%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% This code is to find the best P for max SINR using beta cost function
%
% Made by Jie Lian
% University of Virginia
% 2014/2/12
% USA

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

clc;
clear;
close all;
tic

mimo_h1=load('MIMO_h_1.mat');
mimo_h2=load('MIMO_h_2.mat');
mimo_h3=load('MIMO_h_3.mat');
mimo_h4=load('MIMO_h_4.mat');

mimo_h1=mimo_h1.P_floor_LED_1;
mimo_h2=mimo_h2.P_floor_LED_2;
mimo_h3=mimo_h3.P_floor_LED_3;
mimo_h4=mimo_h4.P_floor_LED_4;

N=2;      % N is the number of transmitters
K=2;      % K is the number of users

% rec_x=[10,25];    % receiver's positions
% rec_y=[20,35];

% rec_x=[10,25,12];    % receiver's positions
% rec_y=[20,35,12];

rec_x=[10,25,12,45];    % receiver's positions
rec_y=[20,35,12,20];

%% establish the mimo channel matrix H
for i=1:K
    H(1,i)=mimo_h1(rec_x(i),rec_y(i));
    H(2,i)=mimo_h2(rec_x(i),rec_y(i));
    %     H(3,i)=mimo_h3(rec_x(i),rec_y(i));
end

%% establish the cdma code matrix C
C=OCDMA(K);

%% establish the Va matrix which represents the expectation matrix
%   Va=E[d'd]
Va=0.25*(eye(K)+ones(K,K));

%% Initial setting, Matrix P and sigma2 of noise
P=zeros(N,K);
sigma2=0.0003;
% P=[5 5;5 5];

P_best=[0 0 ;0 0];
P_l=0:1:10;
L=length(P_l);
SINR_k_o=0;
V=1.e10;      % beta cost function
beta=100;

for ii=1:L
    P_l(ii);
    for jj=1:L-ii+1
        for i=1:L
            for j=1:L-i+1
                
                P(1,1)=P_l(i);
                P(1,2)=P_l(j);
                P(2,1)=P_l(ii);
                P(2,2)=P_l(jj);
                
                for k=1:K
                    W_k(:,k)=W(C,H,P,E(K,k),Va,q(K,k),sigma2,k);
                    SINR_k(k)=SINR(W_k(:,k),C,H,P,E(K,k),Va,A(K,k),sigma2,k);
                end
                
                V_new=sum((1./SINR_k).^(1+beta));
                
                if V_new<V
                    V=V_new;
                    P_best=P;
                    best_SNR=SINR_k;
                    W_best=W_k;
                end
            end
        end
    end
end
P_best
best_SNR
V
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