Iot-based Smart Irrigation Systems: An

Figure 24. Most utilized processors to implement IoT nodes for irrigation systems.

2. 
   Communication Technologies
   

In this subsection, an overview of the most employed wireless communication technologies is going to be presented as well.
According to the Machina research report, the number of connected agricultural devices is expected to grow from 13 million at the end of 2014 to 225 million by 2024 [183]. In addition, the report predicts that around half of those connections will use the newly emerging low power wide area network technologies which are particularly well suited to many of the applications in agriculture.
When IoT devices are implemented, the employed communication technologies are a key point to achieve successful operation. In a generic way, communication technologies can be classified according to the environment where they will be deployed, the utilized communication standard or the utilized spectrum band. Table 5 shows the main technologies used in IoT for irrigation systems.

Table 5. Main technologies used in IoT for irrigation systems.

Group Technology Frequency Bands Max. Data Rate
380.2–389.8 MHz, 390.2–399.8 MHz, 410.2–419.8 MHz, 420.2–429.8 MHz,
450.6–457.6 MHz, 460.6–467.6 MHz, 479.0–486.0 MHz, 489.0–496.0 MHz,

Cellular

3G

4G/LTE
5G

698.2–716.2 MHz, 728.2–746.2 MHz, 777.2–792.2 MHz, 747.2–762.2 MHz,
806.2–821.2 MHz, 851.2–866.2 MHz, 824.2–848.8 MHz, 869.2–893.8 MHz,
890.0–915.0 MHz, 935.0–960.0 MHz, 880.0–915.0 MHz, 925.0–960.0 MHz,
876.0–915.0 MHz, 921.0–960.0 MHz, 870.4–876.0 MHz, 915.4–921.0 MHz,
1710.2–1784.8 MHz, 1805.2–1879.8 MHz, 1850.2–1909.8 MHz, 1930.2–1989.8 MHz
452.5–457.5 MHz, 462.5–467.5 MHz, 703–748 MHz, 703–803 MHz, 704–716 MHz,
717–728 MHz, 734–746 MHz, 738–758 MHz, 758–803 MHz, 791–821 MHz,
807–824 MHz, 814–849 MHz, 815–830 MHz, 824–849 MHz, 830–845 MHz,
832–862 MHz, 852–869 MHz, 859–894 MHz, 860–875 MHz, 869–894 MHz,
875–890 MHz, 880–915 MHz, 925–960 MHz, 1427.9–1447.9 MHz,
1475.9–1495.9 MHz, 1447–1467 MHz, 1447.9–1462.9 MHz, 1495.9–1510.9 MHz,
1525–1559 MHz, 1626.5–1660.5 MHz, 1710–1770 MHz, 1710–1755 MHz,
1710–1780 MHz, 1710–1785 MHz, 1749.9–1784.9 MHz, 1805–1880 MHz,
1844.9–1879.9 MHz, 1850–1910 MHz, 1850–1915 MHz, 1880–1920 MHz,
1910–1930 MHz, 1930–1990 MHz, 1930–1995 MHz, 1920–1980 MHz,
1920–2010 MHz, 2000–2020 MHz, 2010–2025 MHz, 2110–2155 MHz,
2110–2170 MHz, 2180–2200 MHz, 2300–2400 MHz, 2305–2315 MHz,
2350–2360 MHz, 2496–2690 MHz, 2500–2570 MHz, 2620–2690 MHz, 3400–3600
MHz, 3410–3490 MHz, 3510–3590 MHz, 3600–3800 MHz, 5150–5925 MHz
Frequency Range 1: 663–698 MHz, 617–652 MHz, 699–716 MHz, 703–748 MHz,
717–728 MHz, 729–746 MHz, 758–803 MHz,788–798 MHz, 758–768 MHz,
791–821 MHz, 815–830 MHz, 824–849 MHz, 832–862 MHz, 860–875 MHz,
869–894 MHz, 880–915 MHz, 925–960 MHz, 1427–1432 MHz, 1427–1470 MHz,
1432–1517 MHz, 1475–1518 MHz, 1695–1710 MHz, 1710–1780 MHz,
1710–1785 MHz, 1805–1880 MHz, 1850–1910 MHz, 1850–1915 MHz,
1880–1920 MHz, 1920–1980 MHz, 1920–2010 MHz, 1930–1990 MHz,
1930–1995 MHz,1995–2020 MHz, 2010–2025 MHz, 2110–2170 MHz,
2110–2200 MHz, 2300–2400 MHz, 2305–2315 MHz, 2350–2360 MHz,
2496–2690 MHz, 2500–2570 MHz, 2570–2620 MHz, 2620–2690 MHz,
3300–4200 MHz, 3300–3800 MHz, 3550–3700 MHz, 4400–5000 MHz
Frequency Range 2: 26.50–29.50 GHz, 24.25–27.50 GHz, 37.00–40.00 GHz,
27.50–28.35 GHz
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