# Study of Mobility Enhancements for RPL in Convergecast Scenarios
## 4 The RSSI, Rank, and Dynamic+ (RRD+) Mechanism
### Loop Avoidance and Rank Update
In our future work, we plan to add a mechanism for RRD+ to distinguish static nodes from mobile nodes in order to improve the performance of RRD+ for different degrees of mobility. Moreover, energy consumption is another critical problem we need to investigate in the future. Right now we do not use sleep mode, since topology information updating relies on information broadcasting and collection in a timely manner and a sleep mode would delay this process. RPL is energy-efficient by design; compared to other mobility supports, RRD+ has lower overhead, and thus consumes less energy. Based on this, we plan to integrate a dynamic duty cycle in RRD+ according to different degrees of mobility in order to reduce energy consumption. In the long run, it is also interesting to improve RRD+ to support mobility in data dissemination scenarios. This research was conducted with the support of the European Regional Development Fund (FEDER) program of 2014-2020 and the Regional Council of Auvergne. **Author Contributions:** [PERSON] and [PERSON] conceived and designed the protocol and the simulation experiments; [PERSON] performed the simulation experiments; [PERSON] and [PERSON] analyzed the data; [PERSON] and [PERSON] wrote the paper. **Conflicts of Interest:** The authors declare no conflict of interest. Figure 2:0 Number of control packets. (**a**) Number of control packets (all nodes are mobile); (**b**) Number of control packets (75% of nodes are mobile); (**c**) Number of control packets (50% of nodes are mobile); (**d**) Number of control packets (25% of nodes are mobile). ## References

* [PERSON] (2011) [PERSON] _Multi-Sink Mobile Wireless Sensor Networks: Dissemination Protocols, Design and Evaluation_; University of Twente: Enschede, The Netherlands, 2011. * [PERSON] et al. (2014) [PERSON]; [PERSON]; [PERSON]; [PERSON] Wireless sensor networks: A survey on recent developments and potential synergies. _J. Supercomput._**2014**, _68_, 1-48. * [PERSON] and [PERSON] (2013) [PERSON]; [PERSON] A hospital healthcare monitoring system using wireless sensor networks. _J. Health Med. Inform._**2013**, \(4\), 121, doi:10.4172/2157-7420.1000121. * [PERSON] (2012) [PERSON] _RPL: IPv6 Routing Protocol for Low-Power and Lossy Networks_; Internet Engineering Task Force (IETF): Fremont, CA, USA, 2012. * [PERSON] and [PERSON] (2011) [PERSON]; [PERSON] _The Trickle Algorithm_; Internet Engineering Task Force (IETF): Fremont, CA, USA, 2011. * [PERSON] and [PERSON] (2016) [PERSON]; [PERSON] An efficient hand-off optimization based RPL routing protocol for optimal route selection in mobility enabled LLNs. In Proceedings of the 2016 International Conference on Global Trends in Signal Processing, Information Computing and Communication (ICGTSPICC), Jalgaon, India, 22-24 December 2016; pp. 130-137. * [PERSON] et al. (2016) [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON] An adaptive timer for RPL to handle mobility in wireless sensor networks. In Proceedings of the 2016 International Wireless Communications and Mobile Computing Conference (IWCMC), Paphos, Cyprus, 5-9 September 2016; pp. 678-683. * [PERSON] et al. (2016) [PERSON]; [PERSON], [PERSON]; [PERSON]; [PERSON] A modified RPL for Wireless Sensor Networks with Bayesian inference mobility prediction. In Proceedings of the 2016 International Wireless Communications and Mobile Computing Conference (IWCMC), Paphos, Cyprus, 5-9 September 2016; pp. 690-695. * [PERSON] et al. (2016) [PERSON]; [PERSON] [PERSON]; [PERSON], [PERSON]; [PERSON] A Bayesian model for mobility prediction in wireless sensor networks. In Proceedings of the International Conference on Performance Evaluation and Modeling in Wired and Wireless Networks (PEMWN), Paris, France, 22-25 November 2016; pp. 1-7. * [PERSON] et al. (2014) [PERSON]; [PERSON] [PERSON]; [PERSON]; [PERSON] [PERSON]; [PERSON]; [PERSON] Co-RPL: RPL routing for mobile low power wireless sensor networks using Corona mechanism. In Proceedings of the 2014 9 th IEEE International Symposium on Industrial Embedded Systems (SIES), Pisa, Italy, 18-20 June 2014; pp.