# An Efficient Mobility Model for Improving Transmissions in Multi-UAVs Enabled WSNs
## 3 Literature Review
The smell index is used to fix the initial length of the congestion window and a smell probabilistic model takes care of increase or decrease of the window size. A route rehabilitation procedure is employed because there a certain violation that is inevitable and the network demands recovery. The concluding remark on the protocol is that it provides an efficient routing mechanism and congestion avoidance when routing between two different kinds of networks ([PERSON] et al., 2018). A demand-based UAV placement model is discussed in ([PERSON] et al., 2018), which employs a neural-based cost model to estimate the zones where UAV is placed. The model is driven by the principle of demand patterns, which, in turn, assign cast and density to separate areas and UAVs. A neural-based model that applies multiple UAVs instead of a huge amount of small cells provides a less complex and more efficient load balanced system. A huge application of small cells is also not cost effective. UAVs, when used as flying access points, can provide reliable connectivity to failure-prone areas. However, above all, a very fine and efficient approach is mandatory for UAV topology formation and coverage issues. The proposed model that is driven by density and cost functions that compute areas with high demands and UAVs are deployed based on these metrics. The target is not only to find efficient positioning but also the altitude, as high altitude is more resilient to interference but involves additional delays. Test results demonstrate that the efficiency increases by one third if UAVs are employed instead of small cells. A multi-objective genetic algorithm with objectives' delivery hit rate, delivery cost, and delivery latency, respectively, for data dissemination in delay tolerant UAV networks is presented in ([PERSON] et al., 2018). Delay Tolerant Networks (DTNs) prove to be very useful in disaster scenarios, intelligent transport systems, wireless sensor networks, etc. A probabilistic cut node based forwarding scheme for delay tolerant UAV networks is presented in ([PERSON] et al., 2018). The cut nodes belong to two different networks if the network is viewed as a disconnected graph. Jaccard distance is used to measure the dissimilarity between the nodes so as to judge which nodes belong to the same social network and still have an outside connection. A traveling salesman based smooth path construction mechanism was proposed in ([PERSON] et al., 2018). A three-dimensional UAV rotational and polarization model is presented in ([PERSON] et al., 2018). [PERSON] et al. (2018); [PERSON] et al. (2018) proposed a heuristic based adaptive scheme for UAV deployment. A Delaunay triangulation mechanism is used to increase connectivity and the changing topology is monitored constantly in order to adapt to the inevitable dynamic topology. Another adaptive algorithm for filtering UAV movements using Kalman Filters is presented in ([PERSON] et al., 2018). UAV deployment and movement models are also considered in ([PERSON] et al., 2018; [PERSON] et al., 2018; [PERSON] et al., 2018).