**Underwater IoT Communication Calculator**

**More Information: :**

**Algorithm for Radio Frequency Communication Method**

**'CLICK HERE FOR SOURCE'**

The propagation speed underwater is directly proportional to the frequency and given by Equation,

Vrf= √(f*(10^7)/δ) m/s

Where,

F is frequency in MHz

δ is conductivity underwater which is 4 simens/m.

**Algorithm for Acoustic Communication Method**

**'CLICK HERE FOR SOURCE'**

The distance along the direct path is calculated as:

D = √(R^2+(d1–d)^2) meters.

Where,

d1 is the depth of the source node, d2 is the depth of the receiver, his the depth of the area considered and R the transmission range.

**Algorithm for Optical Wireless Communication Method**

**'CLICK HERE FOR SOURCE'**

Generally, to describe the propagation in water of collimated light in low scattering regimes, the spectral beam attenuation coefficient c(λ) is used; this parameter is wavelength function. This coefficient is a sum of the effects of the absorption coefficient and of the scattering one, respectively called a(λ) and b(λ), and so defined as:

c(λ)=a(λ)+b(λ)

Have a look at the table below to get more information:

*Source: Schirripa Spagnolo, G., Cozzella, L., & Leccese, F. (2020). Underwater Optical Wireless Communications: Overview. Sensors (Basel, Switzerland)* Therefore, the measured distance L can be calculated as:

L = ½ (N(1/f).(c(λ)/Ng)+ d)

Where, N is integer value should be 2,

F = Frequency

c(λ) = Attenuation coefficient

Ng = Refractive index which is '1.3'.

**Algorithm for Audio Communication Method**

**'CLICK HERE FOR SOURCE'**

Dealing with few factors to arrive at values for bulk modulus and density, and thence sound speed, is very cumbersome. To overcome this, numerous empirical relationships have been developed for converting the factors directly to sound speed. A simplified version of such sound speed equations developed by Wilson in 1960 is present below:

C = 1449 + 4.6T + 0.055(T^2) + 0.003(T^3) + (1.39 - 0.012T)(S - 35) + 0.017D

Where,

T = Temperature in degrees Celsius

S = Salinity in parts per thousand

D = Depth in meters

**Conditions/Limits:** "This calculator only works for horizontal communications. It is not suitable for diagonal or vertical communications. It is not suitable for communications across different ocean zones."

*This Calculator is for reference purposes only.