## 4 Mobility Model of the MS
### Optimization Method
We justify the performance of CLR-MSPH by the efficiency of predicting and selecting the relay nodes to process the handover, even in the case where BMAC-H performs better than CLR-MSPH in terms of latency, the difference of latency is minimal as we saw in the previous test. ## 7 Conclusions

In this paper, we have studied the problem of continuous connectivity and delivering data during the data collection process by the MS. For this purpose, we have presented in this paper our proposed protocol called CLR-MSPH to deal with this problem. In order to show the performance of CLR-MSPH, we have performed simulations in different scenarios and compared the results with BMAC-H adapted to cluster-based wireless sensor networks. We see that in all studied scenarios the proposed CLR-MSPH performs better than BMAC-H in terms of packet reception rate, latency, and energy consumption. CLR-MSPH shows an efficient data collection even with the variation of the speed of the MS. CLR-MSPH performs in multi-hop communication (three hops) in order to route data to the MS with high packet reception rate compared to BMAC-H, which uses two hops. on the other hand, CLR-MSPH showed slightly less energy consumption than BMAC-H which proves that CLR-MSPH has an efficient energy awareness thanks to the cooperation between layers even with the multiple hop routing used by CLR-MSPH (three hops). In terms of latency (end-to-end delay), data packets are delivered with a shorter end-to-end delay using CLR-MSPH, especially with the scalability of networks. As future work, we have other considerations to extend this work in depth and face the limitations and open issues related to the handover mechanism in cluster-based wireless sensor networks. We plan to investigate the efficiency of the proposes protocol CLR-MSPH against other protocols based on

Figure 13: Energy consumption of both protocols in each topology. handover mechanisms such as RPL. We also plan to develop a mobility model for the MS that is adapted to the dynamic changes of network topology and CHs' positions. Besides, studying the adjustment of the mobile sink velocity according to the cluster heads' buffer size for a better data collection should also be considered in the mobility model of the MS. Finally, finding a suitable energy-aware clustering protocol taking into consideration the target coverage in order to organize the network in clusters and to minimize the number of the clusters, is considered one of the most important open issues that should be addressed. The first author [PERSON] proposed the idea, experiments, and methods. The work discussed and supervised by [PERSON], and he provided effective advices. The paper was written and structured mainly by [PERSON], and it revised and reviewed by [PERSON] and [PERSON]. This work was supported by Shenzhen Science & Technology Innovation Committee with Grant No. JCYJ20170306170559215 in Shenzhen China and Wuhan Science and Technology Bureau with Grant No. 20170102010105 in China. The authors declare no conflict of interest. ## References

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