Final1234 PDF

 

 

CHAPTER I  T HE PROBLEM AND ITS IT S BACKGROUND

1

 

 

CHAPTER I  THE PROBLEM PR OBLEM A AND ND ITS BACKGROUND Introduction Wireless communications is the fastest growing segment of the communications industry. It has captured the interest of engineers and scientist all over the world. (Essays, 2013) Its relevance became a part of the prevailing demand for reliable communications systems and has made a great impact to the world in many important ways. Wireless communications became advantageous especially in connecting people, business managements, research and development, technology for environmental

protection

and

agriculture.

In

the

telecommunication

industry, wireless communications helped in evolving into one of the world’s largest industries during the last decades. The main reasons for

this development are the vast deployment of Internet and new telephone services.

Furthermore,

the

uses

of

microwaves

in

wireless

communications as for transmitting signals in mobile phones and distant geostationary satellites (Singh (Si ngh,, 2016) 2 016) produced satisfactory outcomes.

2

 

 

Wireless technology has been evolving especially in design methods so as to increase reliability and efficiency while diminishing cost. From wireless telecommunication that uses Morses’s telegraph (1837) to Hertz’s first experiment with radio (1887) (Blake, 2000), up to the

discovery of electromagnetic spectrum, there is a giant leap in equipment to improve communication in long distances. The introduction on the use microwave frequencies for communication also became a factor to motivate engineers and scientists to design and to create microwave communication systems. Moving forward, multiple reliable ways for wireless communication were built and implemented. While microwaves are used commonly in microwave ovens for household applications, it can also be used for line-of-sight wireless communication technology (LOS) that uses high frequency beams of radio waves to provide high speed s peed wireless connections that can ca n send se nd and a nd receive voice, video, and data information. (CableFree, 2013) Line of sight serves as a clear path  –  free of any obstructions between points of microwave signal transmission and reception. (Kirk, 2017) A microwave communications circuit can transmit any type of information as efficiently as telephone wires. Microwave communication is nearly 100 percent

3

 

 

reliable (Science Clarified, 2007). The reason is that microwave communication circuits have been engineered to minimize fading, and computer-controlled networks often reroute signals through a different path before a fade becomes noticeable.  As hav have mention mentioned, ed, microwav microwave e commun communication also applies to agriculture. Humanity’s ability to produce enough food in order to sustain

the needs of people mostly depends upon the technologies and methods by the agricultural industries. The use of new studies and research, precision farming technologies, high speed data processing for crop monitoring have enabled men to be capable of transforming the agricultural industry. (Farrell, Jacob, & Brodie, 2016). IoT or Internet of Things has the capability to transform the agricultural technologies through Smart farming as well as TechnoFarming which uses series of ways to elevate the farming methods and crop growth. This made growers and farmers reduce waste and enhance productivity. It is a hi-tech system that bears the application of the Internet and modern ICT (Information and Communication Communicati on Technologies Technologies)) into agricultu agri culture. re. (Ravindra, 2018)  Althou  Alth ough gh

microwav microwave e

commun communication has

a

vast

number number of

applications, most of the time, its purpose depends upon how relevant it is

4

 

 

to the specific site chosen. In a location which most part of its income depends upon its agriculture and local businesses, the microwave communication can be utilized and applied so as to elevate production and help in providing reliable communication among the community

Statement of the the P Problem roblem The agricultural industry in Lumban, Laguna seeks ways to modernize its farming and local businesses also look into promoting and improving its businesses, embroidery in particular and also improving its services. All of these can be achieved by providing internet services. However, the town needs an internet access and communication towers in attaining these goals. In order to make it work, a microwave communication communicatio n tower at Lumban and a nd Los Baños, Laguna, is i s needed. Thus, the aim of this project is to design a microwave antenna to provide internet services to the munici municipali pality ty of Lumban.

5

 

 

Research Questions The proponents sought to answer the central question: Is it feasible to provide a 99.999% reliable microwave link given the design parameters and site consideratio conside rations, ns, environment environmental al factors and and terrain terrai n conditions? conditi ons? Sub-questions: 1.

What are the considerati consid erations ons in designing desi gning the microwave micro wave antenna antenna and how these factors will affect the reliability of the design?

2.

Are the the terrain conditions conditi ons of the path for LOS ideal ide al for the microwave link?

3.

How the specifi spec ificati cations ons of equipment equipme nt will affect the efficiency effic iency and reliability of the microwave link?

4.

What are the the parameters in considering equipment? equipment?

5.

