Given number of base stations and users , how can I accociate each user to the nearest base station?

I deployed the BSs and Users randomly according to Binomial Point Process, and I assumed to connect each user to nearest BS. So, how can I accociate these users in matlab.

thanks in advance

ro=500; %  radius of the layout circle 
NumBSs=10;  %  Number of Base stations
NumUEs=50;   %Number of users
center=[0 0]; % center of the circle
          
theta_BSs=2*pi*(rand(NumPoints,1)); % distributed random number of Base stations
g = 0.5 * ro + 0.5 * ro * rand(NumBSs,1); 
PosBSs_x=center(1)+g.*cos(theta_BSs);
PosBSs_y=center(2)+g.*sin(theta_BSs); 


theta1 = rand(NumUEs, 1) * 2*pi; % distributed random number of Users
r1 = ro * sqrt(rand(NumUEs, 1));
PosUE = [r1 .* cos(theta1(:)) + center(1),r1 .* sin(theta1(:)) + center(2)]; 

% Initial plot objects
hfig = figure('Color', 'w');
hax=axes('parent',hfig);
% Plot of deploying  points
hdots=plot(PosBSs_x(:,1),PosBSs_y(:,1),'bp',PosUE(:,1),PosUE(:,2),'r.','MarkerSize', 12);       
grid on
hold(hax, 'on')    
axis(hax, 'equal')
% Plot the layout as circles
t = linspace(0, 2*pi);
plot(ro * cos(t) + center(1),ro * sin(t) + center(2))

Answer 1

[Walter Roberson]

pdist2() the coordinates of the stations against the coordinates of the base stations to find the distance from each station to each base station. Then min() along the appropriate axes to determine the index to use.

[omar th]

Please, how can I insert the gNB in the same figure and let it treat the users as the drone-BS do, which means let the users that located near to the gNB connected to it and the others connect to the Drone-BSs as shown in the figure? please find the attached code

ro=500; % radius of the layout circle

NumDroneBSs=20; % Number of drone-Base stations

NumUEs=100; %Number of users

center=[0 0]; % center of the circle of layout

NumgNB=1; % Number of gNB

rgnb= 0; % raduis of gNB to fix it in the center of the layout circle

theta_DroneBSs=2*pi*(rand(NumDroneBSs,1)); % distributed random number of Drone Base stations

g = 0.5 * ro + 0.5 * ro * rand(NumDroneBSs,1);

PosDroneBSs_x=center(1)+g.*cos(theta_DroneBSs);

PosDroneBSs_y=center(2)+g.*sin(theta_DroneBSs);

PosDroneBSs=[PosDroneBSs_x PosDroneBSs_y];

theta1 = rand(NumUEs, 1) * 2*pi; % distributed random number of Users

r1 = ro * sqrt(rand(NumUEs, 1));

PosUE = [r1 .* cos(theta1(:)) + center(1),r1 .* sin(theta1(:)) + center(2)];

theta = rand(NumgNB, 1) * 2*pi; % distributed ground BS

r = rgnb * sqrt(rand(NumgNB, 1));

PosgNB_x= [r .* cos(theta(:)) + center(1)];

PosgNB_y = [r .* sin(theta(:)) + center(2)];

PosgNB = [r .* cos(theta(:)) + center(1),r .* sin(theta(:)) + center(2)];

distances = pdist2(PosDroneBSs,PosUE); % distance between drone-BSs and users

[~, assigned_BS] = min(distances, [], 1);

distances1 = pdist2(PosgNB,PosUE); % distance between ground NodeB and users

[~, assigned_gNB] = min(distances1, [],1);

% Initial plot objects

figure

plot([PosUE(:,1) PosDroneBSs_x(assigned_BS)].', [PosUE(:,2) PosDroneBSs_y(assigned_BS)].', ...

'color',[0 0 1]);

figure

plot([PosUE(:,1) PosgNB_x(assigned_gNB)].',[PosUE(:,2) PosgNB_y(assigned_gNB)].', ...

'color',[0 0 1]);

grid on

hold on

axis equal

% Plot the layout as circles

t = linspace(0, 2*pi);

plot(ro * cos(t) + center(1),ro * sin(t) + center(2))

[Walter Roberson]

I do not know what a gNB is?

[Walter Roberson]

pdist2() the coordinates of the users against the coordinates of the base stations (together with the gNB) to find the distance from each user to each base station together with the gNB. Then min() along the appropriate axes to determine the index to use.

[omar th]

But I deployed the drone Base stations (Nodes) and ground base station (gNB=Node) seperately, so when I tried to gether them, I got an error " Dimensions of arrays being concatenated are not consistent"

How could you help me with this issue ?

Thanks for your response

[Walter Roberson]

For the purposes of pdist2(), you should be using rows in which each row represents one point. If some of your coefficients are represented by columns instead of rows, transpose them.

If you base stations and ground base station are represented by different spatial dimensions (for example, 2D for base stations but 3d for ground base stations), then you need to convert the coordinates to all be the longer length, perhaps by padding with zero.