This document provides training materials on calculating wireless link budgets to determine the feasibility and optimal configuration of radio links. It defines key concepts like free space loss, link budget, antenna gain and Fresnel zone. An example link budget calculation is shown for a 5km link. It also introduces the Radio Mobile software tool, which can automatically simulate radio links and calculate the required Fresnel zone clearance by considering terrain profiles. The document concludes with an example of using Radio Mobile to analyze a potential link in Chuuk and poses questions about configuring the masts, transmit power and antennas.
Satellite Link Design:
EIRP, Transmission Losses, Free-space transmission, System noise temperature and G/T ratio, Noise figure, Design of downlinks, Design of uplink, Design of specified C/N: combining C/N and C/I values in satellite links, Overall C/No, Link design procedure.
Satellite Link Design:
EIRP, Transmission Losses, Free-space transmission, System noise temperature and G/T ratio, Noise figure, Design of downlinks, Design of uplink, Design of specified C/N: combining C/N and C/I values in satellite links, Overall C/No, Link design procedure.
A presentation on RF survey, showing how survey of a cell site is done, how a microwave link is established, and how to perform the LOS survey for clearing the obstacles in between the links
Fundamental of Radio Frequency communications.pptginanjaradi2
Fundamentals of Radio Frequency (RF) communications encompass the principles and techniques used to transmit and receive information wirelessly using electromagnetic waves within the radio frequency spectrum. Here's a breakdown of the key components:
1. **Electromagnetic Spectrum**: RF communications utilize a portion of the electromagnetic spectrum. This spectrum ranges from low frequencies used for power transmission to high frequencies used in technologies like microwaves and beyond. RF typically occupies the frequency range from about 3 kHz to 300 GHz.
2. **Modulation**: Modulation is the process of impressing information onto a radio wave by varying one or more of its properties such as amplitude, frequency, or phase. Common modulation techniques include Amplitude Modulation (AM), Frequency Modulation (FM), and Phase Modulation (PM).
3. **Transmitters**: Transmitters generate radio frequency signals carrying the information to be transmitted. They typically consist of an oscillator to produce the carrier frequency, modulation circuitry to impress the information onto the carrier, and amplifiers to boost the signal for transmission.
4. **Receivers**: Receivers capture radio frequency signals, extract the desired information, and convert it into a usable form. Receivers include components such as antennas to capture the incoming signal, amplifiers to boost weak signals, demodulators to extract the information from the carrier, and filters to remove unwanted noise and interference.
5. **Antennas**: Antennas are crucial components for both transmitting and receiving RF signals. They convert electrical signals into electromagnetic waves for transmission and vice versa for reception. Antennas come in various designs optimized for different applications, such as dipole antennas, patch antennas, and parabolic antennas.
6. **Propagation**: RF signals propagate through the atmosphere, and their behavior is influenced by factors such as frequency, distance, terrain, and environmental conditions. Understanding propagation characteristics is essential for designing efficient communication systems.
7. **Propagation Models**: Propagation models describe how RF signals propagate in different environments. These models help engineers predict signal strength, coverage areas, and potential sources of interference. Common models include free-space path loss, multipath fading, and terrain-based models.
8. **Spectrum Management**: Since the radio frequency spectrum is a finite and shared resource, its allocation and usage are regulated by government agencies such as the Federal Communications Commission (FCC) in the United States. Spectrum management involves allocating frequency bands to different users, enforcing regulations to prevent interference, and promoting efficient spectrum utilization.
9. **Applications**: RF communications find applications in various fields, including broadcasting, telecommunications, wireless networking.
System Consideration, Design and Implementation of Point To Point Microwave L...ijtsrd
Microwave technology is extremely used for point to point communications because it is more easily focused into narrower beams than radio waves, allowing frequency use, it is available higher data transmission rates and antenna sizes are smaller than at lower frequencies. The main aim of this system is to provide internet access for rural area using ePMP Force 180 5GHz subscriber module. The two sites are 1.45 km away from each other. GPS is used to determine the latitude and longitude of two sites location. Google Earth Pro software is used to check for line of sight in choosing potential terminal site locations. In this system, system consideration, design and analysis of line of sight microwave link and hardware implementations are to be carried out. In the analysis, path profile, Fresnel zone, link budget and other parameters are implemented using the link planner software Lay Nandar Soe | Kyaw Thet Zaw | Wai Phyo Aung "System Consideration, Design and Implementation of Point-To-Point Microwave Link for Internet Access" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-5 , August 2019, URL: https://www.ijtsrd.com/papers/ijtsrd26769.pdf Paper URL: https://www.ijtsrd.com/engineering/electronics-and-communication-engineering/26769/system-consideration-design-and-implementation-of-point-to-point-microwave-link-for-internet-access/lay-nandar-soe
Third Generation Wireless Modeling in Urban EnvironmentEECJOURNAL
The global mobile communication is fast growing in industry. This paper recommends appropriate settings to evaluate the performance of wireless mobile system deploying third generation networks in an urban environment. To meet this aim, a case Study of Sulaimanyia city is considered for this study by establishing suitable radio channel models. The work presents a statistical channel model, where fixed and nomadic analysis services are considered in the simulated radio coverage scenario. The cartographic dataset had been collected, and Matlab Software was used for showing the analysis and simulation results. Statistical channel models are derived that combine standard parameters such as separation distance, operating frequency and terminal height with more advanced and innovative parameters such as distance dependent shadowing and LOS probability.
