Information Technology Reference
In-Depth Information
Since users access the spectrum with the same power level and the interference
relationship and distance measurement are symmetry, we know that
P
k
d
−
ʱ
kn
P
k
d
−
ʱ
kn
P
n
d
−
ʱ
=
=
nk
.
(4.17)
p
n
p
k
p
k
n
=
k
k
∈
N
n
∈
N
n
∈
N
Combining (
4.16
) and (
4.17
), we have that
1
2
1
2
ʦ
1
(
a
)
P
m
d
−
ʱ
P
n
d
−
ʱ
ˉ
k
−
ʦ
1
(
a
)
=−
mk
I
{
a
k
=
a
m
}
−
nk
I
{
a
n
=
a
k
}
−
a
k
p
k
p
k
m
∈
N
n
∈
N
1
2
1
2
P
m
d
−
ʱ
P
n
d
−
ʱ
ˉ
a
k
+
mk
I
{
a
k
=
a
m
}
+
nk
I
{
a
n
=
a
k
}
+
p
k
p
k
m
∈
N
n
∈
N
P
m
d
−
ʱ
ˉ
k
P
m
d
−
ʱ
ˉ
a
k
=−
mk
I
{
a
k
=
a
m
}
−
a
k
+
mk
I
{
a
k
=
a
m
}
+
p
k
p
k
m
∈
N
m
∈
N
ʳ
k
(
a
)
U
k
(
a
)
=−
+
ʳ
k
(
a
)
=
−
U
k
(
a
)
.
(4.18)
Similarly, for the part
ʦ
2
, we have that
w
kn
ʦ
2
(
a
)
P
k
d
−
ʱ
P
k
d
−
ʱ
−
ʦ
2
(
a
)
=
−
kn
I
{
a
n
=
a
k
}
+
kn
I
{
a
n
=
a
k
}
sp
k
n
∈
N
=
w
kn
×
sp
k
n
∈
N
⊛
⊝
−
P
k
d
−
ʱ
P
m
d
−
ʱ
ˉ
a
n
kn
I
{
a
n
=
a
k
}
−
mn
I
{
a
n
=
a
m
}
−
m
=
k
p
n
m
∈
N
⊞
P
k
d
−
ʱ
⊠
P
m
d
−
ʱ
ˉ
a
n
+
kn
I
{
a
n
=
a
k
}
+
mn
I
{
a
n
=
a
m
}
+
p
n
m
=
k
m
∈
N
w
kn
+
ʳ
n
(
a
)
−
ʳ
n
(
a
)
=
sp
k
n
∈
N
w
kn
U
n
(
a
)
U
n
(
a
)
.
=
−
(4.19)
sp
k
n
∈
N
Finally, substituting (
4.18
) and (
4.19
) into (
4.15
), we obtain that
w
kn
U
n
(
a
)
−
U
n
(
a
)
.
ʦ
(
a
)
=
U
k
(
a
)
−
ʦ
(
a
)
−
U
k
(
a
)
+
(4.20)
sp
k
n
∈
N
sp
k
, we have that
k
Since user
k
can not generate interference to any user
n
∈
N
\
N
U
n
(
a
)
sp
k
.
s
=
U
n
(
a
),
∀
n
∈
N
k
\
N
