Link Budget: Designing a High speed Wireless Data Link

This study material discusses the concept of link budget analysis for designing a high-speed wireless data link. It covers topics such as calculating free space path loss, determining the link budget, and analyzing the availability/reliability of the data link. The material provides formulas and equations to solve the given questions and includes references for further reading.

LINK BUDGET 0
Designing a High speed Wireless Data Link

LINK BUDGET 1
Table of Contents
Line of Sight link Budget analysis...........................................................................................................2
Question 1: calculate the free space path loss......................................................................................2
Question 2: Determine the link budget.................................................................................................3
Question 3: availability/reliability of the data link.................................................................................4
References.............................................................................................................................................6

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Line of Sight link Budget analysis
After analysing the given case study it has found that there are various kinds of key
factors which directly impact on the performance of a radio system. These factors
include availability, bandwidth, receiver sensitivity, antenna gains and atmosphere
condition (Elayan, et al., 2017). Therefore for solving the given questions there are
following formulas and equations will be used:
Question 1: calculate the free space path loss
After reviewing the case study it is identified that the value of FSPL is completely
depended on the major two factors for example distance and frequency (Erturk, and
Aksan, 2016). So, from the given question it is identified that the value of parameters
are given as:
Distances= 5KM and 10KM
Frequencies= 2.4GHz and 5.8GHz
Now, the value of free space loss can be determined with the below formula:
In which first we determine the value of FSPL at d=5KM and f= 2.4 GHz which is given
as
FSPL (dB) = 20*log10 (5) + 20*log10 (2.4*109) + 32.45

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So, FSPL(dB)= 114.03 dB
Similarly, at d= 10KM and f= 2.4GHz
FSPL (dB) = 20*log10 (10) + 20*log10 (2.4*109) + 32.45
And, FSPL (dB)= 120.05 dB
Therefore, at d= 5KM and f=5.8GHz
FSPL (dB)= 121.70 dB
Moreover, at d=10 KM and f= 5.8 GHz
FSPL (dB)= 127.72 dB.
All these values are indicated in the below table with free space losses on different
distance and frequency.
FSPL(
dB)
Distance (KM) 2.4GHz 5.8GHz
5 114.03 121.70
10 120.05 127.72
Question 2: Determine the link budget
In the given question the values of transmitter power, antenna gain, receiver sensitivity
and many more are given in order to find the link budget (Hussain, et al., 2015). Below
table shows these parameters along with the data:

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From the given case study, it is analysed that the link margin depends on the received
power so, it is very important to find the value of received power which is given below:
Put the value of transmitted power, gains and losses in the above formula in order to
determine the received power.
Received power (dBm) = 23 + 24*2 (both antennas are same)– losses (dB)
So, here the value of path loss can be determined with the above FSPL formula that is
Path loss= 20*log10 (5) + 20*log10 (5800) + 32.45= 121.70
Now, received power (dBm)= 23+48-121.70
Therefore, the value of received power is – 50.7dBm.
Or, link budget= -50.7dBm
Now, the value of the link margin can be calculated by using the below formula:
Put received power and received sensitivity for determining the amount of link margin
which is given as:
Link Margin= -(50.7)- (-72)
Link Margin= 21.3 dBm
Therefore, the value of link margin as per the given data is around 21.3dBm.

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Question 3: availability/reliability of the data link
From the above question, it is identified that at distance 5KM the value of link margin is
around 21.3dBm due to less transmission power and large path loss. The below table
indicates the relationship between the link or time availability and link margin.
After analysing this table it is identified that the availability of link depends on the
received power and link margin. Moreover, at 5KM the system more reliable because
the time availability is around 99% which shows that the system is reliable. So, it is very
important to reduce the value of path loss because it directly impact on the reliability of
the communication system (Wang, et al., 2017).

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References
Elayan, H., Shubair, R.M., Jornet, J.M. and Johari, P., (2017) Terahertz channel model and
link budget analysis for intrabody nanoscale communication. IEEE transactions on
nanobioscience, 16(6), pp.491-503.
Erturk, M.C. and Aksan, Y., (2016) A tool for beamforming and real-time link budget
analysis in aeronautical communications using kinematics. International Journal of
Aerospace Engineering, 12
(4), pp. 4-8.
Hussain, B., Li, X., Che, F., Yue, C.P. and Wu, L., (2015) Visible light communication
system design and link budget analysis. Journal of Lightwave Technology, 33(24),
pp.5201-5209.
Wang, Y., Bialkowski, K.S., Pretorius, A.J., Du Plooy, A.G. and Abbosh, A.M., (2017) In-
road microwave sensor for electronic vehicle identification and tracking: Link budget
analysis and antenna prototype. IEEE Transactions on Intelligent Transportation
Systems, 19(1), pp.123-128.