16-qam modulation

I have a problem with 16qam modulation. I want to modulate with 16qam a binary signal and as I know 16-qam supposed to separate the signal into groups of 4 bits and maps them each one to a complex number. The problem is that I try to do this with 16 bits but I don't take 4 complex numbers but 16! I give you the code to understand better. Thank you and sorry for my English!

clear all
close all
clc

ip = [1 0 1 0 1 0 1 0]
%------ code ------%
trell = poly2trellis([7],[133 171])
coded = convenc(ip,trell)
%------ 16qam mode ------%
q = modem.qammod(16)
y = modulate (q,coded)
%------ 16qam demode ------%
z = modem.qamdemod(16)
x = demodulate (z,y)
%------ decode ------%
decoded = vitdec(x,trell,5,'trunc','hard')

Answer 1

[Hrasek]

For modem.qammod must be decimal input. You have to use binary decimal converter on the input modem.qammod