During PMRExpo - the leading European exhibition in professional mobile radio communications that was held in Coloigne from 26 to 28 December 2017 - Alessandro Guido, Leonardo DMR Systems Design, participated in the Workshop Digital Mobile Radio Association DMR" discussing "How to build a DMR Simulcast Network".
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
Acetabularia Information For Class 9 .docxvaibhavrinwa19
Acetabularia acetabulum is a single-celled green alga that in its vegetative state is morphologically differentiated into a basal rhizoid and an axially elongated stalk, which bears whorls of branching hairs. The single diploid nucleus resides in the rhizoid.
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Biological screening of herbal drugs: Introduction and Need for
Phyto-Pharmacological Screening, New Strategies for evaluating
Natural Products, In vitro evaluation techniques for Antioxidants, Antimicrobial and Anticancer drugs. In vivo evaluation techniques
for Anti-inflammatory, Antiulcer, Anticancer, Wound healing, Antidiabetic, Hepatoprotective, Cardio protective, Diuretics and
Antifertility, Toxicity studies as per OECD guidelines
2. 2
Goals
‣ To be able to calculate
how far we can go with
the equipment we have
‣ To understand why we
need high masts for
long links
‣ To learn about software
that helps to automate
the process of planning
radio links
3. Free space loss
‣ Signal power is diminished by geometric spreading of
the wavefront, commonly known as Free Space Loss.
‣ The power of the signal is spread over a wave front, the
area of which increases as the distance from the
transmitter increases. Therefore, the power density
diminishes.
Figure from http://en.wikipedia.org/wiki/Inverse_square 3
4. Free Space Loss (@2.45 GHz)
‣ Using decibels to express the loss and using 2.4 GHz
as the signal frequency, the equation for the Free
Space Loss is:
Lfs = 100 + 20*log(D)
‣ ...where Lfs is expressed in dB and D is in
kilometers.
4
5. Free Space Loss (any frequency)
‣ Using decibels to express the loss and using a generic
frequency f, the equation for the Free Space Loss is:
Lfs = 32,45 + 20*log(D) + 20*log(f)
‣ ...where Lfs is expressed in dB, D is in kilometers and f
is in MHz.
5
8. Link budget
‣ The performance of any communication link depends on the
quality of the equipment being used.
‣ Link budget is a way of quantifying the link performance.
‣ The received power in an 802.11 link is determined by three
factors: transmit power, transmitting antenna gain, and
receiving antenna gain.
‣ If that power, minus the free space loss of the link path, is
greater than the minimum received signal level of the
receiving radio, then a link is possible.
‣ The difference between the minimum received signal level and
the actual received power is called the link margin.
‣ The link margin must be positive, and should be maximized
(should be at least 10dB or more for reliable links).
8
10. Example link budget calculation
10
Let’s estimate the feasibility of a 5 km link, with one
access point and one client radio.
The access point is connected to an antenna with 10
dBi gain, with a transmitting power of 20 dBm and a
receive sensitivity of -89 dBm.
The client is connected to an antenna with 14 dBi gain,
with a transmitting power of 15 dBm and a receive
sensitivity of -82 dBm.
The cables in both systems are short, with a loss of 2dB
at each side at the 2.4 GHz frequency of operation.
11. AP to Client link
11
+10 dBi
-2 dB
+20 dBm
+14 dBi
-2 dB
-82 dBm
??
?
