Interconnecting 2 Locations

Electronics Telecommunications Engineering Student Name – Student ID – Contents Introduction 2 Aim: 2 Discussion of all available options : 3 Technical Specifications : 3 Budget Specifications : 5 Conclusion 7 References 7 Introduction Here, a communication link has been designed for interconnecting 2 locations. Discussion of all available options : Figure 2 ( Light of Sight ) microwave link The data can be communicated between computers using high speed data links ( like fiber optic cables, coaxial cables, microwave , radio links ).

Electronics
Telecommunications Engineering
Student Name –
Student ID –

Contents
Introduction...........................................................................................................................................2
Aim:.......................................................................................................................................................2
Discussion of all available options :.......................................................................................................3
Technical Specifications :.......................................................................................................................3
Budget Specifications :..........................................................................................................................5
Conclusion.............................................................................................................................................7
References.............................................................................................................................................7

Introduction
Here, a communication link has been designed for interconnecting 2 locations. A deep
understanding of digital microwave radio systems is necessary. A microwave link is designed
with path profile construction. The atmospheric effects on the performance of microwave
links are understood. An economic evaluation of the telecommunication systems is done.
The radar system can be used for finding the angle , range or the velocity of an object. It can
be used in the detection of ships, aircrafts, vehicles, missiles etc. The transmitter present in
the system generates the electromagnetic waves ( radio frequency range ). The radio waves
that are transmitted from the transmitter are reflected back from an object towards the
receiver. This gives the information about the location as well as the speed of the object. It
was initially used in military applications.
Nowadays, radar has various uses like traffic control, astronomy, missile systems, marine
systems, meteorology, etc. Radar signal can be processed to find the distance, speed etc. The
interference effects can be reduced by the help of signal processing. There are various radar
frequency bands like HF, VHF, P, UHF, L, S, C, X, Ku, K , Ka, mm, V, W, etc. Wireless
communication can be done by free – space optical communication also. In this system, the
light signal is used to transmit the data wirelessly. The phenomenon used is the Total Internal
Reflection. It can be used in the systems in which the physical connection using wires is not
possible due to high cost involved.
Aim:
To install a direct multimedia communication link between 2 organizations to exchange
voice, data, images, text etc. The 2 organizations are :

• CPA ( Certified Practicing Accountants ) located at 28 Freshwater Pl, Southbank,
Melbourne VIC 3006 and
• Melbourne Institute Technology ( MIT ) located on La Trobe St VIC 3000
Melbourne.
The 2 locations are shown n Figure 1. It shows that the locations are around 2 km
apart.
Figure 1

The technology to be used needs to be decided. As a telecom consultant the possible solutions
( at least two ) have to be proposed for consideration. One of the proposals has to be designed
and implemented.
Discussion of all available options :
Figure 2 LOS ( Light of Sight ) microwave link
The data can be communicated between computers using high speed data links ( like fiber
optic cables, coaxial cables, microwave , radio links ). A microwave radio link has various
advantages like flexibility, fast deployment , lesser cost ( starting as well as operational ),
lower MTTR and absence of ROW issues.
Technical Specifications :
The microwave links are very adaptable since they are broadband. They are capable of
transferring large amount of data at high speeds. Also, they do not require any equipment or
facility between the two terminal points. Hence, it is faster and less costly as compared to a
cable connection. It can be used anywhere but the distance must lie within the operating
range of the system. There must be a clear path ( with no solid obstacle) between the 2
locations. Microwaves can also penetrate rain, fog, and snow. Hence, any bad weather does
not disrupt the transmission process.

The major factors to be kept in mind while planning the design of a microwave link are :
architecture of network ( spur / chain, ring, star, mesh, a combination ), the configuration of
route and choosing the frequency band. In Intracity Route, the access route planning is done
at high frequency bands ( 15, 18, 23 GHz ) with a nominal hop distance of 1 to 10 km. In
Intercity Route, the backbone route planning is done at low frequency bands ( 2 , 6 , 7 GHz )
with a nominal hop distance of 25 – 40 km.
The organisations under consideration are 2.2 km apart. So, intra city route is used.
Figure 3 Microwave Link Design
A Microwave Link Design is shown in Figure 3. The Fresnel zone is identified ( space
between 2 antennas where the radio signal will travel ). Let there be 2 antennas – ‘ X ’and ‘
Ý ’.
The first Fresnel zone distance ( in m) = 17.3 √ ( d1 * d2 ) / f ( d1 + d2 )
Here f = frequency in GHz

. d1 = distance from antenna ‘ X ’ to mid point ( in km )
. d2 = distance from antenna ‘ Y ’ to mid point ( in km )
Height of antenna = H = D2 / 8 + 43.3 √ D / 4 F
Figure 4 Flowchart
The first term is for earth bulge and the second term represents 60 % of the first Fresnel zone.
Here D = distance between antenna
Earth curvature , h = ( d1 * d2 ) / 2
Earth bulge = ( d1 * d2 ) / ( 12.75 * K ) m
K = K factor
. d2 = ( d – d1 ) km
. d = hop distance
Fresnel zone clearance is 30 feet for 10 km path. The clearance for earth’s curvature is 13 feet
for 10 km path.

Budget Specifications :
The microwave network planning process includes various steps : Design basis, Survey line
of sight, link engineering, analysis of interference. In the design basis, the radio equipment is
chosen, various objectives are set and the tower height and load restrictions are set. The Map
needs to be studied properly. The intersection with water body is noted. Antenna height is
then decided based on vegetation height, Fresnel zone depths etc. The field survey is done to
get the relevant data about any obstacles, trees, buildings, power lines etc. The fading
phenomenon which leads to attenuation of the signal is also taken under consideration. The
fading can be : Multipath, frequency selective or rain fading. The rain fading will have an
effect if frequency band is greater than 10 GHz and size of rain droplet is comparable to the
wavelength. Link budgeting, reliability prediction and interference analysis is then done.
R = T – Lx + Gx – F + Gy – Ly
Received level at station ‘ Y ’ = Transmitted power for station ‘ X ’ – Losses at station ‘ X ’
+ Antenna gain at station ‘ X ’ – Free space losses + Antenna gain at station ‘ Y ’ - Losses at
station ‘ Y ’.
The value of ‘ R ’ must be greater than the sensitivity of the receiver ( the lowest possible
signal that can be detected by the receiver ).
Due to interference , the threshold gets degraded ( due to undesired RF signal coupling ) and
the reliability is reduced. A high performance antenna must be used, better specification radio
signal must be used, antenna with high FTB ( Front to Back ) ratio must be used, antenna
height must be such that no LOS for over reach.
The free space loss is given by

F = 92.45 + 20 log ( d.f )
. d = hop distance in km
. f = in GHz
For f = 26 GHz and d = 2 km,
F = 127 dBm
Geo Climatic factor , G = 10 –T * Pl 1.5
Pl = Pl factor
T = terrain factor = 6 ( over large bodies of water )
Antenna Gain = 17.6 + 20 log 10 ( f . d ) dBi
. d = antenna diameter ( m )
. f = GHz ( 60 % efficiency assumed )
A river is present and the terrain factor is taken as ‘6’.
Conclusion
Here, a communication link has been designed for interconnecting the 2 locations. A deep
understanding of digital microwave radio systems has been presented. A microwave link is
designed using the path profile construction. The atmospheric effects on the performance of
microwave links are understood. An economic evaluation of the telecommunication systems

is done. The study has taken into consideration the various factors as per the given location of
the 2 organisations.
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