Are the obstructions can be solved? What are the ways and methods to do such?

6.

Is there really a need for the munici municipali pality ty of Lumban for wireless internet through the use of microwave micro wave link?

7.

What are the viewpoints viewpoi nts of residents resi dents of Lumban in implementing imple menting microwave communication within the area?

6

 

 

Objectives Objecti ves o off the Study A. General Objective The main purpose of this study is to provide a 99.999% reliable microwave communication link between Los Baños, Laguna and Lumban, Laguna. The LOS communication system will provide wireless internet services that will serve the town of Lumban particularly its agricultural industry and local business for modernizing farming techniques, increase productivity and businesses profits.

B. Specific Objectives  



To design desi gn a reliable reliab le and efficient effici ent microwave micro wave link system with minimum

losses and acceptable system margin.   



To provide a feasible feasi ble microwave llink ink that that can withstand harsh

environmental conditions.  



To provid provide e relevant data that will provide the need of microwave micro wave

communication link in the Municipality of Lumban.  



To gather vast amount amount of data and interpret such such with the aim ai m to

support the process of designing the link.

7

 

 

 



To identify ide ntify the general standards in designing desi gning the microwave micro wave point-topoi nt-to-

point communications system.  



To establish establi sh a systematic procedure in microwave micro wave communication communicatio n link

design.  



To cater information of different di fferent equipment equipme nt used in designing desi gning a

microwave communication link including their specifications and costing.  



To be knowledgeable knowledgeable of the the general principles and considerations in

designing microwave communications system.

Significance of the Study The design of the microwave link will serve a benefit for different individual in the society regardless of degree and profession. To future engineers, it will serve as guide in planning and designing a microwave link and will provide reliable data for references. To students, the research-based study will also help the Electronics Engineering students who are interested in the concepts of designing Microwave Communications Systems and will improve logical and

8

 

 

analytical thinking in solving design parameters while considering wide range of factors. To professors and instructors, the research will serve as a reference for calculations calcu lations and design procedures to be used used in the the academe. acade me. To stakeholders, the research will provide data as a basis of how there is a need for microwave link communication in a certain area and how these data can ca n be used to project fut future ure growth. To the industry, the research will help in recognizing the benefits and advantages

of

microwave

communications

over

other

transmission

medium. To the researchers, the research will provide accessible information for references and data acquisition. Furthermore, this design is suitable for the province of Laguna, where Los Baños and Lumban are located. This design will serve as a basis for ISP in establishing a backhaul for providing wireless technology in Lumban. This internet technology will help municipality of Lumban particularly the farmers in farming technology. It can also be used in planning on how to uplift and improve farming techniques by aligning it to latest technology, 9

 

 

providing them a reliable and efficient point-to-point communications. It will also help local businesses modernize their services to the tourists and the community. The microwave link will also serve the Municipality of Lumban as a whole for faster and reliable communication.  

Scope and De Deli limit mitations ations In order to identify the parameters that proponents have to consider in designing

the

microwave

link,

the

following

are

the

scopes

and

delimitations. These aim to trim down and to provide boundary of the research.

a. Scope The Th e following are the scope of the the design: desi gn:   The The proposed design d esign is a point to point microwave microwave link link between Los



Baños, Laguna and Lumban, Laguna.   The The proposal propos al tackles the the design desi gn of the microwave micro wave link only. only.



  Physical map used are from NAMRIA NAMRIA and a nd not the most updated edition. edi tion.



10

 

 

  The The system design desi gn is set to operate opera te in the frequency band 7.725Ghz  – 



8.275Ghz.   The The applicati appli cation on of design desi gn is for backhau back haull for WiMax WiMa x internet intended for



use of ISPs.   The The frequency frequency used was based base d on the frequencies frequenci es assigned assi gned by the



National Telecommunicati Telecommunications ons Commis C ommissio sion n (NTC). (NTC).   The The computatio computations ns of coordinates, coord inates, great circle ci rcle distance, di stance, antenna antenna hei height, ght,



panning, losses, point of reflection, reliability, unavailability and link budget are included in the design.   The The terrain elevatio elevation, n, coordinates coord inates plotting and obstruction obstructio n along the path



was based by using ―Path Profile Analysis‖   and confirmed using Google

Earth.   The The equipment equipme nt and their specifi spec ificati cations ons are included.



  The The site layouts layouts for both sites si tes are presented. prese nted.



  The The grounding and and lightning consid considerati erations ons were also presented. prese nted.



