# Cooperative Opportunistic Pressure Based Routing for Underwater Wireless Sensor Networks
## 3 Our Proposed Work
\begin{table}
\begin{tabular}{p{108.4 pt} p{108.4 pt} p{108.4 pt} p{108.4 pt}} \hline \hline
**Protocol** & **Feature** & **Achievements** & **Limitation** \\ \hline GEDAR [2] & Geo-opportunistic routing protocol. network throughput & Avoid void hole occurrence, recover void holes, high network throughput & High end to end delay and energy consumption during node recovery from void hole by depth adjustment mechanism. \\ \hline \hline Hydroficcat [4] & Pressure based routing for UWSNs, opportunistic routing to recover data from void nodes. incremental best relay cooperation on demand. & Utilize the duplicate packets transmission of opportunistic routing to recover data from void nodes. Saves channel resources and low processing overhead. High packet drop ratio and low network lifetime. \\ \hline VARP [6] & Void aware depth based routing. node mobility and reduction in packet drop ratio. & Reduction in recovery fulbacks, efficient handling of node mobility and reduction in packet drop ratio. & High energy consumption and end to end delay. \\ \hline Energy efficient cooperative communication for data transmission [7] & Cooperative communication. & Improvement in packet transmission in busy network. & Low performance in sparse network conditions. \\ \hline DRB [8] & Depth based routing. & High packet delivery ratio in dense network. & High load on low depth nodes, redundant packet transmissions. Energy balancing and improvement in packet delivery & Redundant packet transmission and high energy consumption in danger networks. \\ \hline \hline WEADER [9] & Depth and residual energy based routing. & Energy balancing and improvement in packet delivery ratio. & Finding 2 hop neighbors does not eliminate the occurrence of void hole \\ \hline H2-DAB [11] & Multi hop dynamic addressing based routing. & High data packet delivery ratio and prolonged network lifetime. & High latency, high load on low depth nodes and processing overhead. \\ \hline AURP [12] & Use of AUVs as relay nodes. improvesnet in data packet delivery and reduction in energy consumption. & High control messages exchange overhead. \\ \hline ERPR2 [13] & Residual energy and distance based routing. & Low latency and energy efficiency. & Redundant packet transmissions and low performance with increased mobility of nodes. \\ \hline DEADS [14] & Snik mobility, single and multiple relay cooperative routing. & Increase in throughput and reduction in packet drop ratio. & High energy consumption and high control messages exchange overhead. \\ \hline Energy and time efficiency in depth based routing [15] & Time of arrival (ToA) ranging technique. & Reduction in energy consumption from multi path forwarding demands. & High end to end latency. \\ \hline Joint cooperative routing and power allocation [16] & Cross layer cooperative routing & Relatively lower collision probability compared to other cooperative schemes. & Not applicable for time critical applications. \\ \hline Delay and lifetime performance [17] & Routing using mobile sink. & Increment in network lifetime and packet delivery ratio. & No time bound for data transfer in case of random mobility of sink resulting in mobile sink buffer overflow. \\ \hline BTM [18] & Optimum transmission distance to the sink & Improvement in network lifetime, balanced energy consumption & Transmission loop formation and high energy consumption in case of direct transmission over long distances. \\ \hline Energy efficient cooperative communication [19] & Clustering and cooperative communication & Energy efficiency relative to direct transmissions. & High energy consumption in cluster formation. \\ \hline Enhanced energy balanced data transmission [20] & Balanced energy transmission. & Improvement in network life time, high throughput and low packet drop ratio. & Throughput and network lifetime decreased with increased network radius. \\ \hline \hline \end{tabular}
\end{table} 
Table 1: State of the art related work.