Wireless Communication

This article discusses the selection of a suitable frequency band for WSN, calculation of channel capacity, noise levels, signal power, and more. It also suggests functionalities for cloud applications to effectively use sensor data and how IoT platforms can help the implementation of WSN.

Wireless Communication
Name:
Professor:
Date:

a. Select a suitable frequency band for WSN and give reasons for your selection.
Answer:
The best frequency band selected for WSN is LoRaWAN frequency band (Australia
915-928 MHz). This is because this frequency is unlicensed radio spectrum. That means
we will not incur the cost of paying for the frequency band.
b. Calculate the channel capacity (minimum data rate) required for:
I. One sensing device to control center channel.
Answer:
Minimum bit rate=bandwidth∗log2 (1+ SNR )=13∗106∗log2 (1+19 )=56185065.23 bps
II. Control center to ISP channel.
Answer:
Minimum bit rate=n∗bandwidth∗log2 ( 1+ SNR )=2500∗13∗106∗log2 ( 1+19 )=1405 Gbps
c. c) For both the channel types calculate the following noise levels experienced:
I. Thermal noise.
Answer:
thermal noise= √ 4 RKfT = √ 4∗1.38∗10−23∗( 20+273 )∗13∗106∗8∗103 =41.01 μV
II. Total noise experienced
Answer:
total noise= 100
5 ∗41.01∗10−6 =82.03 μV
d. It is expected to maintain SNR of 63 at the control center for sensor signals.
i. Calculate the signal power received at control center from one sensing device.
Answer:

Prx =Ptx Gtx Grx ( c
4 πDf )2
=1∗10∗100∗
( 3∗108
4∗3.142∗1500∗13∗106 )2
=0.01499 watts
ii. Calculate the bandwidth of the sensing device to control center channel.
Answer:
Bandwidth=n*bandwidth of a single sensing device=2500*5=12500bps.
iii. What will be the bandwidth of the multiplexed channel if FDM scheme is used?
Answer:
bandwidth=2500∗13∗106=32.5 Ghz
e. Calculate the maximum free space loss experienced by the signals sent from sensors.
(Assume control Centre is located exactly at the center of the landscape)
Answer:
FSPL=20 log ( d ) +20 log ( f ) +20 log ( 4 π
c )−¿−Gr
¿ 20 log ( 1500 ) +20 log ( 13∗106 ) +20 log ( 4 π
3∗108 )−10−100=¿−51.76 dB ¿
f. Determine the required transmission signal strength if other impairments such as
attenuation and fading causes loss of 30% in signal power during the propagation from
sensors to the control Centre.
Answer:
transmission signal strength=output power +losses−antenna gain=¿63dBm+51.76dBm-
10.5dBm=104.26dBm
g. With your general knowledge in agriculture sector and business suggest functionalities
for the cloud application to effectively use sensor data.
Answer:

Weather and climate prediction from the temperature and humidity data collected.
Goods and services flow in business and also demand and supply distribution in the
economy.
h. Suggest how IoT platforms can help the implementation of WSN. (Research in google to
find answer for this)
Answer:
Sensors and actuators embedded in physical objects from roadways to pacemakers are
linked through wired and wireless networks, i.e using same IP protocal that connects the
internet. These will facilitate huge transmission of volumes of data flow for computer
analysis hence help in implementation of WSN.
References

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