# Cluster-Based Data Aggregation in Flying Sensor Networks Enabled Internet of Things
## 4 Data Aggregation and Communication
### Data Aggregation Level 2 Algorithm
Figure 13 shows that, initially, the UAVs' data rate is 50 Kbps, and the packet drop ratio is very minimal. Still, with the increase in the UAVs' data rate, the packet drop ratio increases up to the highest level. The FSNet-OC-DA packet drop ratio is always lower when the data rate varies from 50 to 250 Kbps. Figure 14 represents the data rate and residual energy of UAVs. The residual energy decreases with the increase in the data rate of UAVs. The remaining residual energy of the FSNet-OC-DA is still better among other existing approaches. Figure 15 represents the UAVs' data rate and the ratio of the message overhead. The non-redundant data elimination approaches' communication overhead is higher than the proposed redundant data elimination schemes. Bandwidth is the capacity of communication channels among the UAVs. The bandwidth occupancy rate is the ratio of the

Figure 11: UAVs’ data rate vs. end-to-end delay. Figure 12: UAVs’ data rate vs. PDR. Figure 13: UAVs’ data rate vs. packet drop ratio. bandwidth used by the redundant data elimination aggregation approach and without redundant aggregation approaches. Figure 16 represents the bandwidth occupancy and redundancy rate of each UAV. The bandwidth occupancy of the FFNet-OC-DA is moving towards close to zero compared to the existing approaches. In FFNet-OC-DA, the UAVs avoid redundant data and transmit only actual data to a UAVS-CH. At the same time, the conventional data aggregation approaches utilize (50) percent bandwidth of the total available bandwidth. Figure 8:0 Redundancy rate vs. bandwidth occupancy. Figure 8:1 UAVs’ data rate vs. residual energy. Figure 8:2 UAVs’ data rate vs. message overhead. ## 6 Conclusions and Future Work

Sensors and UAVs have made it easier to monitor, observe, and share information about an area of interest remotely. The researchers proposed energy-efficient schemes by considering different parameters, such as reducing communication distance, computation cost, mobility, and degree. However, data collection minimizes the communication load to save bandwidth and energy. In this study, the honeybee foraging property was first used to select the optimal CH set and form stable and balanced clusters. The modified HBA selects UAVs-CH based on residual energy, UAV degree, and relative mobility. To transmit data, the UAV connects to the nearest CH. Ordinary UAVs choose CH randomly if they have the same distance with more than one CH. The reaffiliation rate will decrease with the proposed stable clustering procedure. Secondly, ordinary UAVs transmit data to their CH once clusters are formed. An aggregation method based on dynamic programming is proposed to save energy consumption and bandwidth. The data aggregation procedure is applied at the cluster level to minimize communication and save bandwidth and energy. Simulation experiments validate the proposed FSNet-OC-DA. FSNet-OC-DA is compared with non-redundant data elimination and aggregation approaches, such as EE-UAV-DA, OC-mUAV, and TA-UAV-DA, in terms of the end-to-end delay, PDR, packet drop ratio, residual energy, communication overhead, bandwidth occupancy with varying numbers of UAVs, data rate, and redundancy rate. The simulation results show that our proposed FSNet-OC-DA outperforms state-of-the-art cluster-based data aggregation schemes. Conceptualization, M.A. ; methodology A.S. and Q.J. ; software, A.S. and I.W. ; validation, A.S. and M.Y.A. ; draft preparation, A.S., M.Y.A. and I.W. ; review and editing, M.A. and I.W. ; visualization, A.S.; supervision, Q.J. ; funding acquisition, M.Y.A. All authors have read and agreed to the published version of the manuscript. This research received no external funding. Data Availability Statement: Data will be made available on request. The authors wish to thank the editor and anonymous referees for their helpful comments on improving the quality of this paper. The authors declare that we have no conflict of interest regarding the publication of this article. ## References

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