# Context-Aware Gossip-Based Protocol for Internet of Things Applications
## 2 Related Work
The selection of the next node in FELGossiping is based on its residual energy and distance to the sink. In FELGossiping, when a node detects an event and wants to send information, it determines its next hop based on its neighbouring nodes' residual energy levels and hop counts. This procedure continues until the message reaches the sink. Thus, it effectively increases the energy available to the network and maximises its lifetime. The performance of the proposed protocol was compared with the performances of three other algorithms, namely, the original gossiping protocol, LGossiping [21], and ELGossiping [22], in terms of the packet loss, number of live nodes, energy consumption, and delay. FELGossiping outperformed the other protocols by achieving a high packet delivery ratio, reduced delays, a fair energy balance among nodes, and an increased node lifetime. Nevertheless, FELGossiping uses hop counts for distance measurement; however, it is very loosely correlated with the distances as it represents the number of intermediate nodes in which data pass between the source and destination nodes. Fuzzy-Gossip is a modified gossiping protocol that uses fuzzy logic to reduce the energy waste caused by recirculation redundancies, thus improving the network lifetime [24]. The proposed protocol determines the next node from among a set of candidate nodes by favouring nodes with the highest remaining energy levels and the shortest distances to the sink. This is made possible through the use of fuzzy logic to determine a selection cost for each candidate node based on a series of five membership functions. The effectiveness of Fuzzy-Gossip in comparison with three other protocols, i.e., the original gossiping protocol, LGossiping [21], and ELGossiping [22], was demonstrated through simulations. Compared with these protocols, Fuzzy-Gossip was found to reduce message routing redundancy and balance energy consumption more effectively while also maximising the network lifetime. However, this protocol is arguably unscalable because the computational overhead due to the processing of the fuzzified values can lead to high energy consumption. A probabilistic approach is adopted in a new variant of the gossiping protocol, Gossiping-PS, which introduces new mechanisms for the selection of the next node based on a probability function [25]. The motivation for this proposal was to reduce the routing delay and improve the network lifetime. The probability function is inspired by the ant colony function [26] and determines the node to be selected based on two factors: the residual energy of the node and its visibility [27]. The node with the highest probability, i.e., a node with a high level of energy and a close distance to the sink, will thus be selected as the next hop for routing. The performance of Gossiping-PS was compared with that of the simple gossiping protocol in terms of the response time, network lifetime, and residual energy. The findings showed that the Gossiping-PS protocol reduces the response time and prolongs the network lifetime in comparison with those achieved with the original gossiping protocol. Nonetheless, the probability function that combines both the residual energy of the node and its visibility was not mentioned in the study. An energy-efficient variant of the gossiping protocol was proposed based on fuzzy logic and Chebyshev distances [28]. In this approach, a distance-based scheme is adopted to determine the path of a message from its source to its destination by favouring nodes with the most residual energy and the shortest distances to the sink. The performance of this new routing algorithm was compared against those of the traditional flooding and gossiping protocols in terms of the energy consumption, hop count, and network lifetime. The results showed that the new protocol enhances the performance of a WSN and increases its lifespan.