## 4 Simulation Results  
MATLAB simulates the proposed and counterpart protocols. The network contains 225 nodes which are deployed with irregular spacings. There are four final DNNs, which are static and kept at the water surface. The model initially assigns 10 Joules of energy to every node. The forwarding range of every node is considered 100 m. In the proposed protocols, the depth threshold for the nodes are fixed. A total of 11,200 information bags are transmitted in the direction of final DNN. Some of the packets are dropped due to high BER and many other channel effects, and many of the packets are successfully received at the final DNN. One data bag contains 1600 bits. The MAC layer makes the data link layer (DLL) in the OSI model. The protocol designed for the DLL is MAC. The MAC protocol explains the transmission mechanism of the data packets in a channel [35]. The sensor nodes can move freely without any restriction due to water flow. The speed of sensor nodes due to water currents are approximately up-to 5 m/s [36]. The comparison of the proposed protocols with each other and the Co-DBR protocol for UWSNs is shown in simulation results. The proposed protocols are compared with the Co-DBR because the Co-LFEER and the Co-DBR use cooperative routing, which counteracts channel worst conditions and LFEER also computes links affected by channels. The simulation results indicate that the proposed LFEER algorithm is good in residual energy, alive nodes, dead nodes and delay than the Co-LFEER and the Co-DBR protocols. The Co-LFEER algorithm is better in terms of residual energy, alive nodes, dead nodes and PDR than the Co-DBR protocol. The overall performance of the Co-LFEER is better than the Co-DBR protocol. One round is the time instant responsible for advancement of one or more packets to water surface. The basic information of each protocol LFEER, Co-LFEER and Co-DBR is presented in Table 3.  
The residual energy of the network is presented in Figure 5. The proposed LFEER protocol has the highest residual energy. This is because the information bags are forwarded to the final DNN through one path and neighbor nodes do not cooperate with each other, which consumes extra energy. In the proposed Co-LFEER protocol, residual energy is less than the LFEER protocol due to cooperation technique. However, in the Co-LFEER protocol, the residual energy is higher than the Co-DBR because of the data forwarding with a single relay node in the latter. Although, the residual energy of the proposed LFEER and the Co-LFEER protocols is higher than the Co-DBR up to 600 rounds, from 600 to 900 rounds, the residual energy of all protocols becomes the same because fewer nodes are left in the network that do not participate mainly because majority of the nodes have died. As a result, nodes do not mainly participate in data routing so their energy consumption almost becomes the same. Having more alive nodes guarantees the maximum forwarding of information packets. As a result, it increases the data packets transmission rate towards the sink nodes. Figure 6 shows the proposed LFEER protocol has the maximum alive nodes. This is due to the reason that in the proposed LFEER protocol only one DSN transmits the information bags toward the final DNN. Thus, the least energy is consumed and there are maximum alive alive nodes. The proposed Co-LFEER protocol has more alive  
Figure 5: Residual energy.