## 4 Wireless Communication Technologies for IoT-Enabled Data Transmission
### Low Power Wide Area Networks
[96], who proposed a combination of RFID and Wi-Fi or cellular networks and used it in a supply chain for sweet melons from Brazil to Sweden to monitor temperature, RH, oxygen concentration, carbon dioxide concentration, and vibration or shock. They found that the dense packing of products inside the container lengthened the cooling time until the desired temperature was reached [96]. Furthermore, they measured critical CO\({}_{2}\) concentrations at different handling steps, which could have a negative effect on product quality [96]. [PERSON] et al. [97] developed and evaluated a monitoring system that uses RFID and cellular communication for tracking temperature, RH, vibration, O\({}_{2}\), CO\({}_{2}\), and ethylene in a fresh garlic scope supply chain. They were able to monitor the variability of these parameters during different supply chain steps [97]. Moreover, they state that the system enhanced the performance of the quality-relevant ambient parameters, resulting in a quality loss decrease from 20-30% to 15% [97]. The market price per kg of product increased by more than double. Still they discovered inefficiencies in their monitoring system that could be improved, for example regarding data quality, energy costs or adaptability to supply chain processes [97]. Some more examples of application studies are summarized in Table 2, together with an overview of the most important characteristics of the communication technologies as described above. \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Communication Technology** & **Characteristics** & **Studies Including Examples of Applications** & **References** \\ \hline
**NFC** & Low & \\ Costs & Low & Tracking of temperature information at different process steps (test was carried out in a meat supply chain, but concept is applicable to other products) & [82; 98; 99] \\ Power consumption & & \\ Transmission range & Standard ECMA-340, & \\ Frequency & ISO/IEC 18092 & \\ Standardization & Easy integration & \\ Additional aspects & (smartphone readable) & \\ \hline  & Low (passive/semi-passive tags) & Monitoring of temperature, RH, vibration, O\({}_{2}\), CO\({}_{2}\), ethylene in fresh garlic scope supply chain (in combination with cellular technology) & \\ RFID & Low (passive/semi-passive tags) & \\ Costs & tags/High (active tags) & Monitoring of temperature and RH in commercial fruit storage warehouses (in combination with ZigBee) & [82; 98; 99] \\ Power consumption & Unlicensed, 125-148 KHz (LF); 13.56 MHz (HP), 433 MHz, & Monitoring of temperature, RH, O\({}_{2}\), CO\({}_{2}\), vibration/shock in sweet melon supply chain (in combination with cellular technology or Wi-Fi) & \\  & & \\ Power consumption & Unlicensed, 125-148 KHz (LF); 13.56 MHz (HP), 433 MHz, & \\ Transmission range & 866-930 MHz (UHF), 2.45 GHz, & \\ Frequency & 5.8 GHz (Microwave) & \\ Standardization & Lack of uniform global standards & \\ Additional aspects & Readability problems for UHF & \\  & (e.g., metal, high water environment) & \\  & & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Overview of advantages, disadvantages and example applications of wireless communication technologies in the context of parameter monitoring in fresh fruit and vegetable supply chains.