Matlab code for MIMO-OFDM including BER, SNR, reyleigh. etc

function [Eopt,Tn]=optimal_energy(T,n,C,D,R,s,PR)

%---------------------------------------------------------------
%This algorithm uses binary search for achieve a solution
%to compute the optimal energy for each node when all the  
%nodes have the same energy levels.

%Based on paper: "Energy-Efficient Multi-Hop Packet Transmission
%using Modulation Scaling in Wireless Sensor Networks"

%---------inputs----------------------------------------
%T is the delay constraint in our system
%n is the number of transmitting nodes in the path
%C is a vector(row) that symbolizes the tx power
%D is a vector(row) that symbolizes the electronic power
%s is the packet length in bits
%PR is the precision when searching for the latency constraint
%from T*(1-E) to T*(E+1) --> values of E=from 0.00001 to 0.0001
%--------------------------------------------------------
%------------outputs-------------------------------------
%Eopt is the optimal energy that satisfies the constraints
%Tn is a vector that contains the latency of each node
%--------------------------------------------------------
%conditions for optimality: E(i)=E(i+1) for i=0,1,..,n-1;
%                           sum(Tn)=T;

%---------------------------------
%files asociated to this program:

    %energy_model
    %fixedpoint
    %energy_fixedpoint
%--------------------------------

E=zeros(1,n);  %energy spent of each node
Tn=zeros(1,n); %latency for each node

for i = 1:n,
    Tn(i)=T./n;  
end

%compute the Emin and Emax for t=T/n
for i = 1:n,
    E(i)=energy_model(C(i),D(i),R,s,Tn(i));     
end

Emax=max(E);
Emin=min(E);


%checking if we have already the solution of the problem
j=0;
for i = 1:(n-1),
    if E(i)~=E(i+1)
        j=1;
    end
    
end
%if j=0 we have finished



    
%main body  
%1st-> solve for the new Eopt the latency constraints
%2nd check if is optimal
%3rd if not optimal perform binary search
if j==1
    b=zeros(1,n);
    Tn=zeros(1,n);
    Ts=sum(Tn);
    Eopt=0;
else
    Eopt=E(1);
    %Tn=Tn;
end

while j==1,
   
         Eopt=(Emax+Emin)./2;
         
         for i = 1:n
             E(i)=Eopt;
             b(i)=fixedpoint('energy_fixedpoint',8,1e-6,1000,C(i),D(i),Eopt,s);
         end
         
         
         Tn=s./(b.*R);
         Ts=sum(Tn);
         if (Ts > (T*(PR+1)))   %not optimal
             Emax=Emax;
             Emin=Eopt;
         elseif (Ts < (T*(1-PR)))   %not optimal
             Emax=Eopt;
             Emin=Emin;
         else   %is optimal
             j=0;
         end
            
end

%end of optimal_energy