function result = send(input,snr);
 
%       Let the data symbol through the channel with JD in the receive side. 
%    Spreading, frame, channel, channel estimate, JD, despread,deframe.
%    Note that in this function, many parameters should have been saved in
%    the global variable 'sim_consts'. 

    global sim_consts;
        
    cNumber = sim_consts.cNumber;
    tsNumber = sim_consts.tsNumber;
    ka=sim_consts.ka;
    w = sim_consts.W ;
    sim_consts.gu = zeros(ka,w);
 
    
    result = [];
%    s = 2*randint(1,44*cNumber*tsNumber)-1 + i * (2*randint(1,44*cNumber*tsNumber)-1);
%    snr = 2 ;
    s= input.';
    for tsIdx = 1:tsNumber
        ss = s((tsIdx-1)*cNumber*44+1:tsIdx*cNumber*44);
        for kk = 1:cNumber
            sc(kk,:) = ss((kk-1)*44+1:kk*44);
        end
        
        if sim_consts.cDisturb == 1
            for kk = cNumber+1:sim_consts.cAvailable
                sc(kk,:) = 2*randint(1,44)-1 + i * (2*randint(1,44)-1);
            end
        end
        
        sp = zeros(cNumber,864);
        for kk = 1:size(sc,1)
            temp = sc(kk,:).'*ovsf(kk);
            for idx = 1:22
                sp(kk,(idx-1)*16+1:idx*16) = temp(idx,:);
            end
            for idx = 23:44
                sp(kk,(idx-23)*16+1+496:(idx-22)*16+496) = temp(idx,:);
            end        
        end    
        
        send((tsIdx-1)*864+1:tsIdx*864) = sum(sp)';
        send((tsIdx-1)*864+353:(tsIdx-1)*864+480)    = cNumber*midamble_1';
    end
    
    for kk = 1:ka
        sim_consts.hsig(kk, :) =  Rayleigh_Doppler_multiPath(...
            sim_consts.fc,              ...
            sim_consts.v,               ...
            sim_consts.startT,          ...
            sim_consts.endT,            ...
            sim_consts.deltaT,          ...
            sim_consts.chipRate,        ...
            sim_consts.nsdelay,         ...
            sim_consts.averagePower );    % child function , type 'help Rayleigh_Doppler_multiPath' for detail
    end
    
    for idx = 1:ka
        tt(idx,:) = send.*abs(sim_consts.hsig(idx,:));
        for tsIdx = 1:tsNumber
            power=0;
            for kk=1:864
                tempp=tt(idx,(tsIdx-1)*864+kk);
                power=power+tempp*tempp';
            end;
            power_s = power/864;
            tempp=10^(snr/10);
            sigma=sqrt(power_s/tempp);
            tt(idx,(tsIdx-1)*864+1:tsIdx*864) = tt(idx,(tsIdx-1)*864+1:tsIdx*864) + normrnd(0,sigma,1,864) + j*normrnd(0,sigma,1,864);
        end
    end
    
    a_1 = a_mid_1;
    b_1 = inv(a_1'*a_1)*a_1';
    for tsIdx = 1:tsNumber
        for idx = 1:ka
            t(idx,:) = tt(idx,(tsIdx-1)*864+1:tsIdx*864);
        end
        
        for idx = 1:ka
            rm(idx,:) = t(idx,353:(480+w-1));
        end
        
        ry1 = zeros(ka,352+w-1);
        for idx = 1:ka
            ry1(idx,:)=t(idx,1:352+w-1);
        end
        y1 = [];
        for idx = 1:ka
            y1 = [y1 ry1(idx,:)];
        end
        y1 = y1';
        
        ry2 = zeros(ka,352+w-1);
        for idx = 1:ka
            ry2(idx,:)=t(idx,497:848+w-1);        
        end
        y2 = [];
        for idx = 1:ka
            y2 = [y2 ry2(idx,:)];
        end
        y2 = y2';
                
        for idx = 1:ka
            sim_consts.gu(idx,:)=(b_1*rm(idx,:)')';
        end
        
        a= A_gen_1;
        h=a'*a;
        digh=diag(diag(h));
        dighinv=inv(digh);
        mt=chol(h);
        hinv=inv(mt);
        htinv=inv(mt');
        s_zf1=hinv*htinv*digh*dighinv*a'*y1;
        s_zf2=hinv*htinv*digh*dighinv*a'*y2;
        
        rs = zeros(cNumber,44);
        for kk = 1:22
            for ii = 1:cNumber
                rs(ii,kk) = s_zf1(cNumber*(kk-1)+ii);
                rs(ii,kk+22) = s_zf2(cNumber*(kk-1)+ii);
            end
        end        
        
        for kk = 1:cNumber
            result = [result rs(kk,:)];
        end 
        clear t idx rm ry1 y1 ry2 y2 a h mt digh dighinv hinv htinv s_zf1 s_zf2 rs kk ii ;
    end   
    
    result = 2*(real(result)>0)-1 + j*(2*(imag(result)>0)-1);
%    sum((s-result)~=0)/size(s,2)

    clear ka snr sp1 sp2 sp send sigma idx ss sc tt tsIdx temp ...
        t rm ry1 ry2 a_1 b_1 a w h digh dighinv mt hinv htinv s_zf1...
        rs1 rs2 ddss i kk power power_s s1 s2 x y1 y2 s_zf2 tempp cNumber tsNumber;