<s>
Higher-order	B-Device
modulation	I-Device
is	O
a	O
type	O
of	O
digital	O
modulation	O
usually	O
with	O
an	O
order	O
of	O
4	O
or	O
higher	O
.	O
</s>
<s>
Examples	O
:	O
quadrature	O
phase-shift	B-General_Concept
keying	I-General_Concept
(	O
QPSK	O
)	O
,	O
and	O
m-ary	O
quadrature	B-Device
amplitude	I-Device
modulation	I-Device
(	O
m-QAM	O
)	O
.	O
</s>