  The The different consi considerati derations ons such such as site, frequency, frequency, equipment, tower



and lighting are presented.   The The distan dis tance ce between between the the sites is limited to 30.9 kilometers.



11

 

 

  The The data for the relevance relevance of the the microwave micro wave link design desi gn in the proposed propo sed



site are also presented and interpreted.   The The



recommended

standards

used

were

based base d

on the existing exis ting

international standards.   Information and data gathered about the site was obtained based base d on



internet.   The The constants and formula formula for calculations calculations are based on Fundamentals



of Microwave design by Manny Rule.   Majority of the equipment equipme nt are obtained obtai ned through through the use of internet.



  Data for path profile profi le were confirmed through through Google Earth Ea rth for it was



more updated.   Environmental Environmental consideratio conside rations ns only include average temperature, cloud



and humidi humidity, ty, rainfall rate and wind wind velocity. veloci ty.   Permits and estimated costs for for Construct Construction ion and and Registering Property



were based on internet   The The bill of materials materi als only includes the the equipment. equipme nt.



12

 

 

b. Delimitations   The The microwave design desig n is not implemented on actual field and and on-site on-si te



field survey was not done.   The The bill of materials materi als only includes the the equipment. equipme nt.



  It was was assumed that there there is no no existing microwave communication communicatio n



system in the chosen area and that there are no other microwave links in the vicinity in order to prevent CCI (Co-Channel Interference).   It was was assumed that the establishment estab lishment used for central central office is owned owned by



the proponents.   Maps are not updated updated and all necessary necessary permits were acquired.



  Derivation Deri vation of formula is not included.



  Electrical,



civil

works,

soil

stability,

equipment

configuration

and

architectural layouts layouts were not not included in i n the design. desi gn.   The The return return of investment and future future growth gro wth projection were were not included.



  Equipment Equip ment installation installatio n is not included.



  NTC NTC assigned assi gned the frequency used throughou throughoutt the design. desi gn.



13

 

 

Definition Definit ion o off Terms Antenna   –  is a device that radiates or receives EM waves of certain frequencies.

Attenuation   - the gradual loss of intensity in propagating waves due to disruption or loss in its medium

Atmospheric absorption  - both oxygen and water vapor in the air attenuate microwave signals—and the effect is more pronounced as the link length increases. – is the strength or power Amplitude  – po wer level level of the wave.

Antenna Gain  - is the ratio of how much an antenna boosts the RF signal over a specified low-gain radiator. Antennas achieve gain simply by focusing RF energy.

Atmospheric Losses  - are attenuations due to the absorption of radio frequency energy by oxygen molecules in the atmosphere. These losses can also be defined as attenuations due to the absorption of radio frequency energy by water vapor in the atmosphere.

14

 

 

Azimuth  - The horizontal angular distance from a reference direction, usually the northern point of the horizon, to the point where a vertical circle through a celestial celesti al body intersects intersects the horizon, usually usually measured clockwise. clockwise .

Bandwidth  - is the numerical difference between the upper and lower frequencies of a band of electromagnetic radiation, especially an assigned range ran ge of radio radi o frequencies. frequencies.

Beamwidth - is the the aperture angle from where where most of the power is radiated. radia ted. Bit Error Rate  (BER) - is the percentage of bits that have errors relative to the total number of bits received in a transmission, usually expressed as ten to a negative power.

Center Frequency (Fc)  - is a measure of a central frequency between the upper and lower cutoff frequencies.

Coaxial cable - is a type of electrical cable that has an inner conductor surrounded by a tubular insulating layer, surrounded by a tubular conducting shield. It is used used as a transmission transmissi on line for radio radi o frequency signals. sig nals.

Directivity - a term generally associated with antennas, refers to the ratio of the measured power density densi ty at its peak point, versus the id ideal eal power density. 15

 

 

– (Decibel) The logarithmic unit measuring the ratio of input to output. It is dB   –

generally used as the the unit unit for gain and loss. loss.

dBm - Decibels that are related to 1 mW. The microwave industry uses 1 mW as the standard unit to measure power level.

Earth Bulge  - refers to the number of feet or meters an obstacle is raised higher in elevation owing to earth’s curvature. 

Effective Isotropic Radiated Power   - is the actual RF power as measured in the main lobe (or focal point) of an antenna. It is equal to the sum of the transmit power into the antenna (in dBm) added to the dBi gain of the antenna.

Elevation  - is the height above a fixed reference point, often the mean sea level.

Fade Margin - is the difference between the unfaded receive signal level and the receiver sensitivity threshold. Each link must have sufficient Fade Margin to protect against unexpected system outages.

