function SymQAM=tx_16QAM_mod(BitTx)

% Input:  BitTx(1,N_Num)               Output:  SymQAM(1,Carrier_Num*OFDM_Symbol)

N_Num=length(BitTx);
SymQAMtmp=reshape(BitTx,4,N_Num/4).';
SymQAMtmptmp=bi2de(SymQAMtmp,2,'left-msb');
% 0000->3+3i,0001->1+3i,0010->-1+3i,0011->-3+3i,
% 0100->3+i,0101->1+i,0110->-1+i,0111->-3+i,
% 1000->3-i,1001->1-i,1010->-1-i,1011->-3-i,
% 1100->3-3i,1101->1-3i,1110->-1-3i,1111->-3-3i
QAMTable=[3+3i,1+3i,-1+3i,-3+3i,3+i,1+i,-1+i,-3+i,3-i,1-i,-1-i,-3-i,3-3i,1-3i,-1-3i,-3-3i];
SymQAM=QAMTable(SymQAMtmptmp+1);