## 3 IoT Standards and Protocols for Precision Agriculture
### IoT Protocols in Precision Agriculture (RQ2)
#### 3.2.3 Communication Between Non-IP and IP Protocols  
As of today, end-to-end LPWAN solutions are not widely available or always feasible, and they often requires working with multiple vendors to acquire nodes, gateways, backend servers, and other parts of the ecosystem separately. While this provides significant flexibility in applications, it places the burden on developers to implement the network by managing packetization, downlink control, multicast, and more. Low-Power Wide-Area Networks (LPWANs), such as LoRaWAN and SigFox, are a set of long-range communication technologies designed for IoT implementation. A low-power WAN creates a point-to-point connection between a device and a server. Many LPWAN applications and implementations are closely related to the underlying LPWAN technology [74]. As a result, entering new markets and integrating additional technologies often requires the time-consuming re-engineering of both the cloud and device applications. These emerging network technologies do not follow the IP-based Internet model [75]. They are not interoperable with each other and are difficult to integrate with existing architectures and information systems. Each IoT project typically involves first selecting a technology, then adjusting the choice of devices and platforms, and managing integration with the existing architecture. This has led the market to remain somewhat siloed by technology. In the Internet world, _interoperability_ and multiconnectivity are native properties. In fact, the Internet Protocol (IP) is open, allowing every user to operate around a universal reference standard. The Internet uses a layered model, where each layer implements a protocol and abstracts the complexity of the others. This hourglass model isolates the application from the network, saving significant design effort for every player in the value chain. At its core, IP provides optimized services such as addressing and routing, services that any application can inherit without needing to reimplement everything. For practical purposes, in this section, we will use LoRaWAN technology as an example to demonstrate how a non-IP protocol communicates with an IP-based protocol. Due to strict bandwidth limitations, LoRaWAN is unable to carry the heavy overhead of the IP protocol, so it implements the third layer of the OSI network model (Table 7), which is normally occupied by IP, in its own way [76]. Specifically, LoRaWAN handles the implementation of the second and third layers of the OSI network model (the data link and network layers). LoRaWAN's implementation of the third layer means that a LoRaWAN network cannot communicate with an IP network without the help of a gateway acting as a \"bridge\" between the two networks. LoRaWAN gateways are radio modules with a LoRa concentrator, allowing them to receive data packets. A LoRaWAN gateway is mainly used to transmit IoT device data to the cloud. The LoRaWAN technology itself is \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & **SigFox** & **NB-IoT** & **LoRaWAN** & **WiFi** & **Bluetooth** \\ \hline
**Standard** & SigFox & 3 GPP & LoRa Alliance & IEEE 802.11 & Bluetooth SIG \\ \hline
**Modulation** & BPSK & QSPK & CSS & DSSS, OFDM & GFSK \\ \hline
**Frequencies** & ISM: 433 MHz, 868 MHz, 915 MHz & Licensed under LTE & ISM: 433 MHz, 868 MHz, 915 MHz & ISM: 2.4 GHz, 5 GHz & 2.4 GHz \\ \hline
**Bandwidth** & 100 Hz & 200 kHz & 125 kHz, 250 kHz & 20 MHz, 40 MHz, 80 MHz, 160 MHz & 1 MHz \\ \hline
**Coverage** & 10–40 km & 2–20 km & 1–10 km & 10–100 m & 10–100 m \\ \hline
**Duty Cycle** & 144 packets/day & Unlimited & 1\% & Unlimited & Unlimited \\ \hline
**Max Data Rate** & 100 bps & 200 kbps & 50 kbps & Gbps & 2 Mbps \\ \hline
**Power Consumption** & Low & Low & Low & High & Low \\ \hline
**Security** & Low & High & High & Low-High & Low-High \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Comparison of IoT protocols [67; 73]. only used for communication between end devices and their connected gateways.