Fading - refers to the intermittent variation of the transmitted signal or the reduction in i n signal si gnal strength below its nominal level. le vel. 16

 

 

First Fresnel Zone  –  is one of a (theoretically infinite) number of concentric ellipsoids of revolution which define volumes in the radiation pattern of a (usually) circular aperture. Fresnel zones result from diffraction by the circular aperture.

Free space path loss (FSPL) - this is the effect of a signal spreading out as it propagates from the transmitting antenna. This is typically the greatest portion of path loss, accounting for 130 dB or more of losses. Its effects are directly proportional to the link’s distance and the signal’s frequency—as

either increase, so does path loss.

Full Duplex - both parties can communicate with each other simultaneously.  Half-Power Beam width  - it is the nominal total width of the main beam at the -3 dB points, expressing the focus of the strongest part of the beam.

Hertz (Hz)  - a measurement of a signal’s electromagnetic freque ncy, expressed as the number number of cycles per pe r second. seco nd.

Half duplex - a half-duplex (HDX) system provides communication in both directio di rections, ns, but only one direction direc tion at a time (not simult si multaneously aneously). ).

17

 

 

Indoor Unit (IDU) - is mounted in a rack, cabinet, communications room, or even roof-mount shelter as possible possi ble locations. locati ons.

International Telecommunication Union (ITU)  - is an agency of the United Nations (UN) whose purpose is to coordinate telecommunication operations and services throughout the world. Originally founded in 1865, as the International Telegraph Union, the ITU is the oldest existing international organization.

Intermediate Frequency (IF)  –  A frequency to which a carrier frequency is shifted as an intermediate intermediate step in tran transmissi smission on or reception. reception.

Lightning Arrester  –  is a device used on electric power systems and telecommunication systems to protect the insulation and conductors of the system from the damaging effects of lightning.

Line-of-sight  –  A clear path or free of any obstruction between points of microwave microwav e signal transmissio transmission n and reception.. reception..

Link Budget  - is the accounting of all the gains and losses from the transmitter, through a medium (free space, cable, waveguide, fiber optic, etc.) to the receiver recei ver in a telecommunication telecommunicati on system. It takes into account account the

18

 

 

attenuation of transmitted signal due to propagation, as well as the loss, or gain due to the antenna.

Microwave  - refers to electromagnetic energy having a frequency higher than 1 gigahertz (billions of cycles per second), corresponding to wavelength shorter than 30 centimeters.

Microwave Link  - is a high frequency link specifically designed to provide signal connection connection between two specific points.

Modulation  - is the process of varying one or more properties of a periodic waveform, called the carrier signal, with a modulating signal that typically contains information to be transmitted.

Obstruction Light  –  a light indicating the presence of an object which is dangerous to an aircraft in flight.

Outdoor Unit (ODU) - is typically mounted directly to the Microwave Antenna on a rooftop or tower location.

Path Profile  - is a graphical representation of the path travelled by the ratio waves between the two ends of a link. The path profile determines the location and height of the Antenna at each end of the link, and it insures that 19

 

 

the link is free of obstructions, such as hills, and subject to propagation losses from radio phenomena, such as multipa multipath th reflection. reflectio n.  – is the orientation of the electric field driving the wave. Polarization –

QAM QA M  (quadrature amplitude modulation) - A modulation technique that employs both phase modulation (PM) and amplitude modulation (AM). QAM doubles the effective bandwidth by combining two amplitude-modulated signals into a single channel. This allows multiple analog signals to be placed on a single carrier.

Radiation

pattern

envelope

(RPE)  –  The

guaranteed

electrical

characteristics of the antenna. It is a line drawn over the peaks of the main lobe, side lobes and back lobes in horizontal and vertical polarization. It covers both co-and cross polarization performance.

Radome - a protective plastic or fabric cover fitted to the front of a microwave antenna. Some feature hydrophobic designs that repel water, snow and ice, and can reduce the antenna ’s wind load. 

Redundancy  – a system design in which a component is duplicated so if it fails there will be a backup. This increases reliability.

20

 

 

Receive Signal Level  - is the expected strength of a signal when it researches the receiving radio

Rainfall (mm)  - The amount of precipitation (rain, hail, etc.) expressed in millimeters depth, of the layer of the layer of the water has fallen.

Rainfall Attenuation  - is a phenomenon relative to the rainfall rate and frequency which results in increasing path loss, limiting the coverage area, and consequently degradi degra ding ng the system performance. performance .

