Visible Light Communication (VLC) indoor positioning based on Received Signal Strength (RSS)

I need to obtain the estimated distance from the Received Signal Strength (RSS) through the Lamberian equation.

these are my four optical signals from four LEDs:

LED1_sig= 0.5*square(2*pi*1000*t , 50)+0.5;

LED2_sig= 0.5*square(2*pi*1250*t , 50)+0.5;

LEDs_sig= LED1_sig + LED2_sig;

Can anyone help me in this issue???

Any one can help??

[Walter Roberson]

Please read http://www.mathworks.com/matlabcentral/answers/6200-tutorial-how-to-ask-a-question-on-answers-and-get-a-fast-answer

Also, those images are too low resolution for many of us to read.

Answer 1

[Garmit Pant]

Hello Aly Khafagy,

I understand that you require the estimation of the distance between an LED transmitter and receiver using the Lambertian equation based on the Received Signal Strength (RSS).

While MATLAB lacks built-in functions for this specific calculation, you can model the provided equations in order to estimate the distance.

For typical LEDs havingLambertian radiation order “m”, the received optical power “Pri“ from the “𝑖”th LED transmitter is given by 

Where:

• Pti - the transmitter’s power from the 𝑖th LED transmitter
• di - the distance between the 𝑖th LED transmitter and the receiver
• Apd – the active area of the receiver

Using the assumption that cos(α) = cos(β) = hi/di, we can calculate di as follows:

Following the text attached,

m = 0.512825

Thus, we can find di in MATLAB by modelling the above equation as follows:

D(i) = nthroot((Apd*P_t(i)*power(h,1.512825))/pi*P_r(i),3.512825); 
%P_t - transmitter’s power from the 𝑖th LED transmitter 
%P_r – received optical power from the 𝑖th LED 

You’d need data for both the transmitted and received signals for the above calculations. Given that data is available, along with other parameters, the distance between an LED transmitter and receiver can be calculated.

Please refer to the following documentation as well:

Guide for the “nthroot” function- https://in.mathworks.com/help/symbolic/nthroot.html

I hope you find the above explanation and suggestions useful.

Garmit Pant