# Performance Evaluation of a Mesh-Topology LoRa Network
## 7 Results
### Power Consumption Comparison  
To compare the power consumption of LoRaMesh directly to LoRaWAN, a single example scenario has been set up to demonstrate the differences. The example parameters have been chosen to specifically highlight the advantages of LoRaMesh; however, this does represent typical network deployments. In the example scenario, 260 devices are randomly distributed around a single gateway within a radius of 6.5 km, and 10-byte up-link data transmissions are scheduled every 600 s. We have chosen a 10-byte data packet as it is representative of the typical requirements of an IoT sensor such as an air quality sensor, soil moisture sensor, or latitude and longitude GPS location. The network radius is chosen to force the use of all the different \(SFs\) available to the LoRaWAN devices. The power consumption includes the transmission, receive, standby, and relay (in the case of the LoRa mesh network). Figure 8 highlights the inherent problem of multi-hop networks. The nodes located in the first hop from the GW exhibit the highest energy consumption due to the node's increased time spent in reception mode to aggregate child packages and re-transmitting the packages. When comparing the results of Figure 8 vs. the results in Figure 9, the advantages and disadvantages of a mesh-based network become apparent. Nodes located further than 5 km from the GW will, on average, have a reduction in power consumption in a mesh-based network compared to a LoRaWAN-based network. This is an advantage  
Figure 7: PDR of a multi-hop network with different numbers of nodes placed within a 3.927 km, 5 km, and 7.071 km radius of the GW, normalised to node density. for energy constraint devices, which have a high attenuation to a centralised gateway. This higher attenuation is typically due to devices being placed in adverse locations where maintenance on the devices is difficult. However, relay nodes which are closer to the central GW have significantly higher power consumption. The results and advantages of such a network will be highly dependent on the targeted application. In Section 5.5, the \(E_{Tot}\) per up-link cycle was calculated as 0.097136 J, which was calculated for an identical test case to that which is represented in Figure 9. The \(E_{Tot}\) can be calculated as 0.097136 J for 10 consecutive up-link cycles, which matches the simulated results in Figure 9 for devices transmitting with SF11. Table 2 summarises the energy consumption measurements of the relay nodes in the simulation results depicted in Figure 8. The percentage difference in power consumption of nodes utilising the same spreading factor with varying number of child nodes highlights the additional energy consumption of these relay nodes. Although the relay nodes need to relay the data packets, the energy consumption is not increased linearly, as the energy used in standby and during synchronisation is not scaled. The large delta increase in power consumption between SF7 nodes not relaying any packet and SF7 nodes relaying a single packet is due to the average power consumption of nodes close to the gateway being extraordinarily low due to a high data rate and low transmission power. To provide a more comprehensive average power consumption comparison of a single-hop network vs. multi-hop network, we simulated a varying amount of nodes in both single-hop and multi-hop networks. The nodes are randomly distributed around a single gateway, within a 6.5 km radius; 10-byte data transmissions are scheduled every 600 s for a total of 10 transmissions. The network radius is once again chosen to force the use of all the different \(SFs\) available to the LoRaWAN devices. Figure 8: Energy consumption of a multi-hop network vs. distance from the GW. Figure 9: Power consumption of a LoRaWAN with ADR vs. distance from the GW. Figure 10 summarises the average power consumption of the devices for three different distances from the gateway.