Reliability  - refers to the amount of time that a communication system is accessible to the general public

Split Mount  –  radio configuration which electronics are split into an outdoor unit (ODU) and indoor unit (IDU), eliminating transmission line losses with easy maintenance of the IDU.

Signal-to-noise Ratio  - is the ratio (usually measured in dB) between the signal level received and the noise floor level for that particular signal.

System Gain  - is the difference between the nominal output power of a transmitter and the minimum input power required by receiver.

21

 

 

Unavailability   - is an expression of the degree to which a system, subsystem, or equipment is not operable and not in a committable state at the start of a mission, when the mission is called for at an unknown random time.

Wind load - the amount of force experienced by an exposed structure due to winds common to its location. It is directly related to wind speed, which can be affected by the height and terrain of that location.

22

 

 

CHAPTER II  RELATED STUDIES AND LITERATURE

23

 

 

CHAPTER II RELATED STUDIES AND LITERATURE LITERATURE I.

Related Studies

A. Local The parameters and considerations of microwave communication link design will a determining factor in how reliable the system is when establish and implemented. In a study conducted by Alipio et. al, a point to point 31.34 km microwave communication link connecting Cabuyao City, Laguna and Sta. Cruz, Laguna was made with 99.999% reliability. The study designed a two-hop full-duplex analog microwave communication link for the given sites. This study was done systematically and in comparative for both hops based on a process of designing a microwave link which includes path profiling, transmission calculations, and system reliability calculations. Economical aspect which includes project costs and engineering economy assumptions were also considered in this study. (Alipio, Oracion, & Manuel, 2009-2010) The achievement of 99.99% reliability was based on the usual parameters with extensive study and research.

24

 

 

The same considerations were also used in the establishment of the microwave communication link design connecting PLDT-Brgy. Casmisehos, Canlubang, Laguna and PLDT-Brgy. Maduya, Carmona, Cavite for voice and data transmission. The study which was conducted by Montoya, Malanay and Fernandez used descriptive research method to describe and analyze the factors that could affect the design. These include the path profile, link budget, land elevation, elevatio n, azimuth and analysis analysis of atmospheric atmospheri c conditio condition. n. ITU-R TU-R recommendation of 7.25-7.55 Ghz was used. The microwave link design had a path length of 12.62 km. The line of sight could be poor if there would be any obstruction higher than the elevation of both sites. (Montoya, Malanay, & Fernandez, 2009-2010) These obstructions were only assumed and were based on the topographical map. The study proved the feasibility of creating a microwave link on the said site. In a microwave communication link built and implemented for Wyeth Philippines Inc. connecting its main plant and warehouses in Silangan, Cabuyao served as a medium of transmission for voice, data and video information. The main purpose of the design was for the benefits of company in terms of its productions and other means of business. The study used descriptive method and in consideration of different factors to come up with a cost-efficient and reliable design. Mathematical calculations and analysis of  25

 

 

acquired data were done to test the feasibility and determine the different parameters in the study. Although thermal fade margin was the greatest factor

in

the

microwave

link,

a

reliability

of

99.99999511%

and

99.99999528% for low band and high band frequency respectively were attained. (Banaticla, Guno, & Herradura, 2010) In a proposed point-to-point microwave link by Bicongco, Santiago and Saludo for transport of audio and video of national broadcasting network local studio, it was stated that the considerations of environmental effects became a determining factor in calculating the reliability of the design. Thermal fade margins and rain attenuation was 25.1127 dBm and 30.7118 dBm for low and high band frequency respectively. (Biconco, Santiago, & Saludo, 2009-2010). The calculated rain attenuations were 18.2348 dB and 14.9351 dB for low and high frequency respectively. After considerations of effects and factors for the design, the proponents came up with Ericson Mini Link TM radio equipment as the best fit for the implementation of the microwave link. It also single-hope design which were two 6 feet HPX6-70  Andrew  Andr ew Anten Antenna na,, standard standard hangers, angers, gray-w gray-wh hite radome, and EW64 elliptical elliptical waveguide, all from Andrew Antenna and the Harris Truepoint 5000 digital radio. These specifications were based on the calculated parameters which considered the relevance of pre-determined factors. Furthermore, the 26

 

 

designed followed the standards and rules promulgated by National Telecommunications Commission in designing such link. The reliability of the design was 99.99998% considering all probable conditions and future situations that may arise. These local studies proved that reliability of almost 100% is possible by of course considering a number of factors. If the previous studies were able to do so, designing microwave link for Los Baños and Lumban can be feasible.

