User's Manual

Advanced RF Technologies, Inc.
64
- The attenuation and DL output ALC level for the other ports are set based on the formula below
to keep the power ratio between BCU ports.
! The maximum output power for the specified path = 10*log10[10^(Max_ALC/10)x(Pwr_Ratio)/
Max_Ratio]
 Max_ALC: DL output ALC level for the path with maximum power ratio = 5dBm
 Pwr_Ratio: Targeted DL output power ratio value for the specified path
 Max_Ratio: maximum power ratio value
! The attenuation for the specified path = The targeted maximum input power for the specified path -
The maximum output power for the specified path
! DL output ALC level = The targeted maximum input power for the specified path - The attenuation
for the specified path
! The path for AT&T- CH2
 The maximum output power = 10*log10[10^(5/10)x20%/50%] = 1.02dBm
 The ATT value = 18.0dBm-1.02dBm=16.98dB Î 16.5dB(the control step of used attenuator is
0.5dB)
 DL output ALC level = 18dBm – 16.5dB = 1.5dBm
! The path for Sprint- CH1
 The maximum output power = 10*log10[10^(5/10)x30%/50%] = 2.78dBm
 The ATT value = 9.0dBm-2.78dBm=6.22dB Î 6.0dB(the control step of used attenuator is 0.5dB)
 DL output ALC level = 9.0dBm – 6.0dB = 3.0dBm
- The DL maximum output power of BCU is the sum of maximum output power for each port and
this power becomes the HE RFU input commissioning level.
- The maximum input level of HE RFU should be less than 10dBm (= 5dBm + 10*log10 (3)) because
the maximum output of BCU per each path doesn’t exceed 5dBm by ALC function.
Table 7-10 Maximum Output Power per carrier
WSP Sprint AT&T VZW
Targeted maximum input power
9.0dBm
18.0dBm
11.0dBm
19.2dBm
Targeted DL Output Power Ratio set by user 30.0% 20.0% 50.0%
DL maximum output power
(ATT control step, 0.5dB is not considered)
2.78dBm 1.02dBm 5.0dBm
ATT value
6.0dB
16.5dB
6.0dB
DL output ALC level or
DL Maximum output power
(ATT control step, 0.5dB is considered)
3.0dBm
1.5dBm
5.0dBm
8.2dBm(RFU DL Input commissioning level)
DL Output Power Ratio
considering ATT control step 0.5dB
30.37% 21.50% 48.13%