What is the relationship between transmission power and transmission range when communication medium is acoustic waves e.g in underwater sensor networks? What parameters must be considered for this relationship. I'll appreciate if you can suggest a mathematical equation for this.
*Please share your input for radio based communication if not acoustics.
transmission range is directly proportional transmission power
@Sukhwinder Singh Sran Thanks you for your reply...I understand that they are directly proportional but want to know the equation between the two. In other words I want to know what is "G" in the following equation.
x=G*y
where "x" represents transmission range and "y" represents transmission power. Moreover as G may be dependent on many factors e.g attenuation, propagation delay etc, i will appreciate if u can help me with all the factors that determine G.
It determines distance, soft and hard partions between transmitter and reciever, SINR, noise factors, channel power and interference's..
Thanks
You may have to use the free path loss to see the effect of increasing the transmitted power in the transmission range:
https://en.wikipedia.org/wiki/Free-space_path_loss
For example you can suppose that P1 is the threshold for receiving signal and suppose that it is achieved at a distance D1 for a given transmitted power Pt. Then you need to calculate what will be the new distance D2 where your receive the same power P1 if the transmitted power Pt is increased by a certain amount. You can plot the power as a function of the distance P(d) before and after increasing Pt.
For radio communications, Friis transmission equation shows the parameters. Knowing the required power at the receiver and the other parameters you can solve for transmission range.
https://en.m.wikipedia.org/wiki/Friis_transmission_equation
Note that according to this equation, x^2=G*y, not x=G*y
When we have a point transmitter (isotropic) in an absorptionless media. Then its power is homogeneously distributed on the outer area of the sphere centered on the the point transmitter. The area of the sphere is give by 4 pi R^2, and accordingly the power per unit area is given by
Pt / (4 pi * R^2),
where Pt is the transmit power. A receiver with an aperture "A" will receive a power of,
Pr = Pt / (4 pi R^2) *A.
In communication systems, you are usually limited by the noise and interference, and you cannot communicate below a certain signal to interference+noise ratio (called the SINR threshold).
You can therefor find form the above relation that the range is proportional to the square root of the transmit power,
Rmax = constant * sqrt (Transmit power)
The propagation of the acoustic wave is similar to the propagation of the radio waves. So, if you have an acoustic transmit power Pt, the distance of the receiver from the transmitter is R and the propagation is a line of sight then the received power intensity will be Pt/ 4piR^2 assuming isotropic radiator other wise one has to take the radiation angle into consideration. Assume that the receiver detector area= Ar , then the received power Pr= Ar Pt/ 4piR^2= G Pt,
Then G in this case = Ar / 4piR^2 , you can use channel models by analogy to the radio waves such as Riceian and Rayleigh channels. The analogy between the acoustic waves and the em waves enables one to borrow the channel models and applies them on the sound and ultrasound systems.
Best wishes
Friis transmission equation is used to estimate range based on transmission power.
Please guide me that in free space EM wave propagation model Transmitted power to antenna is given. Why not we directly calculate the power received in far field using Frii's equation when Transmitted power, Antenna gains, wavelength is given. Why we are calculating received power at distance d by first calculating the received power at some reference point near antenna but outside near field? i.e. outside fraunhoffer distance. Actually both powers are with reference to power transmitted and either we calculate received power with respect to transmitted power or with respect to referenced received power near antenna, the answer will be same. Thanks in advance. I know that at transmission point of power the distance is zero but then again we already have transmitted power given at distance zero so we dont need Frii's equation at distance zero.
(r) = received , (t) = transmitted, d0 = d knot
P(r) at distance d = P(t) G(t) G(r) ( lambda/4 x pi x d)^2
P(r) at distance d = P(r) at some reference distance d0 x (d0/d)^2
I want know that whether the transmitter power will be constant?
Because if I want to calculate path loss by formula PL=Pt-Pr.. In this Pt remains constant?
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