Information Technology Reference
In-Depth Information
⎛
⎞
E
⎜
⎜
⎝
b
⎟
⎟
⎠
⋅
∂
⋅
N
VF
N
0
η
=
(10)
⎛
⎞
E
⎜
⎜
⎝
b
⎟
⎟
⎠
⋅
∂
+
G
VF
N
0
η
=
100
%
Network limit capacity is 100% load, that is
. According to the
Equation (10), Equation (11) can be obtained.
G
N
=
1
+
⎛
⎞
E
(11)
⎜
⎜
⎝
b
⎟
⎟
⎠
⋅
∂
VF
N
0
Equation (11) is important, the physical meaning can be demonstrated. When the
number of users in a single cell will reach the limit capacity, high noise-rise[6][8]
makes it difficult that BS(base station) demodulate the signal come from user. Thus
the power control algorithm requires increasing transmitting power for each user.
Whereas transmitting power increase of each user further improve the noise-rise. That
is, the rate of single-user power-rise is lower than the rate of noise-rise since multi-
users have increased transmitting power. So
E
b
of demodulating the service
will not become better due to single-user increasing transmitting power, but will be
even worse [7]. It is cycled so as to power of MS (mobile station) reach to infinitely
high. However, mobile station power is always limited in reality, inconstant noise-rise
makes the mobile station power exhaust and still be unable to meet the
/
N
0
E
b
/
N
0
requirements [9].
3 Uplink Multiple Cells Capacity Analysis and Research
In multiple cells conditions, to any cell, interference not only comes from self-cell,
but also comes from adjacent cells .Some relevant parameters are as follows:
I
is intra-interference.
othe
I
is inter-interference.
F
is actor of interference ratio. It can be defined
own
I
F
=
other
I
(12)
I
+
own
other
That is, in multiple cells, the base station receives the total interference power of
1
multiple cells is more than single cell
times, and the capacity of multiple cells
1
−
F
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