## 2 IoT Ecosystem Architecture for Smart Agriculture
### Communication Technology  
The survey of communication technologies for IoT [43; 44] indicated that to integrate IoT into the smart agriculture sector, communication technologies must progressively improve the evolution of IoT devices. They play an important role in the development of IoT systems. The existing communication solutions can be classified as: protocol, spectrum, and topology. Protocols: many wireless communication protocols have been proposed for the smart agriculture sector. Based on these protocols, devices in a smart agricultural system can interact, exchange information, and make decisions to monitor and control farming conditions and improve yields and production efficiency. The typical, low-power communication protocol numbers commonly used in smart agriculture can be divided into short-range and long-range categories based on the communication range. * Short-range: NFMI (near-field magnetic induction) [45], Bluetooth [46], ZigBee [47], terahertz (Z-Wave) [48; 49], and RFID [50]. * Long-range: LoRa [51], Sigfox [52], and NB-IoT (Narrowband IoT) [53]. Table 1 presents some typical communication technologies for the smart agriculture sector. The values in Table 1 indicate that short-range communication technologies have a transmission distance of less than 20 (m), high energy efficiency, and low data rate. These protocols are often employed in sensor networks, while long-range communication technologies have transmission distances of up to several tens of kilometres, consume more energy, and are installed for backhaul device-to-device communications. A diverse survey of low-power communication technologies for IoT that presents solutions, challenges, and some open issues is described by [PERSON] et al. [54]. Spectrum: Each radio device uses certain frequency bands for communication. The FCC (Federal Communications Commission) has defined unlicensed spectrum bands for unlicensed operations in scientific, industrial, and medical purposes [55]. These spectrum bands are often applied for low-power levels and short-range applications. Consequently, a series of common technologies for the smart agriculture sector, from wireless machine control and UAVs to communication technologies such as Wi-Fi and Bluetooth, use unlicensed \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Type** & **Spectrum** &
\begin{tabular}{c} **Transmission** \\ **Distance** \\ \end{tabular} & **Type of Network** & **Frequency** & **Data Rate** \\ \hline
802.11a/b/g/n/ac & Unlicensed & 100 m & WLAN & 2.4–5 GHz & 2–700 Mbps \\
802.11 ah & Unlicensed & 1000 m & WLAN & Several Sub-GHz & 78 Mbps \\
802.11p & Licensed & 1 km & WLAN & 5.9 GHz & 3–27 Mbps \\
802.11 af & Licensed & 1 km & WLAN & 54–790 & 25–550 Mbps \\ SigFox & Licensed & Rural: 50 km & LPWA & Zwave & 100–600 bps \\ LoRaWAN & Licensed & 20 km & LPWA & Several Sub-GHz & 0.3–100 kbps \\ NB-IoT & Licensed & 35 km & LPWA & Zwave & 250 kbps \\ LTE-3 GPP & Licensed & 5 km & WWAN & 1.4 MHz & 200 kbps \\ EC-GPRS & Licensed & 5 m & WWAN & GSM bands & 240 kbps \\ WHMAX & Hybrid & 50–80 km & WWAN & Several Sub-GHz & 70 Mbps \\ Bluetooth & Unlicensed & 100 m & WPAN & 2.4 GHz & 2–26 Mbps \\ ZigBee & Unlicensed & 1 km & WHAN & 2.4 GHz & 250 kbps \\ Z-Wave & Unlicensed & 100 m & WHAN & 900 MHz & 100 kbps \\
6 LoWPAN & Unlicensed & 30 m & WHAN & Zwave & 250 kbps \\ NFC & Unlicensed & 20 cm & D2D & 13.56 MHz & 424 kbps \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Some typical communication technologies for smart agriculture. spectrum bands [56]. However, the use of unlicensed spectra faces several challenges, such as the quality of service guarantee, the cost of setting up the initial infrastructure, and the interference generated by the huge number of IoT devices [57, 58]. A licensed spectrum usually is allocated to mobile networks. It provides more efficient network traffic, more reliability, enhances the quality of service (QoS), offers security, provides extensive coverage, and involves lower initialization infrastructure costs for users.