clear all

R=20*60;         %the update period
H=10;            %the water depth
Et=32.4;
f=50;

for M=1:500
    for i=1:M
        if M<20
            d=50*i;
        else
            d=(1000/M)*i;
        end
        if f<7
            alpha=0.0601*f^0.8552;
        elseif f<21
            alpha=9.7888*f^1.7885*10^(-3);
        elseif f<35
            alpha=0.3026*f-3.7933;
        else alpha=0.504*f-11.2;
        end
        TL=10*log10(d)+alpha*d*10^(-3);
        SL=TL+85;
        It=10^(SL/10)*0.67*10^(-18);
        Pt=2*pi*H*It;
        Pframe(i)=1.23*Pt*(M-i+1)*(1+1/5+1/5+1/25);
        
    end
    pmax=max(Pframe);
    
    Tactive=Et/pmax;
        
    Ttotal=1.23*(M+M/5);
        
    Tlifetime(M)=Tactive/Ttotal*R/24;
  
end
hold on;
M=1:500;
semilogy(M,Tlifetime);
ylim([1,10^8])