I am assuming that you want the code for a MIMO system.
Here is a basic code that I wrote some time ago
% Note: This is a basic combine MATLAB code for distributed rate and power control protocol in wireless communication.
count_antennas = 4;
count_users = 4;
snr_target = 20; % target SNR in dB
p_max = 10^(0.1*10)*ones(n_users, 1); % maximum transmit power of each user
% initialize variables
h = randn(count_users, count_antennas); % channel matrix for each user
p = zeros(count_users, 1); % transmit power of each use
rate = zeros(count_users, 1); % data rate of each user
rate_total = 0; % total data rate across all users
% iteratively adjust transmit power and rate allocation until convergence
while true
% calculate the channel inversion matrix for each user
w = zeros(count_users, count_antennas);
for i = 1:count_users
w(i,:) = h(i,:)'/(h(i,:)*h(i,:)'+eps);
end
% calculate link SNR and rate for each user
for i = 1:count_users
snr = p(i)*w(i,:)*h([1:i-1 i+1:end],:)*(w([1:i-1 i+1:end],:)*h([1:i-1 i+1:end],:)'+eye(n_antennas))+eps;
rate(i) = 1/2*log2(1+snr);
end
% update the value of the total rate
rate_total_prev = rate_total;
rate_total = sum(rate);
% calculate the absolute difference in total rate from the target
rate_diff = abs(rate_total - snr_target);
% if target rate is achieved or iterations exceed a threshold, stop iterating
if rate_diff < 0.01 || abs(rate_total - rate_total_prev) < 0.01 || iterations > 20
break
end
% adjust transmit power and rate allocation
for i = 1:count_users
p(i) = max(min(p_max(i), p(i)*2^(rate_diff/n_users/rate(i))), 10^(-10)); % iterative power control
end
end
disp("Powers:");
disp(p);
disp("Rates:");
disp(rate);
