## 5 Discussion
\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
**ZigBee** & Low & Monitoring of temperature and RH in commercial fruit storage warehouses (in combination with RFID) & [13; 81; 83; 90; 95] \\ Frequency & 2.4 GHz & Monitoring of temperature, RH and vibration during truck transport of lettuce & [13; 81; 83; 90; 95] \\ Standardization & Standard 802.15.4 & & \\ \hline
**Bluetooth** & Low & Monitoring of temperature, RH and CO2 concentration in storage of oranges (in combination with Wi-Fi) & [81; 83; 104; 105] \\ Frequency & Standard 802.15.1 & Monitoring of ascorbic acid content in fresh parsley & \\ Standardization & Easy integration & fresh parsley & \\ Additional aspects & (smartphone readable) & & \\ \hline
**Wi-Fi** & Low & & \\ Costs & High (if sensors are connected directly to Wi-Fi) & Monitoring of temperature, RH, O2, CO2 concentration & \\ Power consumption & Short (up to 100 m) & vibration/shock in sweet melon supply chain (in combination with RFID) & [81; 83; 96; 106] \\ Transmission range & Unlicensed, 2.4 GHz & Monitoring of temperature during land transportation of iceberg lettuce & \\ Standardization & Standard IEEE 802.11 & Monitoring of temperature, RH and CO2 concentration in a simulated peaches and nectare supply chain (in combination with RFID) & \\ Additional aspects & (smartphone compatible) & & \\ \hline  & High (if sensors are connected directly to cellular communication) & Monitoring of temperature, RH, O2, CO2 concentration & \\ Costs & Long (several km) & Vibration/shock in sweet melon supply chain (in combination with RFID) & \\ Power consumption & Licensed, 1.7-2.7 GHz (2G/3G/4G) & chain (in combination with RFID) & [80; 81; 83; 96; 97; 103; 107; 109] \\ Frequency & Different standards, depending on technology & Monitoring of temperature in kiwifruit supply chain (in combination with RFID) & \\ Additional aspects & Large coverage & Monitoring of temperature, RH and CO2 concentration in a simulated peaches and nectare supply chain (in combination with RFID) & \\  & Easy integration & & \\  & (smartphone compatible) & & \\ \hline  & Low (operation in unlicensed spectrum) & & \\ LPWAN & High (operation in licensed spectrum) & & \\ Costs & Low & Monitoring of temperature RH in tomato greenhouses (LoRa in combination with Wi-Fi) & \\ Power consumption & Long (several km) & with Wi-Fi & \\ Transmission range & Unlicensed and Licensed, depending on technology & Monitoring of temperature, RH and CO2 concentration in tomato greenhouse (LoRa) & \\ Additional aspects & Different standards, depending on technology & & \\  & Coverage in suburban and rural areas might be incomplete & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: \(Cont.\)and controlled for achieving added value. Nevertheless, certain commonalities can be identified. Quality loss and spoilage in fruit and vegetables are mainly driven by respiration, transpiration, microbial decay, degradation of components and mechanical damage or injury. Categorizations of products with similar storage requirements or ethylene sensitivity are developed to facilitate multi-commodity transport and storage [115; 116; 115]. Clustering approaches can deliver an important contribution to establish which ambient parameters are most important to monitor for which products. The complexity in choosing the relevant ambient parameters for each product is further increased by a vast range of options for IoT technologies. Regarding the device layer, sensor development is advanced, especially for monitoring of temperature and RH. Ready-to-use devices or modules for prototype customization are cost-efficient and commercially available on large scale. For the network layer, a variety of communication technologies is available that offer fast and simple data transmission.