Cryptography Reference
In-Depth Information
Figure 2.6 - Constellation of the 32-QAM modulation.
of a modulation combining phase and amplitude for
M
=16(
M
1
=4
,M
2
=4)
.
Figure 2.7 - Constellation of a modulation combining phase and amplitude for
M
=16
.
The average energy
E
s
to transmit the pair
(
A
j
,A
j
)
, that is, a group of
log
2
(
M
)
binary data, is equal to:
T
E
V
j
cos
2
(2
πf
0
t
+
ϕ
0
+
φ
j
)
dt
E
s
=
(2.25)
0
For a group of data of even length
m
,E
V
j
=2
A
2
(
M
−
1)
/
3
and thus, for
f
0
>>
1
/T
, the average energy
E
s
is equal to:
E
s
=
A
2
T
M
−
1
(2.26)
3
The average energy used to transmit a bit is
E
b
=
E
s
/
log
2
(
M
)
.
