What is correct to calculate Rate or shannon capacity?

Users are uniformly distributed in the circular area and base station is at the center. If the distance is varied then their corresponding rate should also be different. Here is the code, I am getting the approximate same rate for all users. Where is the mistake in my code? any suggestion is very thankful.

n_users=10;%no. of users
N0dbm=-124; %%%noise power
N0 = 10^((N0dbm-30)/10); 
P_MBS=20;%Power in watt
MBS_XY = [0 0]; 
r_MBS=100;
alpha=0.3; %bandwidth allocation
FREQ = 2.15;
angle_users = 2*pi*rand(n_users,1); 
r_users = r_MBS*sqrt(rand(n_users,1));
 %x and y coordinate of users
     X_users = r_users.*cos(angle_users)+ MBS_XY(1);
     Y_users = r_users.*sin(angle_users)+ MBS_XY(2);
     XY_users=X_users + 1i.*Y_users;
MBS_XY = MBS_XY(1)+1i*MBS_XY(2);
%%Calculate channel gain
dist_users = abs(XY_users-MBS_XY);
path_loss = 10*alpha*log10(dist_users) + 27.3 + 26*log10(FREQ);
shadowing = 4*ones(size(dist_users));
shadowing = shadowing.*randn(size(shadowing));
sub_power_array = 10.^((shadowing-path_loss)./10);      % caculate shadowing
size_h = size(sub_power_array); % caculate h
h = sqrt(0.5)*randn(size_h)+sqrt(0.5)*randn(size_h)*1j;
% final power array
channel_gain = (abs(h)).^2.*sub_power_array;
G_MBS = channel_gain;
%%%%
%%Rate
R_MBS = log2(1+(P_MBS.*G_MBS)./N0); %%Rate or shannon capacity

Answer 1

[KALYAN ACHARJYA]

The output is not same, where you got the same results if you vary the n_user

[KALYAN ACHARJYA]

All parameters are fixed in the code, only one variable is "n_user", clarify, am I right?

Note on following two statements also having rand function-generates random..

% code
angle_users = 2*pi*rand(n_users,1); 
r_users=r_MBS*sqrt(rand(n_users,1));

[Praveen Pawar]

thanks for your kind response sir. My doubt is that if users are randomly distributed in the area, some are very near to base station and some at the edge of the cell. Then why not more variation in the rate?

[KALYAN ACHARJYA]

Agreed that you have varied the n_user value, the n_user value is used to find the following-

% code
angle_users = 2*pi*rand(n_users,1); 
r_users=r_MBS*sqrt(rand(n_users,1));

Here rand-means random, check the angle user and r_user are not varied much. There may be following options to change the RMS in diverse.

[KALYAN ACHARJYA]

??

[Praveen Pawar]

Sir, there is no issue with the uniformly distributed random numbers. If above code is ok, then I need to find the basic conceptual answer. However, something is missing in my code. First, there is no significant variation on the basis of distance between base station (BS) and users. Second, while changing BS power from 20 to 2 watt, still, there is small change in rate.

[KALYAN ACHARJYA]

Why not plot Shannon's capacity limit graph, you will get the clue whether the results are OK or not?