## 3 Methodology
### Choosing the Adequate Volume of Traffic in the LoRa Network  
The aim of analyzing the impact of the amount of transmitted network traffic within the network on the energy consumption for one-hop star topology scenarios is analyzed in [69], as quoted within this chapter. First, the scenario where all nodes send data at the same time interval, a typical case in rural scenarios for sending data collected from the field, is analyzed. It is concluded that node placement in a star topology presents a vital determinant of sensor node lifetime. However, although adequate signal coverage of the area must be achieved, the nodes should be as close as possible to the gateway to reduce energy consumption. Moreover, regarding the energy depletion of individual nodes, it is concluded that the star topology is more suitable for application to sensor networks than the cluster topology, in which the energy of cluster head (CH) nodes is depleted the fastest. Since CH nodes are difficult to replace, this causes the loss of functionality of the entire cluster, while in the star topology, the depletion of energy of an individual node does not cause such a loss in data delivery from the area it covers with its signal. In addition, it is concluded that in scenarios where sending a more considerable amount of data is unnecessary, as in the case of monitoring the state of yield, energy savings should be achieved by sending an adequately determined smaller volume of data from sensors. Finally, it is concluded that significantly less energy consumption can be noted within the same time interval when sending data with higher delay, i.e., less frequently. Thus, from the presented results, applying LoRa technology is an adequate solution in IoT scenarios where fast transmission of large amounts of data is not required, as in precision agriculture. In precision agriculture, additional energy savings can be achieved by sending smaller data sets over extended periods between transmissions. Considering these conclusions, optimizing energy consumption in a LoRa network requires consideration of the optimal packet size. To save energy, sending as little total traffic as possible is necessary. Therefore, optimizing packets to maximize information transfer in the minimum number of bits is vital [75]. Sending the highest value information, with the right balance of redundancy, compactness, and timeliness, should provide the best results in applying a sensor network based on LoRaWAN for monitoring environmental and agronomic data essential for precision agriculture. The LoRaWAN specification, defined for each worldwide region, provides for a maximum data payload size N. This maximum payload size varies by data rate (DR) because of the maximum on-air transmission time allowed for each regional specification. For example, for EU863-870, the maximum payload size for DR0-DR2 is 51 bytes, for DR3 it is 115 bytes, for DR4-DR7 it is 222 bytes, while for DR8-DR15 it is not defined [75]. If DR limits are restricted only to higher values, for instance, never below the chosen DR, this also limits how far away signals can be received, so this should be considered when choosing a packet length. Moreover, while 51 bytes in the payload in Europe may not be very restrictive, in the regions that operate in the 900 MHz ISM band, the lowest DR is restricted to 11 bytes [75]. However, for all DRs other than DR0, the available maximum packet size is equal to or greater than the EU863-870 region. Therefore, if the same packet format should be used in all regions, and DR0 is chosen to be supported (since a lower DR typically means a more extended range), the maximum payload length for any packet would be 11 bytes. If the sensor node is restricted to operate above the DR0, the maximum payload becomes 51 bytes. Since the sensors can monitor parameters related to both the environment and the state of the crops, the data in the packet payload is used to transmit measured values, for example, temperature, humidity, pressure, solar radiation, and rain.