You can find following tools for academic purposes freely. I highlight strength and weakness of each simulator/Emulator used for WSNs. Hope that it will be helpful for you.
Comments of researchers are highly appreciated for improvement of answer.
1. Type of Simulator/ Emulator: NS1, NS-2, NS3
1.1. Nature of simulator/Emulator: General simulator
1.2. Strength/Weakness
Ø It is open source model that saves the cost of simulation, and online documents allow the users easily to modify and improve the codes.
Ø NS-2 and NS3 can simulate the layered protocols and application behaviors. However, It is bit harder to separate the behavior of layers from applications.
Ø It can simulate 400 nodes properly but more than 400 nodes create problem and realistic results cannot be obtained.
Ø It cannot handle problems of the bandwidth properly
2. Type of Simulator/ Emulator: TOSSIM
2.1. Nature of simulator/Emulator: Emulator
2.2. Strength/Weakness
Ø specifically designed for WSNs
Ø Can support thousands of nodes.
Ø Can emulate radio models and code executions.
Ø It can only emulate homogeneous applications.
Ø Have to use Power TOSSIM to emulate power consumption.
3. Type of Simulator/ Emulator: ATEMU
3.1. Nature of simulator/Emulator: Emulator
3.2. Strength/Weakness
Ø It is specifically designed for WSNs
Ø It can provide emulation for different sensor nodes in homogeneous networks or heterogeneous networks.
Ø It can emulate radio channels or power consumptions.
Ø The simulation time is much longer.
4. Type of Simulator/ Emulator: OMNeT++
4.1. Nature of simulator/Emulator: General simulator
4.2. Strength/Weakness
Ø It can provide fully support to MAC and some localized protocols in wireless Sensor networks.
Ø Simulate channel controls and power consumptions.
Ø It has limited capacity for available protocols.
You can find following tools for academic purposes freely. I highlight strength and weakness of each simulator/Emulator used for WSNs. Hope that it will be helpful for you.
Comments of researchers are highly appreciated for improvement of answer.
1. Type of Simulator/ Emulator: NS1, NS-2, NS3
1.1. Nature of simulator/Emulator: General simulator
1.2. Strength/Weakness
Ø It is open source model that saves the cost of simulation, and online documents allow the users easily to modify and improve the codes.
Ø NS-2 and NS3 can simulate the layered protocols and application behaviors. However, It is bit harder to separate the behavior of layers from applications.
Ø It can simulate 400 nodes properly but more than 400 nodes create problem and realistic results cannot be obtained.
Ø It cannot handle problems of the bandwidth properly
2. Type of Simulator/ Emulator: TOSSIM
2.1. Nature of simulator/Emulator: Emulator
2.2. Strength/Weakness
Ø specifically designed for WSNs
Ø Can support thousands of nodes.
Ø Can emulate radio models and code executions.
Ø It can only emulate homogeneous applications.
Ø Have to use Power TOSSIM to emulate power consumption.
3. Type of Simulator/ Emulator: ATEMU
3.1. Nature of simulator/Emulator: Emulator
3.2. Strength/Weakness
Ø It is specifically designed for WSNs
Ø It can provide emulation for different sensor nodes in homogeneous networks or heterogeneous networks.
Ø It can emulate radio channels or power consumptions.
Ø The simulation time is much longer.
4. Type of Simulator/ Emulator: OMNeT++
4.1. Nature of simulator/Emulator: General simulator
4.2. Strength/Weakness
Ø It can provide fully support to MAC and some localized protocols in wireless Sensor networks.
Ø Simulate channel controls and power consumptions.
Ø It has limited capacity for available protocols.