA system, it has high-speed transmission, signal security and low cost...etc. we adopt quasi-orthogonal Walsh-Hadamard codes (WHC) that with fixed cross correlation value as the codeword for each base station. With the property, the multiple access interference (MAI) can be efficiently eliminated by using the balanced detection scheme at the receive end. The constellation and eye diagrams show that both OFDM signal as analog signal and OOK modulation as digital signal in the proposed hybrid OCDMA system perform good performance in FSO transmission.

scholarly journals Propagation models for high sites in urban areas

2006 ◽  
Vol 4 ◽  
pp. 345-349 ◽  
Author(s):  
A. Hecker ◽  
M. Neuland ◽  
T. Kuerner
Keyword(s):  
Urban Areas ◽  
Mobile Station ◽  
Base Station ◽  
Urban Environments ◽  
Angle Of Incidence ◽  
Propagation Models ◽  
Validity Range ◽  
A Site

Abstract. Analyses of results from commonly used propagation models applied to UMTS Ultra High Sites in urban environments are presented. Differences between predicted and measured values for a site in Nuernberg are calculated as a function of the distance between base station and mobile station and as a function of the angle of incidence. An assessment of the validity range of the different propagation models is done. Furthermore, an analysis of the accuracy of the classification of building data is presented.

scholarly journals Evaluation of existing DCS1800 and U2100 Indoor Base Station Networks in Multi-storey Buildings in Malang City

2017 ◽  
Vol 5 (2) ◽  
pp. 9-14
Author(s):  
Muhammad Rizal Azizul Hakim
Keyword(s):  
Free Space ◽  
Average Distance ◽  
Base Station ◽  
Transmission Power ◽  
Walk Test ◽  
Test Calculation ◽  
Good For

This study aims to determine the Rx Level value on each floor in the building and determine the omniceiling antenna coverage. Calculation of coverage using the Free Space Loss (FSL) method and measurement with a walk test. Calculation of coverage with the DCS1800 and U2100 networks uses the FSL method to determine the coverage distance per omni ceiling antenna. The result is the farthest distance is 24 meters and the closest distance is 4 meters and the average distance per omni ceiling antenna is 8 meters. As for the results of the walk test on the DCS1800 network, very good results were obtained for the Rx Level value on all floors in the building and for the U2100 network, the results were not good for the Rx Level value on all floors in the building, so it was necessary to evaluate at several points. antenna to improve the quality of the indoor network becomes feasible. In the results of the walk test on the DCS1800 network and the U2100 network, there are several areas in the building that experience bad Rx Level values ??due to poor transmission power so it is necessary to add 1 antenna sector.

scholarly journals A Dual-Band Base Station Antenna with a Split Ring for Sub-6 GHz Communication

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Bei Huang ◽  
Jie Cao ◽  
Weifeng Lin ◽  
Jun Zhang ◽  
Gary Zhang ◽  
...  
Keyword(s):  
Frequency Band ◽  
Free Space ◽  
Base Station ◽  
Dual Band ◽  
Operating Frequency ◽  
Impedance Bandwidth ◽  
Dual Polarization ◽  
Split Ring ◽  
Average Gain ◽  
Frequency Bands

A dual-band base station antenna is introduced in this paper. The proposed antenna is composed of baluns, bowtie patches, and a split ring. The two pairs of bowtie patches excited by the two orthogonal balun structures can achieve dual polarization. The split ring is used to yield two additional resonances to broaden the impedance bandwidth. In this way, a compact dual-band base station antenna is obtained with the size of 0.41 λc × 0.41 λc × 0.13 λc (λc is the wavelength in the free space at the lowest operating frequency band) and the average gain of 8.2 dBi. Moreover, the operating frequency bands of the proposed antenna cover 2515–2675 MHz, 3400–3600 MHz, and 4800–5000 MHz, which can function as an element for macro- or microcells in sub-6 GHz communications.

scholarly journals Determination of Measurement Points in Urban Environments for Assessment of Maximum Exposure to EMF Associated with a Base Station

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Agostinho Linhares ◽  
Antonio José Martins Soares ◽  
Marco Antonio Brasil Terada
Keyword(s):  
Electromagnetic Fields ◽  
Urban Areas ◽  
Base Station ◽  
Urban Environments ◽  
Line Of Sight ◽  
Exposure Limits ◽  
Maximum Exposure

A base station (BS) antenna operates in accordance with the established exposure limits if the values of electromagnetic fields (EMF) measured in points of maximum exposure are below these limits. In the case of BS in open areas, the maximum exposure to EMF probably occurs in the antenna’s boresight direction, from a few tens to a few hundred meters away. This is not a typical scenery for urban environments. However, in the line of sight (LOS) situation, the region of maximum exposure can still be analytically estimated with good results. This paper presents a methodology for the choice of measurement points in urban areas in order to assess compliance with the limits for exposure to EMF.

scholarly journals Analisis kinerja jaringan VANET dengan model propagasi free space dan two ray ground pada routing AODV

Repositor ◽  
2019 ◽  
Vol 1 (2) ◽  
pp. 69
Author(s):  
Adam Tedy Agustin ◽  
Denar Regata Akbar ◽  
Diah Risqiwati
Keyword(s):  
Routing Protocol ◽  
Free Space ◽  
Ad Hoc ◽  
Urban Environments ◽  
Propagation Model ◽  
Delivery Ratio ◽  
Network Simulator ◽  
Mobile Nodes ◽  
Average Value ◽  
Qos Performance

VANET is one type of Ad Hoc network that serves as a wireless network with several mobile nodes that do not have a fixed router. Each of these nodes can function as a router that can search and handle paths to other nodes within a network. Each node on the network is mobile so that the topology of the network is constantly changing. On a network, the routing protocol is something that has a lot of impact on the performance of the network.Each propagation model will certainly have different capabilities and characteristics, therefore it is necessary to research some propagation models in the specified place which will then affect QoS performance on the VANET network. Mobility simulation is done based on urban environment scenario that is around Malang City Hall. This research applies SUMO as mobile simulator and NS-2 as network simulator with AODV type reactive protocol as routing protocol which is used and use propagation model of Free Space and Two Ray Ground as comparison in NS-2.In this research to do QoS analysis with parameters in the test is End to End Delay, Jitter, Packet Delivery Ratio and Throughput. After the data collected, analysis is done by looking at the QoS between the propagation tested. The Free Space propagation model has a smaller delay time with an average of 0.1136 ms than on the Two Ray Ground propagation which has a value of 0.1696 ms. For the number of packets received successfully Free Space propagation is better with an average value of 482.06 kbps throughput compared to Two Ray Ground propagation. The results of testing and analysis prove that Free Space propagation is the right model on the VANET network used in urban environments.

The influence of natural and urban environments on attentional processing of emotional stimuli

2014 ◽  
Author(s):  
Chrono Nu ◽  
Katie Mullin ◽  
Hailey Edwards ◽  
Kailey Kornhauser ◽  
Russell Costa ◽  
...  
Keyword(s):  
Urban Environments ◽  
Emotional Stimuli ◽  
Attentional Processing
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