B. Foreign Wireless systems have always been susceptible to interception in both urban outdoor and indoor environments. In point-to-point communication links, the placement of base station antennas is usually determined by an experimental or analytical assessment of the propagation path. Since pointto-point links are typically used to network widely separated areas, antennas used in such situations are likely to be directional, but may still be susceptible suscepti ble to interception interceptio n by covert covert entiti entities. es.

In order to to compensate compe nsate the

problems that can be encountered in designing microwave antenna links, planning and organization of creating the design parameter should be

27

 

 

observed. According to Al Mahmud and Khan in his study ― Analy  Analysis sis and and Planning Microwave Link to Established Efficient Wireless Communications ‖, wireless communication is observing a fast development in today’s communication era. Therefore, analysis and planning of a microwave link is very much important. The microwave equipment can be installed after a careful planning and detailed analysis a microwave radio system. A poorly designed path can result in periodic system outages, resulting in increased system latency, decreased throughput, or worst case, a complete failure of the system. Planning a good, stable and reliable microwave network can be quite challenging. At the same time, it poses several interesting optimization problems. (Al Mahmud & Khan, 2010). It was also cited in the study of Al Mahmud and Khan that even though designing microwave links is a critical and complex process (considering vast factors), eventually provides a number of advantages over fiber based transmission. Microwave link can be installed in one day due to its rapid deployment. Microwave also offers less fading since the wave transmission from transmitter to receiver takes place in line-of-sight propagation. It can also overcome railways, road and ponds avoiding taking any permission to establish the communication link thus preventing additional cost and delay. 28

 

 

Microwave also offers the best solution for cities that prohibit and restricting street digging to install cable or fibers. It is flexible, reliable in natural disasters and has negligible operational costs. Prevention and solution for different problems and deficiencies in designing a microwave antenna can be viewed as challenging and requires research and thorough analysis. In 1962, Shackelford analyzed the effects of radiation patterns of microwave antenna is the far field region. The radiation patterns are analyzed and the effects were determined by analytical methods. The study aimed to devise a technique to determine the effects of on the far zone of these radiation patters of microwave antenna caused by the signal source’s being in the

Fresnel zone. The technique will haven effect in selecting antenna aperture and dimensions. It will help in determining the reliability of equipment especially

a

microwave

antenna

when

propagating

microwaves.

(Shackelford, 1962)  Altho  Alt houg ugh h in modern times, microwav microwave e commun communication poses several several interesting application it brings problems especially in power efficiency and to the environment.  A study study presented presented by Chavez Chavez-Go -Gomez mez et.al, et.al, optimizing optimizing the the energy consumption of wireless telecommunications infrastructure has become a new challenge for the research community, governments and 29

 

 

industries in order to reduce CO2 emission and operational energy costs, the power consumption of indoor/outdoor Wireless Access Devices (WADs, specifically WiFi and WiMAX access points) and provides novel techniques for improving the energy efficiency of wireless access networks. (ChavezGomez, Riggio, Rasheed, & Granelli, 2011). However, problems in power efficiency can be solved in using HPM devices or Efficient High Power Microwave radiating systems. In a study by Khan et. al, Efficiency of HPM antenna can be improved by varying its physical shape and dielectric used in it. The most critical location in an HPM antenna is its interface from where microwave leaves and enters into the air. The performance of HPM antenna depends upon equipment design and composition. (Khan, Mansoor Ahmed, Rafiq, & Rafique, 2016) The studies presented were some of the basis of the proponents in determining the appropriate and efficient design for a microwave link. The reliability of the previous studies can serve as a platform of how possible an almost 100% reliable microwave link is upon consideration of course of several factors that will have a great impact on the outcome of the design.

30

 

 

II. Related Literature A.

Local

Manny

T.

Rule

provides

a

guide

in

designing

a

Microwave

Communications System. He considered the microwave radio specifications, frequency band to be used, and topographical map of the link, available channel plans and minimum site elevation. He discussed the factors that affect the signal including interference, multipath fading due to reflection, multipath fading due to refraction, diffraction due to path obstructions, multipath fading due to ducting and multipath fading due to rain. The environmental conditions were also considered in creating antenna design. (Rule, 2000) The relevance of microwave link and its implementation leads to reliable voice, video and data transmission. The latter is an important factor in several agricultural applications and business management. In the paper published by Rionel Belen Caldo about Smart Farming, he said that smart farming in the country could empower local farmers with the decision tools and technologies technologies needed for thei theirr livelihood. However, However, this technology technology is not not

