the main pf cose is pahse estimate and analyze the performance but why i get a fixed plotting point etheir the values must be changed

%phase astimation using monte carlo

clear all

close all

clc

%signal model x(n)=Acos(2pif0n+thetha)+w(n)

phase=0.785;

A=1;

sigma=0.1;

f0=0.035;

SNR=[-20:5:10]

% SNR=(A^2/2*(sigma^2))

m=length(SNR);

b=zeros(1,m);

mse=zeros(1,m);

var=zeros(1,m);

mat=zeros(5,1);

for m=1:length(SNR)

M=5;

for i=1:M;%M realisations

s=A*cos(2*pi*f0*i+phase);

% w=wgn(1,5,5)

w=randn(size(s));

x(i)=s+w %signal model

y1=sum(x(i)*sin(2*pi*f0*i))

y2=sum(x(i)*cos(2*pi*f0*i))

phasehat(i)=-atan(y1/y2)%MlE phase estimation

end

% mat(i,:)=phasehat

%compute bias

b(m)=(1/M)*sum(mean(phasehat(i))-phase)

%mean square error

mse(m)=mean((phasehat(i)-phase)^2)

%variance

var(m)=1/M*(sum((phasehat(i))-(1/M*sum(phasehat(i))))^2)

end

figure(1)

scatter(SNR,b)

title('ploting bias')

xlabel('SNR')

ylabel('bias')

figure(2)

scatter(SNR,10*log(mse))

title('ploting mse-mean square error')

xlabel('SNR')

ylabel('mean square error')

figure(3)

scatter(SNR,var)

title('ploting varance')

xlabel('SNR')

ylabel('variance')