# Design Considerations and Performance Evaluation of Gossi Routing in LoRa-Based Linear Networks
## 4 Experimental Setup
### Network Design and Configuration  
We conducted four sets of experiments with different numbers of relay nodes at each station. The number of co-located relay nodes represented the 'width' of the network. In the first set of trials, we only used a single node at each station. The network formation along with ideal coverage estimation is shown in Figure 5. In the second and third trials, we added the additional relay nodes at each station to increase the thickness of the LoRa-based linear network. However, the additional relay nodes at each station can be added in two ways, either collocated or using a physical offset between relay nodes. Collocated nodes are placed adjacent with approximately zero distance between two nodes, whereas the physical offset between relay nodes can be achieved via moving the relay nodes along the x-axis or y-axis. In the second trial, we added an additional relay node at each hop. The network architectural designs with a relay width of two nodes considering both cases are shown in Figures 6 and 7, respectively. Figure 4: Aerial view of network deployment (source: Google maps). Figure 5: Network architecture using a single relay node at each hop with ideal coverage estimation. In the third experimental trial, we further increased the width of the LoRa-based linear network by introducing another additional relay node at each hop. We considered both cases of collocated and a physical offset between relay nodes. The network architectural designs with a relay width of three nodes considering both cases are shown in Figures 8 and 9, respectively. During the experimental trials (1, 2, 3), at least 500 packets were sent from the source to the destination via the relay nodes. We used the same configuration throughout the experiments (please see Table 1). The selection of the LoRa transmission parameters can play an important role in ensuring efficient and reliable communication. LoRa technology provides different configurable settings such as the spreading factor, bandwidth, coding rate, and transmission power to optimise the performance depending on the application use cases. The adoption of a higher SF increases the LoRa signal quality with an improved SNR value at the costof air time. Employing the higher bandwidth helps to increase the data rate, but it also lowers the receiver sensitivity because the utilisation of a wider band  
Figure 8: Network architecture of collocated relay nodes of a width of three with ideal coverage estimation. Figure 6: Network architecture of collocated relay nodes of a width of two with ideal coverage estimation. Figure 7: Network architecture of physically offset relay nodes of a width of two with ideal coverage estimation. Figure 9: Network architecture of physically offset relay nodes of a width of three with ideal coverage estimation. allows the integration of additional noise. Lower coding rates can offer more resilience in the presence of interference, but also increase the time on air because of the additional redundant bits. The use of higher Transmission Power (TP) can slightly improve the RSSI (up to 2 to 3 dBm) by changing the transmission power to 11 dBm, 17 dBm, and 23 dBm, respectively. The usage of higher transmission power significantly increases the power consumption in LoRa-based networks, which also depends on the hardware. However, it is very challenging to evaluate the performance against each configurable parameter (6720 possible settings) [45; 46]. In the fourth experimental trial, we explored the gossip-based approach with two and three active relay nodes using the one-hop model. Gossip routing is often regarded as the preferred solution, particularly in decentralised and resource-limited environments. Within such networks, nodes possess the capability to communicate directly, eliminating the need for a centralised mechanism to disseminate information. The adoption of a gossip-based approach ensures the resilience required to establish reliable communication under challenging network conditions.