31

 

 

yet available in the country. For sustainable agriculture in midst of climate change, monitoring of plant health and detecting its diseases is critical. The need to effectively grow a plant and increase its productivity should be given emphasis. In addressing these concerns, monitoring and grading the plant at its growth and at the time of its harvest harvest is i s necessary. (Caldo, (Caldo , 2016)

 Anoth  Anot her evident evident reason how techn technology can modern modernize farming farming is its application in monitoring crop growths. In Lumban, Laguna, Tehno-demo farm was established in an effort to revitalize vegetable production and assists farmers in gaining knowledge about modern farming methods. Techno-demo farm was used as a learning field for farmers to see how technology can improve their usual practice. By these, farmers no need to go to research centers to acquire necessary information and skills in modern farming. Technology Technology is utilized utili zed to modernize farming indu i ndustry. stry. This This can help in maintaining food security in respective areas. (Yap, 2016) Of course as part of this program, the technology has to be reliable especially if monitoring plant growth involves the transfer of data acquired for monitoring through the use of internet. There is also a risk if reliable communication between farmers in large farm fields is not maintained. In an attempt to modernize farming industry, there is a great investment involved 32

 

 

in implementing communication towers for data, voice and video. Lumban, Laguna prosper also in tourism. As the ―Embroidery Capital of the   Philippines‖, it is also rich in export -quality items which makes the locals

invest in businesses of making embroideries. Furthermore, it is a home of tourism spots such as natural waterfalls and resorts. These boost tourism industry and profit of the community. As the town progresses in tourism due to its products and resorts, the demand for quality services also increases. The services of the local businesses can be further modernized by creating a microwave

link

to

serve

the

community

with

internet

and

reliable

communication. However, even before the application of microwave links in farming or in local businesses for management, the design and planning of microwave antenna antenn a is strictly done do ne to to produce promising promis ing results. The parameters can be well calculated and extensive research can be done in order to achieve 99.99% reliability thus helping out the community and achieving the goals needed.

33

 

 

B. Foreign The agricultural sector vastly improved as the application of the internet was utilized in using technology to farming industries. According to Mitesh Patel, efficient management, optimized use of seeds and fertilizers along with precise and continuous monitoring can make this task achievable. It was made possible by the use of IoTs. Internet in farming provides real-time information which increases production through taking informed farming decisions. The internet-enabled objects and sensors can be deployed anywhere to gather data on moisture level and crop health. The farmers can easily gather the data through their tablets and mobile phones. (Patel, 2018) When it comes to farming solutions, internet technology is important. This poses an extremely important idea of creating microwave antennas to places which have to be catered with internet services and data transmission. Those places whose primary profit comes from agricultural sector have a need for this kind of technology. Though the design and establishment of microwave antenna is by theory easy and attainable, there are two fundamental aspects of wireless communication that make the problem challenging and interesting. According to David Tse Tse in i n his his book bo ok Fundamen Fundamentals tals of Wireless Wire less Communicatio Communications, ns, these 34

 

 

aspects are by and large not as significant in wire-line communication. First is the phenomenon of fading: the time-variation of the channel strengths due to the small-scale effect of multipath fading, as well as larger scale effects such as path loss via distance attenuation and shadowing by obstacles. Second, unlike in the wired world where each transmitter-receiver pair can often be thought of as an isolated point-to-point link, wireless users communicate over the air and there is significant interference between them in wireless communication. The interference can be between transmitters communicating with a common receiver (e.g. uplink of a cellular system), between signals from a single transmitter to multiple receivers (e.g. downlink of a cellular system), or between different transmitter-receiver pairs (e.g. interference between users in different cells). (Tse, 2014) Microwaves display some interesting propagation characteristics making them an ideal transmission medium. Line of sight inks are costeffective especially in the transfer of large amount of data in long distances. The use of copper or fiber optic infrastructure is costly and so microwave communications answer that problem. It’s   easy to install equipment and network operators don’t rely on third party vendors to deploy expensive

cables/. The use of microwave antenna in propagating information for long

35

 

 

distance

transmission

proves

connectivity

better

suited

for

urban

environments and of course for rural places where commercial networks are hard to reach. (Kurk, 2017)

