## 6 Simulation Results and Discussions
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Protocol**} & \multirow{2}{*}{**Depth Threshold (d\({}_{th}\))**} & \multirow{2}{*}{**Sink Mobility**} & \multicolumn{2}{c}{**Parameter for Forwarder**} \\  & & & **Routing** & **Node Selection** \\ \hline \multirow{2}{*}{**DBR**} & \multirow{2}{*}{Fixed} & Static sinks & Multi-hop & \multirow{2}{*}{} \\  & & (on water surface) & routing & Depth \\ \hline \multirow{2}{*}{**EEDBR**} & \multirow{2}{*}{Fixed} & Static sinks & Multi-hop & \multirow{2}{*}{} \\  & & (on water surface) & routing & Depth and residual energy \\ \hline \multirow{2}{*}{**CoDBR**} & \multirow{2}{*}{Fixed} & Static sinks & Cooperative & \multirow{2}{*}{} \\  & & (on water surface) & routing & Depth \\ \hline \multirow{2}{*}{**iAMCTD**} & \multirow{2}{*}{Variable (on basis of & \multirow{2}{*}{} \\  & network density information)} & \multirow{2}{*}{Mobile courier nodes} & Multi-hop & Depth, residual energy \\  & & & routing & and link’s SNR \\ \hline \multirow{2}{*}{**DEADS** **(proposed)**} & Variable (on basis of one-hop & \multirow{2}{*}{} \\  & neighbor information) & Mobile sinks & \multirow{2}{*}{} \\  & & & routing & Depth and residual energy \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Analysis of existing depth-based routing protocols. forwarding and constant \(d_{th}\). DBR and CoDBR neglects both residual energy of nodes as well as link state in terms of SNR, whereas, EEDBR neglects link state which badly affects network throughput of these protocols. Number of dead nodes sharply increases with time in EEDBR as there is high load on high energy nodes because of considering residual energy as a routing metric. In CoDBR, network density decreases at the fastest rate because of cooperative routing being performed. Cooperative routing involves high energy consumption because of multiple transmissions and receptions of same data packet. Stability period (time up till which all nodes in the network are alive) of iAMCTD is highest because of optimal \(d_{th}\) selection. Also, in iAMCTD, only source node transmits data to its next hop neighbor which conserves energy and results in improved stability period. Although due to implementation of rule 4, \(d_{th}\) selection is more optimized in DEADS-SRC and DEADS-MRC as it requires only one-hop neighbor information instead of complete network density information, however, data is transmitted from source node as well as relay node(s) to the next hop. So, it is consuming 2 (SRC) to 3 (MRC) times more transmission and reception energy than iAMCTD due to which stability period is compromised. This shows the tradeoff between network stability period and reliability. DBR shows better energy management than EEDBR as shown in Figure 11. In DBR, network residual energy steadily decreases as total number of eligible neighbors drops off with network density. Energy consumption of EEDBR is the highest among all other protocols due to frequent selection of high energy nodes. Moreover, higher energy consumption in DBR, EEDBR and CoDBR is because of reactive routing being performed in these protocols. Although CoDBR attains data reliability and high throughput, however, energy consumption is highest because of cooperative routing in the network as well as flooding resulting from fixed \(d_{th}\). iAMCTD attains a balanced residual energy throughout the network lifetime due to proper forwarder selection, optimal mobility patterns of courier nodes and maintenance of uniform network density. In DEADS-SRC and DEADS-MRC, high energy consumption is involved as compared to iAMCTD. This high energy consumption is because of cooperative routing. In the proposed protocol, as the network starts, nodes become active and start the sensing and transmission process. Initially all nodes are alive, each node finds appropriate relay and destination nodes and performs transmission and reception process due to which energy consumption is increased. After certain time, rate at which nodes become dead increases and energy consumption decreases.