# Fuzzy-Logic Dijkstra-Based Energy-Efficient Algorithm for Data Transmission in WSNs
## 5 Performance Evaluation
### Results and Discussions  
Figure 6a,b compares the network system lifetime of four routing schemes. When the number of rounds reaches 100, the gap among the algorithms for the number of dead nodes begins to be seen clearly. It can be noted that SPFL shows a drastic increase compared to other algorithms. It is owing to the fact that the PM located near the source node selects the next hop node to be the one with minimum distance from itself. This selection is done regardless of the energy level of the selected relay node, which results in the early death of nearby nodes. Additionally, before the selection of the shortest path from the source to the destination node, the PM asks all the nodes in the network to send their information; this can cause unnecessary energy consumption of the nodes located far away from the PM. It can be seen that ESRAD and FML show a constantly increasing trend in terms of the number of dead nodes in the network. In the proposed scheme, the fuzzy membership function considers the residual energy of the neighbor nodes instead of the source node, as seen in FML and ESRAD. Moreover, the intra-cluster communication cost function selects a node located at the minimum distance to the CH among the neighbor nodes, which resulted in the even assignment of the data relaying tasks to each capable node. This behavior of the weight function encourages the energy conservation of the nodes and results in better performance compared to the other three algorithms. According to the results in Figure 6a, the data for certain specific number of rounds was extracted when some of the nodes died, and the percentage of the node death after each interval was plotted to visualize the performance comparison of the four algorithms more intuitively. It is evident from the results in Figure 6b that at round number 300, the percentage of dead nodes was almost 50 in SPFL, 30 in FML, 25 in ESRAD, and 20 in the proposed scheme. The comparison of performance of the existing algorithms with the proposed scheme reveals that the proposed scheme performs better owing to the consideration of the residual energies of neighbor nodes. Figure 7a illustrates the comparison of the network energy conservation of the four routing schemes. The proposed scheme outperforms the other three routing algorithms owing to the consideration of the residual energy of the relay nodes. Additionally, selection of the node that offers minimum intra-cluster communication cost avoids the inclusion of the intermediate nodes that are located far from the CH, and therefore, saves the nodes from unnecessary depletion of energy owing to the longer distance as seen for FML and ESRAD. It is evident that SPFL has the lowest energy conservation and highest energy consumption because the PM proposes multi-hop path from the source to the destination node on the basis of shortest distance regardless of the energy of the intermediate nodes. Once the relay nodes located near the PM depleted their energies beyond a threshold level, the nodes positioned far away were being selected; this consumed extra power and resulted in minimum conservation of  
Figure 6: Performance comparison of network lifetime of the four algorithms: (a) number of dead nodes with respect to number of rounds; (b) percentage of dead nodes corresponding to specific number of rounds. energy. Figure 7 presents the comparison of network energy consumption with respect to increasing number of nodes in the network. It can be observed from the graph that when network size is increased from 100 nodes to 500 nodes, the difference between the amounts of energy consumption for FML, ESRAD and proposed scheme is about 0.01 J whereas SPFL shows energy consumption of 0.1 J which is 1% of node's total initial energy. This is because when a shortest path is required between a source and destination node, all the nodes send their information to the central PM node which results in unnecessary energy consumption within the network.