User Manual

Chapter 2 - Installation Installing the Base Transceiver Station (BTS) Equipment
4Motion 75 System Manual
2.3.3.2 Power Calculation Example
Configuration: A 2.x GHz BTS with 3 AU cards and 4 1x1 ODUs connected to each
AU. Uplink-Downlink split (allocation ratio) of 12-34.
Maximum power consumption that should be supplied by PSUs:
NPU: 68W
3 AUs: 3*74=222W
AVU: 40W
GPS Receiver: 6w
Total maximum power supplied by PSUs: 336W
Total maximum power required excluding ODUs: 336/0.8 (PSUs Efficiency) + 35
(PIU) = 455W
When calculating the power requirements associated with the ODUs, we should
distinguish between the peak power consumption (maximum current during Tx)
and the average power consumption (taking into account Tx/Rx split ratio) that
affect the requirements from a backup power source.
For a 2.x GHz system, the peak power consumption of 12 ODUs under worst
conditions is 12*89 = 1068W. Thus, the maximum peak power of the system is
455 + 1068 = 1523W (37.6A @ -40.5 VDC).
The maximum average power consumption of each ODU, assuming UL-DL
(Rx/Tx) ratio of 12-34 is (15*12+89*34)/46 = 70W. Thus, the maximum average
power required for the whole system is 455 + 70*12 = 1295W (32A @ -40.5 VDC).
2.3.3.3 Power Feeders Requirements
According to required configuration, each AU can be connected to one, two, or
four 1x1 ODUs. It may also be connected to either one or two 2x1 ODUs: A 4x2
ODU is treated and functions as two independent 2x1 ODUs. The two 2x1 ODUs
that form a 4x2 ODU are powered via the TX/Rx Ports (Ports 1 and 3).
Once an ODU Feeder is installed, all 4 channels should be used.
Power Feeders are required in the following configurations:
Table 2-8: Power Feeder Requirements
Configuration Number of Power Feeders
5 AUs, each AU connected to four 1x1 ODUs 1