Designing High-Speed Wireless Data Link: Line of Sight Link Budget

This report presents a comprehensive analysis of a line-of-sight (LOS) link budget for a high-speed wireless data link. It begins by calculating the Free Space Path Loss (FSPL) in dB for distances of 5km and 10km at frequencies of 2.4GHz and 5.8GHz, summarizing the results in a table. Subsequently, the report performs a link budget analysis for a wireless system operating at 5.8GHz with a point-to-point link type, calculating the received power and link margin based on given parameters like transmit power, antenna gain, and receiver sensitivity. The analysis determines whether the link budget is adequate for reliable data transmission. Finally, the report assesses the availability/reliability of the link at 5km based on the calculated link margin, referencing a table that relates link margin to time availability percentages, concluding that the link margin is sufficient for a high percentage of link availability. The document is available on Desklib, a platform offering AI-based study tools and a wide range of solved assignments.

A.
Calculate the FSPL in dB for a distance of 5Km and 10Km for two different frequencies
5.8GHZ, 2.4GHz and construct a table as follows:
FSPL(dB)
Distance (Km) 2.4GHz 5.8GHZ
5
10
FSPL – free space path loss is proportional to the gap and frequency. In alternative words, FPSL
is proportional to the sq. of the frequency of the radio emission and yet because it is proportional
to the square of the gap between the transmitter and also the receiver.( Idc-onlinecom. 2019.)
The FSPL in sound unit for a distance of 5Km and 10Km for 2 totally different frequencies
5.8GHZ, 2.4GHz is calculated as follows:
Formula:
FPSL (dB) = 20 log10 (d) + 20 log10 (f) +32.45
The FSPL in dB for a distance of 5Km and for the frequency of 2.4GHz is calculated as follows:
For 2.4GHz,
At, d=5 Km
FPSL (dB) = 20 log10 (5) + 20 log10 (2.4G) +32.45
= 13.9794 + 187.60 + 32.45
= 234.02 dB
The FSPL in dB for a distance of 10Km and for the frequency of 2.4GHz is calculated as
follows:
At, d=10 Km
FPSL (dB) = 20 log10 (10) + 20 log10 (2.4G) +32.45
= 20 + 187.60 + 32.45
= 240.05 dB
For 5.8GHz,

The FSPL in dB for a distance of 5Km and for the frequency of 5.8GHz is calculated as follows:
At, d=5 Km
FPSL (dB) = 20 log10 (5) + 20 log10 (5.8G) +32.45
= 13.9794 + 195.268 + 32.45
= 241.697 dB
The FSPL in dB for a distance of 5Km and for the frequency of 5.8GHz is calculated as follows:
At, d=10 Km
FPSL (dB) = 20 log10 (10) + 20 log10 (5.8G) +32.45
= 20 + 195.268 + 32.45
= 247.718 dB
Below is a table summarizing the FPSL in dB for given distance of 5Km and 10Km for two
different frequencies 5.8GHZ, 2.4GHz
FSPL(dB)
Distance (Km) 2.4GHz 5.8GHZ
5 234.02 241.697
10 240.05 247.718
B.
For the information given below, calculate the link budget analysis for the wireless system,
which will involve calculating the following:
Received power
Link margin
Distance: 5Km
Frequency: 5.8GHz
Link type: point-to-point, line-of-sight
Tx power: +23dBm
Antenna gain: 24dBi
Assume negligible loss for cabling and connectors
Receiver sensitivity: -72dBm

It is being calculable that, if the received power is quite that of the link margin, the link budget is
claimed to be adequate enough to send the info underneath good conditions. (Quoracom. 2019)
Link margin is that the distinction between the received power and also the receiver sensitivity.
In alternative words, the number by that the received power exceeds the receiver sensitivity is
named the link margin.
Link budget analysis:
First, we want to calculate the received power. So as to calculate it, we want to grasp transmitter
power, the gain of the antenna and also the losses. And then, we've got to calculate the link
margin and are done by knowing received power together with the received sensitivity.
Formulae:
Received Power (dBm) = transmitted Power (dBm) + Gain (dB) – Losses (dB)
Gains (dB) = Transmit Antenna gain + Receiver Antenna Gain
The received power can be calculated as,
Received Power (dBm) = 23 +24–0 = 47 dBm
The link margin can be calculated as,
Link Margin = Received Power – Received Sensitivity
Link Margin = -47 – (-72) = 25 dBm
The link budget analysis for the wireless system is given by the formula,
Link budget = Received power – FPSL
Link budget can be calculated as follows,
Link Budget = 47 – 241.697
= -194.697 dBm
C.

For the calculated link margin at 5Km what can you say about the availability/reliability of the
link based on the following Table which shows the relationship between the available link
margin and link availability as a percentage of the time.
Time availability (Percentage) Link /Fade Margin
90 8
99 18
99.9 28
99.99 38
99.999 48
At now, we want to make sure that, the obtained link margin is enough for a reliable link. As per
calculation, we've got obtained the link margin of quite 20dB:
In order to calculate the link margin, we want to grasp, received power yet because the received
sensitivity. The obtained received power is 47dBm and also the given received sensitivity is
72dBm.(Ques10com.2019.)
The link margin are often calculated as,
Link Margin = Received Power – Received Sensitivity
Link Margin = -47 – (-72) =25dBm
The link margin looks to be adequate at 5km to transmit the
info and guarantee higher than 99% link availableness supported the
Rayleigh’s attenuation Model.
The obtained link margin is of 25dB. From the given table, it’s clear that our link margin lies
between the ranges of 18 to 28. and also the availableness of your
time in share might vary from 99 to 99.9.
References:
Idc-onlinecom. 2019. Idc-onlinecom. [Online]. [29 May 2019]. Available from: http://www.idc-
online.com/technical_references/pdfs/electronic_engineering/Free_Space_Loss.pdf

Quoracom. 2019. Quoracom. [Online]. [29 May 2019]. Available from:
https://www.quora.com/Why-is-the-received-power-negative-in-wireless-communication
Ques10com. 2019. Ques10com. [Online]. [29 May 2019]. Available from:
http://www.ques10.com/p/2681/explain-link-budget-analysis-and-requirements-of-1/
Researchgatenet. 2019. ResearchGate. [Online]. [29 May 2019]. Available from:
https://www.researchgate.net/publication/320465087_LINK_MARGIN_FOR_WIRELESS_RA
DIO_COMMUNICATION_LINK