# Internet of Things in Marine Environment Monitoring: A Review
## 4 New Technologies for Marine Environment Monitoring and Protection
### New Communication Routing Protocols  
With the advancement of communication technologies, new communication routing protocols have been proposed and developed for marine environment monitoring systems. [PERSON] et al. [89] proposed a chromosome (routing path), which consists of sequences of non-negativity integers that denote the IDs of genes (CH nodes) through which a routing path passes. In a routing path, the  
\begin{table}
\begin{tabular}{p{71.1 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Category** & **Main Idea** & **Advantages** & **Disadvantages** \\ \hline \multirow{6}{*}{Power control based} & The proper transmission power level is assigned to each node to guarantee enough signal strength at the receiver that it can successfully receive and decode the transmitted message & Simple; scalable; conserves energy; does not change the sensing coverage; can overcome time-varying acoustic channel quality. & May diminish the network connectivity; increases the number of hops and end-to-end delay. \\ \hline \multirow{6}{*}{Wireless interface mode management based} & The wireless interface of nodes alternates between active, sleeping, and powered-off modes. This change reduces the amount of unnecessary time a node spends listening to the channel. & Simple; scalable; conserves energy relative channel polling; does not change sensing coverage. & Changes network density; changes routing paths from time to time; increases delay. \\ \hline \multirow{6}{*}{Mobility assisted based} & Some mobile nodes are moved to new locations in different depths or with a predetermined trajectory, creating new interconnections. & Improves network connectivity; deals with network partitions; improves data collection from hop spots. & Needs trajectory planning procedures; increases energy cost for mobility; may change sensing coverage. \\ \hline \hline \end{tabular}
\end{table}
Table 2: Classification of Topology Control Algorithms for underwater wireless sensor networks (UWSNs).  
order of each CH is represented by the locus of chromosome in which the gene of the first locus is always reserved for the source CH nodes. A looping feature of selection (\(\phi\)s), crossover (\(\phi\)c), and mutation (\(\phi\)m) operators is applied on each individual to improve the quality of the solution through the pre-defined probabilities (\(\phi\)p) until the termination criterion is satisfied. The probability of the mutation rate increases from an extremely low value of 0.01 to its maximum value of 0.05. Highly stable small clustering mechanism is used to organize sensor nodes into a connected hierarchy for distributing energy and data traffic load evenly in the network.  
The protocol proposed by [PERSON] et al. [90] is called balanced energy adaptive routing (BEAR). It exploits the location information, selects the neighbors, chooses the facilitating and successor nodes based on cost function value, and finally selects the forwarder node that has residual energy more than the average residual energy of the network. BEAR allows nodes to communicate directly with the sink node leading to an increase in the number of packets being dropped.  
[PERSON] and [PERSON] [91] proposed an enhanced duty cycled multiple rendezvous multichannel media access control (DMM-MAC) for handling more volume of data in multi-hop underwater wireless sensor networks (UWSNs) for marine eco systems. This protocol distributes bursty sensor data by dynamically tuning the duty cycles, and hence network performance is enhanced dramatically. It is equipped with one modem and the propagation delays or relative distances need not to be known by the other nodes in the network. Less energy is consumed, and it is easy to forward the data based on priority. One cycle consists of several frames and is subdivided into an active section and a sleep section. Each node can use the other time slot when the time slot is free.