Several tools can simulate multi-hop underwater acoustic networks, each with its own strengths and weaknesses. Some of the most popular tools include:

• OPNET: OPNET is a commercial network simulator that can be used to simulate a wide variety of network types, including underwater acoustic networks. It is a powerful tool that can be used to model complex network topologies and protocols, but it can also be expensive and time-consuming to learn.📷Opens in a new window📷www.researchgate.netOPNET simulator
• NS-3: NS-3 is an open-source network simulator that is popular for research in underwater acoustic networks. It is less powerful than OPNET, but it is more affordable and easier to learn. NS-3 also has a large community of users, which makes it easier to find help and support.📷Opens in a new window📷www.nsnam.orgNS3 simulator
• Aqua-Sim: Aqua-Sim is an open-source network simulator that is specifically designed for simulating underwater acoustic networks. It is based on the NS-2 simulator, and it includes a number of features that are specifically relevant to underwater acoustics, such as models for absorption, scattering, and Doppler shift.📷Opens in a new window📷www.kasbox.comAquaSim simulator
• WOSS: WOSS (World Ocean Simulation System) is a closed-source network simulator that is used by the US Navy. It is a very powerful tool that can be used to simulate large, complex underwater acoustic networks. However, WOSS is not available to the public.📷Opens in a new window📷www.researchgate.netWOSS simulator
• GlomoSim: GlomoSim is an open-source network simulator that can be used to simulate a wide variety of wireless networks, including underwater acoustic networks. It is based on the OMNeT++ simulator, and it includes a number of features that are specifically relevant to underwater acoustics, such as models for absorption, scattering, and Doppler shift.📷Opens in a new window📷networksimulationtools.comGlomoSim simulator
• UWanSim: UWanSim is an open-source network simulator that is specifically designed for simulating underwater acoustic sensor networks. It is based on the OMNeT++ simulator, and it includes a number of features that are specifically relevant to underwater sensor networks, such as models for energy consumption and node mobility.📷Opens in a new window📷simnovus.comUWanSim simulator

The best tool for simulating multi-hop underwater acoustic networks will depend on the specific needs of the user. If the user needs a powerful tool that can be used to model complex network topologies and protocols, then OPNET or WOSS may be a good choice. If the user is on a budget or needs a tool that is easy to learn, then NS-3 or Aqua-Sim may be a better choice. If the user needs a tool that is specifically designed for underwater sensor networks, then UWanSim may be a good choice.

In addition to the network simulators listed above, there are also a number of channel modeling tools that can be used to model the underwater acoustic channel. These tools can be used to generate realistic channel models that can be used as input to network simulators. Some of the most popular channel modeling tools include:

• BELLHOP: BELLHOP is a ray-tracing model that can be used to model the propagation of sound in the ocean. It is a very accurate model, but it can be computationally expensive to run.📷Opens in a new window📷patel999jay.github.ioBELLHOP simulator
• Kraken: Kraken is a propagation model that is based on ray tracing and normal mode superposition. It is less accurate than BELLHOP, but it is also less computationally expensive.📷Opens in a new window📷www.amazon.comKraken simulator
• CWAP: CWAP is a propagation model that is based on parabolic equation methods. It is the least accurate of the three models, but it is also the least computationally expensive.📷Opens in a new window📷www.ebay.caCWAP simulator

The best channel modeling tool for the user will depend on the specific needs of the user and the computational resources available. If the user needs a very accurate model, then BELLHOP is a good choice. If the user needs a model that is less accurate but more computationally efficient, then Kraken or CWAP may be a better choice.

Once the user has chosen a network simulator and a channel modeling tool, they can use them to simulate their underwater acoustic network. The simulator will generate a number of performance metrics, such as throughput, delay, and packet loss. These metrics can be used to evaluate the performance of the network and to compare different network designs.

The currently available tools are:

1. NetSim - https://www.tetcos.com/underwater_networks.html

2. Aqua sim, based on NS-2 - https://github.com/rmartin5/aqua-sim-ng

For multi-hop, data passes through multiple underwater devices nodes before reaching its destination. This type of simulation needs ad hoc routing where each underwater devices can act as a router. NetSim has one example of ad hoc routing for underwater networks using depth-based routing (DBR). DBR is a ad hoc routing protocol for underwater wireless networks. It utilizes the depth of nodes to make forwarding decisions. The document (https://www.tetcos.com/pdf/v13.3/NetSim-UWAN_DBR-protocol-implementation.pdf) provides implementation details of DBR in NetSim.

Have you worked with NetSim or depth-based routing before?