Theoretical Framework Design and implementation of microwave link between two locations which are separated by long distance demands understanding of principles and concepts of microwave communications. Although resources are readily available and vast learning websites about designing the link can be easily accessed, the process itself is still complex and every consideration has to be critically studied. The reliability of such links depends upon the equipment used, the design and site considerations and also how both stations are constructed. The feasibility of designing a microwave link is also affected by costing and availability of equipment that will fit the parameters set and calculated. In a study by Rakib Al Mahmud and Zaigham Shabbir Khan entitled ―Analysis and Planning Microwave Link to Established Efficient Wireless Communications‖, it was stated that the activities of path planning and

frequency planning preferably should performed in parallel with line of sight activities and other network design activities for better efficiency. The uses of 36

 

 

the most updated maps are also recommended (not more than a year old) since terrains can change drastically in a short period of time. Although most of the previous designs of microwave links were feasible and practical when implemented, this varies when it comes to where the locations of the two sites are. Remember that as location varies, some of the environmental and terrain considerations also change though the process of designing the microwave links are also the same. However, all designs aim the same thing, reliable, efficient and cost-effective point-to-point communication system.

Concept Conce pt of WiMax WiMax In practical terms, WiMAX would operate similar to WiFi but at higher speeds, over greater distances and for a greater number of users. WiMAX could potentially erase the suburban and rural blackout areas that currently have no broadband Internet access because because phone an phone and d cable companies have not yet run the necessary wires to those remote locations.

 A WiMAX system system consists consists of two two parts:  A WiMAX tower, tower, similar in concept concept to a cell-ph cell-phon one e tower tower - A single single WiMAX tower can provide coverage to a very large area -- as big as 3,000 square miles (~8,000 square km). 37

 

 

 A WiMAX receiver receiver - The The receiver receiver and and anten antenna na could could be a small small box or PCMCIA card, or they could be built into a laptop the way WiFi access is today.

 A WiMAX tower tower station station can connect connect direct di rectly ly to the the Intern ternet using a highbandwidth, wired connection. It can also connect to another WiMAX tower using a line-of-sight, microwave link. This connection to a second tower (often referred to as a backhaul), along with the ability of a single tower to cover up to 3,000 square miles, is what allows WiMAX to provide coverage to remote rural areas.

What this points poi nts out is that that WiMAX Wi MAX actually can

provide two forms of wireless service:

There is the non-line-of-sight, WiFi sort of service, where a small antenna on your computer connects to the tower. In this mode, WiMAX uses a lower frequency range -- 2 GHz to 11 GHz   (similar to WiFi). Lowerwavelength

transmissions

are

not

as

easily

disrupted

by

physical

obstructions -- they they are a re better able a ble to diffract, or bend, around around obstacles. obstac les.

There is line-of-sight service, where a fixed dish antenna points straight at the WiMAX tower from a rooftop or pole. The line-of-sight connection is stronger and more stable, so it's able to send a lot of data with fewer errors. 38

 

 

Line-of-sight transmissions use higher frequencies, with ranges reaching a possible 66 GHz. At higher frequencies, there is less interference and lots more bandwidth.

WiFi-style access will be limited to a 4-to-6 mile radius (perhaps 25 square miles or 65 square km of coverage, which is similar in range to a cell-phone zone). Through the stronger line-of-sight antennas, the WiMAX transmitting station would send data to WiMAX-enabled computers or routers set up within the transmitter's 30-mile radius (2,800 square miles or 9,300 square km of coverage). This is what allows WiMAX to achieve its maximum range. When it comes to the variables that will affect the design, there are a number of these variables that have to be determined prior to implementation of the design in the actual field. These may be grouped as dependent and independent variables.

39

 

 

WiMA WiMAX X - IEEE Standards Interface for Fixed Broadband Wireless The IEEE 802.16, the Air Interface  Access Systems , also known as the IEEE WirelessMAN air interface, is an

emerging suite of standards for fixed, portable and mobile BWA in MAN. These standards are issued by IEEE 802.16 work group that originally covered the wireless local loop (WLL) technologies in the 10.66 GHz radio spectrum, which were later extended through amendment projects to include both licensed

and un unlice licensed nsed spectra spe ctra from 2 to 11 GHz. GHz.

The WiMAX umbrella currently includes 802.16-2004 and 802.16e. 802.16-2004 utilizes OFDM to serve multiple users in a time division fashion in a sort of a round-robin technique, but done extremely quickly so that users have the perception that they are always transmitting/receiving. 802.16e utilizes OFDMA and can serve multiple users simultaneously by allocating sets of tones to each user.

40

 

 

Table 2.1 IEEE 802.16 8 02.16 Standards related to WiMAX.

802.16

802.16a

802.16e

Spectrum

10-66GHz

2-11GHz