## 2 Literature Review
The scheme outperforms the counterpart schemes in network throughput and latency and consumes high energy. In [19], the authors propose a scheme to save the energy and enhance the network throughput. For this purpose, four movable sinks are considered which move according to the sender node position. The movement of the sink is considered only for the horizontal axis, which decreases the latency due to the sink movement. When the sink stays for a specific interval of time, nodes nearest to that sink, forward their information. The best forwarder nodes (destination and relay node) are selected by calculating the distance regarding the movable sink node. If any sink node is available in the sender broadcasting range, then nodes forward their information towards it. However, if the sink is not available in the sender field then cooperation performs. This approach outperforms in terms of network energy consumption. However, it blindly selects the channel link for transmission data which effects the PDR. The Table 1 shows the technique used, accomplishment and deficiency of the delay sensitivity schemes. In [20], the source node chooses the best forwarder node using its depth and nodes present in its vicinity. Further more, a depth threshold is applied to select the relay node. Path set up is established through a calculated metric to reduce the latency, which considers the source node with a reference from the sink node. The proposed approach improves the scheme in [12] in which the source node forwards the information to the nodes which have best links for data advancement. The proposedalgorithm renders good network throughput and engrosses small amount of energy at the cost of compromised reliability. In [21], the authors present a new cooperative fashion routing algorithm to reduce the channel effects. The whole network is divided into three equal zones to balance the energy consumption. The source node broadcasts a hello bag, the information of node ID, residual energy and signal to noise ratio (SNR) of all neighbor nodes in the communication dimension are embedded into hello bag. For localization, the received signal strength indication (RSSI) is used instead of geographical information. The more track technique is used for path identification. The sink nodes move horizontally and vertically and cover the whole network. The source node broadcasts information packet directly if the sink node is inside the transmission range. However, if sink node is away from the transmission range, the source node then chooses the best forwarder nodes as relay and destination nodes. Both the relay and destination nodes are chosen by considering the values of the highest remaining energy, and minimum SNR. The destination node secures the two copies of information packet due to cooperation. Which are merged using diversity technique. It increases the link quality but depletes energy of nodes quickly. To maximize the network lifespan and upgrade the entire network throughput, the authors present a routing scheme in [22]. The network is divided into rectangular regions. The mobile sink nodes movements in clockwise directions cover all the regions. The source node transmits a hello packet which contains the information of each neighbor node ID and the information of sink node coordinates. Node broadcasts the information packets directly to the sink nodes due to the movability of the desired sink nodes. The network consumes low energy. However, this approach is deprived of checking the accuracy of the received information. In [23], [PERSON] et al. present a scheme to save energy and enhance the network link quality. The proposed scheme improves the link quality due to the cooperation.