## 6 Simulation Results  
Performance validation of the proposed SiM-RPO and CoSiM-RPO algorithms is done through simulation using MATLAB. The proposed schemes are compared with the existing depth based routing DBR [19], Optimized DBR [20], and Cooperative DBR [23] algorithms. A network having dimensions of 500 m \(\times\)500 m is considered below the ocean surface, as considered in the existing scheme [23]. The network is partitioned into four small squares named TRS, TLS, BRS, and BLS. The MSs move on a predefined triangular path for data collection. The MSs start motion from the defined points in the network. The MS at the center point moves in a diagonal direction towards the corner of the network. When the MS reaches the corner, it moves along the \(x\)-axis or \(y\)-axis. When it reaches to the middle of the network or the other corner of the square, then it starts moving back to its start position. It makes a triangular path, covers the whole network, and obtain access to all the nodes for information and data collection. All the other MSs follow the same procedure to move in a triangular path. The irregular 225 nodes make a connection with MSs through the acoustic link. Therefore, an acoustic modem is embedded with every node. The nodes consume 2 W, 0.8 W, and 8 mW of power while transmitting data, receiving, and in the idle state, respectively. An equal amount of energy is given to every sensor node at the initial stage. The info packet size is 48 bits. The data packet size is 1600 bits and transmitted with a rate of 10 kbps. Table 1 provides a summary of the simulations undertaken. The water flow disturbs the nodes' position. Therefore, the nodes move randomly and are not static. Before the transmission or exchanging of the data, the MAC protocol senses the channel as used in [39]. The three-way handshaking MAC protocol is used. The MS initiates info packet for their presence, as well as an indication that the MS is ready to receive data from the nodes. When the node hears info packet, then it transfers data to the MS. When the MS receives data, then it sends acknowledgment to the sender. The data are delivered to the destination by the source if the channel is free. Otherwise, after several attempts, the data are dropped. Figure 6 indicates the cost paid as regards consumed energy. The energy consumed in the proposed schemes is the lowest than existing schemes. In the proposed SiM-RPO algorithm, the MSs moves in the network for the collection of the data, and direct transmission is done between the source and MS. Due to the direct transmission of the data with MSs, it reduces the energy cost of the network, and almost only one node involves in data exchanging, which leads to less energy consumption, while \begin{table}
\begin{tabular}{c l l} \hline \hline
**S.No** & **Parameter** & **Value** \\ \hline
1 & Network size & 500 m \(\times\)500 m \\
2 & Number of nodes & 225 \\
3 & Sink nodes & 4 \\
4 & Initial energy & 20 joules \\
5 & Transmission range & 130 m \\
6 & Frequency & 30 kHz \\
7 & Data packet size & 1600 bits \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Parameters. in the CoSiM-RPO, two nodes involve in data forwarding due to which more energy is consumed than the SiM-RPO algorithm, while in DBR, ODBR, and CoDBR, data delivery through multiple hops for a single packet to the sink is used. Multiple nodes involve in data transmission, which leads to extra energy being consumed, and as a result, the network has a greater energy consumption than the proposed SiM-RPO algorithm. The consumed energy of CoSiM-RPO is greater than SiM-RPO due to the cooperative technique. The relay node transmits data to the MS when it receives a request from the MS, which leads to excessive energy consumption, while the energy expenditure of the CoSiM-RPO is the lowest among the existing algorithms.