how to measure SNR in cooperative communi for MRC

[shakeel006]

I have relay cooperative communication system.two relays and 2 data nodes.
some defination in MATLAB codes for my simulation are as follows
s1 = randint(N,1,[0 M-1]);
x1 = symbols(s1+1);

s2 = randint(N,1,[0 M-1]);
x2 = symbols(s2+1);

h11 = sqrt(0.5) * randn_c(N);
h21 = sqrt(0.5) * randn_c(N);
h12 = sqrt(0.5) * randn_c(N);
h22 = sqrt(0.5) * randn_c(N);

h1_1 = abs(h11).^2;%T1R1
h2_1 = abs(h21).^2;

h1_2 = abs(h12).^2; %T1R2
h2_2 = abs(h22).^2;

nr1 = sigma1*randn_c(N);
n11 = sigma1*randn_c(N);
n21 = sigma2*randn_c(N);

the received signal at r1 and (r2 relay 2 ) relays is as follows

r1 = sqrt(E1).* h11 .* x1 + sqrt(E2).* h21 .* x2 + nr1;
r2 = sqrt(E1).* h12 .* x1 + sqrt(E2).* h22 .* x2 + nr2;

the signal received at Data nodes rd1 and rd2 after normalization .i.e the received signal at rd1 is as follows
rd1=sqrt(A1) .*h11.*conj(h12).*conj(x2)+ nt11;

where
A1=ER1.*E2./(ER1.*h1_1+(E1+E2+1));
B1=ER2.*E1./(ER2.*h2_1+(E1+E2+1));
nt11=sqrt(ER1.*h11.^2./(ER1.*h1_2+(E1+E2+1))).* conj(nr1) + sqrt((E1+E2+1)./(ER1.*h1_1+(E1+E2+1))).*n11;

nt21=sqrt(ER2.*h21.^2./(ER2.*h2_1+(E1+E2+1))).* conj(nr1) + sqrt((E1+E2+1)./(ER2.*h2_1+(E1+E2+1))).*n21;

similarly the signal received at rd2 is as follows
rd2=sqrt(B1) .*h21.*conj(h11).*conj(x1)+ nt21;


I need to apply MRC at rd1 and rd2 will the signal for after MRC at rd1 and rd2 will

rd2=sqrt(B1) .*h2_1.*conj(h11).*conj(x1)+ conj(h21).*nt21;

rd1=sqrt(A1) .*h1_1 .*conj(h21).* conj(x2) + conj(h11).*nt11;

I am unconfident how to apply MRC ,

please guide how can I apply in general what I know is
%let r1 is received signal at data node d1 then MRC is just conjugate that channel from where it came i.e
%r1mrc=conj(h1).*r1;

I shall be very grateful to all for any help
Regards