Wireless Sensor Networks in Precision Agriculture for Improved Crop Production

WSN Frequency Band
Now a days, precision crop management in agriculture is widely used in association with
information technology to improve quality and quantity of production.An example of such
technology is Wireless Sensor Networks(WSN) that are used by farmers in agriculture to provide
large amount of information like sound, pressure, pollution level, humidity, temperature, wind
etc. that are helpful in good crop production. Using these Wireless sensors wide area of farm can
be monitored easily as they consists of network of sensor nodes that are distributed spatially.
These sensors collect and process all the data like information regarding physical conditions of
an environment, preventing wastage of pesticides, providing appropriate quantity of nutrients for
crops etc. centrally. These wireless sensor networks contains various sensors, processors , RF
modules that are all battery powered.Today these networks are used in all fields of society like
sport, industry , medicine but in agriculture it is the most favorable and cost effective activity to
improve crop production yield and help farmers.
As in this case study, farm chosen is 3 km by 3 km which is too wide area in such case Long
range radio (LoRa) wireless protocol is used that uses long range radio frequency band i.e. 433,
868, 915 Mhz ISM bands. It consume less power, small size, easy implantation of networks,
scalability, low latency and can be easily deployed in vast agriculture field. In this LoRa uses star
topology in which all the data from nodes are collected and communicated using cloud server
over long distance with high scalability. It was used for improving Corn production in Italy by
improving fertilization methods (Jawad et al., 2017).
The channel capacity calculation
Channel capacity means the upper bound on the rate at which information can be
transmitted over channel. The capacity of channel can be increased by reducing the transmission
power used by wireless sensor networks. The MIMO antenna are used to increase the capacity of
channels of wireless sensors networks. In this method efficient space time is provided.
Formula to compute bit rate:

I ) Centre channel controlled by one sensing device
In this case the channel capacity of centre channel is 100 bits/s which is controlled by one
sensing device.
II) Control centre to ISP channel
For ISP the channel capacity is 90 bits/s which is controlled by centre.
Noise -level calculations
I ) Thermal Noise
Thermal noise is also called as white noise. Thermal noise power is directly proportional to
bandwidth. It spread over spectrum.
Temperature = 20 degree Celsius
Resistance = 10 Ohms
Bandwidth = 10 Hz
Result
Noise Voltage = 0.00127238 microvolt RMS
Noise power = -163.9 dBm
II) Total Noise
Total noise calculations depend on the thermal noise.As it is given only 5% of total noise
experienced is thermal noise in wireless sensor networks (Adelantado et al., 2017).