Decode 2 transmissions via SIC

can anyone please tell how to decode the signal rx1?? actually i want to transmit two signals: one from the source which when reaches at relay, adds both signals and at receiver using SIC, i have to decode them. Please help.

clc; clear all; close all;

format long;

bit_count = 10000;

Eb_No = -3: 1: 30;

SNR = Eb_No + 10*log10(2);

for aa = 1: 1: length(SNR)

        T_Errors = 0;
    T_bits = 0;
    T_Errors1=0;
    T_Errors2=0;

    while T_Errors < 100

        uncoded_bits  = round(rand(1,bit_count));

         B1 = uncoded_bits(1:2:end);
        B2 = uncoded_bits(2:2:end);

        a = sqrt(1/10);
        qpsk_sig = (((B1==0).*(B2==0)*(exp(i*pi/4))+(B1==0).*(B2==1)...
            *(exp(3*i*pi/4))+(B1==1).*(B2==1)*(exp(5*i*pi/4))...
            +(B1==1).*(B2==0)*(exp(7*i*pi/4)))); 

        h = sqrt(0.5*((randn(2,length(qpsk_sig))).^2+(randn(2,length(qpsk_sig))).^2));

       n=1/2^(SNR(aa)/2); % Source to  Relay
        n1=1/10^(SNR(aa)/10);  %Relay to Destination

        rx = (qpsk_sig.*h(1,:)) + sqrt(n/2)*(randn(1,length(qpsk_sig))+i*randn(1,length(qpsk_sig)));  % Source to  Relay

         rx1 = 0.7*(rx.*h(2,:))+(0.3*(qpsk_sig.*h(2,:))) + sqrt(n1/2)*(randn(1,length(qpsk_sig))+i*randn(1,length(qpsk_sig)));  %Relay to Destination