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User Manual
Airbridge cBTS3612 CDMA Base Station
EIB (Erasure Indicator Bit) method
l
When the MS adopts EIB power control method, it will detect forward frame quality,
and feed back the information to the BTS via EIB. The BTS will adjust the transmit
power according to EIB information.
Forward quick power control
l
MS will adjust BTS power according to power control bit (the maximum speed can
reach 800bit/s). In cdma2000 1X system, large data service is supported. Therefore,
the requirement on forward power control is increasingly strict. The forward quick
power control method can control forward channel transmit power accurately, so as
to reduce interference and improve the capacity.
2)
Reverse power control
Reverse power control includes open-loop power control and closed-loop power
control. The closed-loop power control can be sub-divided into inner loop power
control and outer loop power control.
Open-loop power control method
l
The MS will determine transmitting power intensity to access the BTS according to
the received pilot signal strength.
Closed-loop power control method
l
The BTS issues power control command to the MS, and performs the adjustment
according to MS feedback. The principle of closed-loop power control is shown in
Figure 4-10.
Power control bit
MS
Figure 4-10 Closed-loop power control
Inner loop power control: the BTS will issue power control bit according to the
received Eb/Nt.
Outer power control: the BSC will adjust Eb/Nt setting value according to the Frame
Error Rate (FER) of the received reverse signal. Then the BTS will use the newly set
Eb/Nt
BTS
Internal loop
FER
BSC
External loop
4-14
System Description
4 System Function
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