function [out]=de_qpsk_mapping_plcp(datain,length);
for i=1:length
    if(real(datain(i))>=0)
    temp((i-1)*2+1)=1;
    else
    temp((i-1)*2+1)=0;
    end
    if(imag(datain(i))>=0);
    temp((i-1)*2+2)=1;
    else
    temp((i-1)*2+2)=0;
    end
end
out=temp;