# Design Considerations and Performance Evaluation of Gossi Routing in LoRa-Based Linear Networks
## 2 Related Work
The proposed multihop cooperation solution can be effective in terms of energy efficiency and network scalability [30]. A LoRa relay-based system has been introduced that uses multiple relays to establish communication in underground mining [31]. To ensure robust communications, a condition was proposed that time slots and node arrangements should be selected such that each node slot delay should not be equal to the sum of other slot delays [32]. However, by applying the proposed scheduling technique, the total introduced delay increases with the square of the number of nodes. Therefore, the traditional offset-based approach may not be equally effective, especially delay constraint applications [1; 32]. The flooding-based approach is regarded as the simplest way of propagating messages across a mesh network. In this method, whenever a node receives data packets, it forwards them to all neighbouring nodes, effectively selecting the fastest route without any complex routing overhead. However, as the network expands, this flooding-based approach leads to the creation of numerous duplicate packets, which in turn hinders performance in terms of energy consumption and introduces additional traffic to the network [33; 34]. Gossip routing is a modified version of the flooding-based approach. It uses a predefined random approach to send a packet, rather than simple broadcasting [35]. The gossip-based approach reduces the transmission overhead, which can further improve the message reachability in ad hoc networks [36]. Gossip routing is considered more-energy-efficient as compared to traditional flooding-based approaches [37]. A comparative study was conducted that measures the performance of various gossip routing approaches to estimate the network size [38]. A gossip-based approach can be highly effective in addressing both the dynamic loading problem and failure detection. Simulation results have demonstrated that the gossip-based approach reduces communication overhead by balancing the load at both local and global network levels [39]. Figure 2: An example of a chain-type wireless sensor network [20]. The gossip-based approach offers a way to enhance energy efficiency and optimise radio resource utilisation in comparison to the traditional flooding-based approach. In gossip routing, a message is forwarded with a probability less than one. Researchers have evaluated the feasibility of implementing gossip-based routing in wireless sensor networks, and the experimental results have demonstrated several advantages. The combination of gossip routing with flooding results in reduced power consumption, minimal traffic overhead, and improved network transmission delay [40; 41]. The integration of a gossip-based approach with different ad hoc routing protocols is highly beneficial in minimising unnecessary transmission overhead. Simulation studies have revealed that utilising the gossip-based approach can lead to a reduction of traffic overhead by up to 35% when compared to the flooding approach. However, the extent of transmission savings largely depends on the chosen gossip probability. Furthermore, the effectiveness of transmission savings is influenced by both the gossip probability and the specific design applications of the network, such as network-wide broadcast or point-to-point communication [42; 43]. The evaluation of LoRa technology with a gossip-based approach can be very effective as compared to conventional routing approaches, particularly within linear networks. Very little research has been carried out in this context. In this section, we highlighted some important contributions where LoRa has been proposed as a multi-hop technology. Mostly, authors have focused on relay synchronisation to avoid the contention issue. Introducing the slot time among different relay nodes can significantly solve the contention issue, but it also increases the communication delay. For larger networks with more relays, this problem becomes unmanageable; ideally, we need an alternate approach as the network scales.