-114 dB @ 5 km
12. Link budget: AP to Client link
12
20 dBm (TX Power AP)
+ 10 dBi (Antenna Gain AP)
- 2 dB (Cable Losses AP)
+ 14 dBi (Antenna Gain Client)
- 2 dB (Cable Losses Client)
40 dB Total Gain
-114 dB (free space loss @5 km)
-73 dBm (expected received signal level)
--82 dBm (sensitivity of Client)
8 dB (link margin)
14. Link budget: Client to AP link
14
15 dBm (TX Power Client)
+ 14 dBi (Antenna Gain Client)
- 2 dB (Cable Losses Client)
+ 10 dBi (Antenna Gain AP)
- 2 dB (Cable Losses AP)
35 dB Total Gain
-114 dB (free space loss @5 km)
-78 dBm (expected received signal level)
--89 dBm (sensitivity of AP)
10 dB (link margin)
15. Fresnel Zone
‣ The First Fresnel Zone is an ellipsoid-shaped volume
around the Line-of-Sight path between transmitter and
receiver.
‣ The Fresnel Zone is important to the integrity of the RF
link because it defines a volume around the LOS that
must be clear of any obstacle for the the maximum power
to reach the receiving antenna.
‣ Objects in the Fresnel Zone as trees, hilltops and
buildings can considerably attenuate the received signal,
even when there is an unobstructed line between the TX
and RX.
15
16. 16
Line of Sight and Fresnel Zones
a free line-of-sight IS NOT EQUAL TO a free Fresnel Zone
r
17. Fresnel Zone
‣ The radius of the first Fresnel Zone at a given point
between the transmitter and the receiver can be
calculated as:
‣ ...where r is the radius of the zone in meters, d1 and d2
are distances from the obstacle to the link end points in
meters, d is the total link distance in meters, and f is the
frequency in MHz.
‣ Note that this gives you the radius of the zone, not the
height above ground. To calculate the height above
ground, you need to subtract the result from a line drawn
directly between the tops of the two towers.
r = 17.31 * sqrt((d1*d2)/(f*d))
17
18. 18
Line of Sight and Fresnel Zones
r = 17.31 * sqrt((d1 * d2) / (f * d))
rMAX
d1 d2
r
19. Clearance of the Fresnel Zone and
earth curvature
Distance
(km)
1st zone
(m)
70%
(m)
Earth curvature (m)
Required
height (m)
1 5.5 3.9 0.0 3.9
5 12.4 8.7 0.4 9.1
10 17.5 12.2 1.5 13.7
15 21.4 15.0 3.3 18.3
20 24.7 17.3 5.9 23.2
25 27.7 19.4 9.2 28.6
30 30.3 21.2 13.3 34.5
This table shows the minimum height above flat ground required to
clear 70% of the first Fresnel zone for various link distances at 2.4
GHz.
Notice that earth curvature plays a small role at short distances, but
becomes more important as the distance increases.
19
20. Fresnel Zone
‣ Considering the importance of the Fresnel Zone, it
is important to quantify the degree to which it can
be blocked.
‣ Typically, 20% - 40% Fresnel Zone blockage
introduces little to no interference into the link.
‣ It is better to err to the conservative side allowing
no more than 20% blockage of the Fresnel Zone.
20
21. Radio Mobile
‣ Radio Mobile is a free tool to aid in the design and
simulation of wireless systems.
‣ It can automatically calculate the power budget of
a radio link, calculating the Fresnel zone
clearance. It can use digital maps, GIS
(Geographical Information Systems), or any other
digital map, including maps provided by yourself.
‣ Runs on Windows 95, 98, ME, NT, 2000 and XP.
21
http://www.cplus.org/rmw/english1.html
22. Radio Mobile
22
‣ Uses Digital terrain Elevation Model for the calculation of
coverage, indicating received signal strength at various point
along the path.
‣ Radio Mobile automatically builds a profile between two
points in the digital map showing the coverage area and 1st
Fresnel zone.
‣ Different antenna heights can be tried to achieve optimum
performance.
24. Win vs Web Radio Mobile
24
‣ Web version
‣ Pros: runs on any machine (Linux, Mac, Tablet);
does not require big downloads; saves sessions;
user friendly
‣ Cons: requires connectivity; only certain
frequencies
‣ Windows version
‣ Pros: runs offline; can use the GPS
‣ Cons: runs on Windows only; requires big
downloads; hard to learn
38. Chuuk link
38
Questions to answer:
1) How high should the masts be?
2) How much output power should the radio give?
3) What antennas should we use?
Please use the equipment in the lab to answer.
39. For more details about the topics presented
in this lecture, please see the book Wireless
Networking in the Developing World,
available as free download in many
languages at:
http://wndw.net/
Thank you for your attention
