RRU3936
Hardware Description
2 RRU Introduction
RRU Introduction
About This Chapter
This chapter describes the exterior and function of the RRU as well as the ports and indicators
on the RRU.
2.1 RRU Exterior
This section describes the exterior and dimensions of an RRU.
2.2 RRU Functions
This section describes the main functions of the RRU.
2.3 RRU Technical Specifications
This section describes technical specifications of an RRU, including supported modes, frequency
bands, RF specifications, engineering specifications, and antenna capabilities.
2.4 RRU Ports
This section describes ports on the RRU panels. An RRU has a bottom panel, cabling cavity
panel, and indicator panel.
2.5 RRU Indicators
This section describes six indicators on an RRU. They indicate the running status.
2.6 Optical Modules
An optical module transmits optical signals between an optical port and a fiber optic cable.
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2.1 RRU Exterior
This section describes the exterior and dimensions of an RRU.
Figure 2-1 shows an RRU.
Figure 2-1 RRU exterior
Figure 2-2 shows RRU dimensions.
Figure 2-2 RRU dimensions
2.2 RRU Functions
This section describes the main functions of the RRU.
The Remote Radio Unit (RRU) consists of the high-speed interface unit, signal processing unit,
power amplifier, duplexer, extension ports, and power module. Figure 2-3 shows the function
structure of the RRU.
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Figure 2-3 Function structure of the RRU
NOTE
For details about the extension ports, see 2.4 RRU Ports.
The RRU performs the following functions:
l
Receives downlink baseband data from the BBU and sends uplink baseband data to the
BBU.
Receives RF signals from the antenna system, down-converts the signals to intermediate
frequency (IF) signals, amplifies the IF signals, and performs analog-to-digital conversion.
The transmit (TX) channel filters downlink signals, performs digital-to-analog conversion,
and up-converts RF signals to the TX band.
Multiplexes receive (RX) and TX signals on the RF channel, which enables these signals
to share the same antenna path. It also filters the RX and TX signals.
Provides a built-in Bias Tee (BT). The built-in BT couples RF signals and OOK signals
and transmits them through the TX/RX port A. The built-in BT also supplies power to the
tower mounted amplifier (TMA).
The RRU can be powered by the AC/DC power module. In this case, this RRU is called
AC RRU. For details about the AC/DC power module, see the AC/DC Power Module User
Guide or OPM15M User Guide.
2.3 RRU Technical Specifications
This section describes technical specifications of an RRU, including supported modes, frequency
bands, RF specifications, engineering specifications, and antenna capabilities.
For details about technical specifications of an RRU, see section "Technical Specifications of
RRUs" in the 3900 Series Base Station Technical Description.
2.4 RRU Ports
This section describes ports on the RRU panels. An RRU has a bottom panel, cabling cavity
panel, and indicator panel.
Figure 2-4 shows the ports on the RRU panels.
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Figure 2-4 Ports on the RRU panels
Table 2-1 describes ports and indicators on the RRU panels.
Table 2-1 Ports and indicators on the RRU panels
Item
Silkscreen
Remarks
(1) Ports in the cabling
cavity
RTN(+)
Power supply socket
(2) Ports at the bottom
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NEG(-)
CPRI0
Optical/electrical port 0, connected to the
BBU
CPRI1
Optical/electrical port 1, connected to the
BBU
ANT_TX/RXA
TX/RX port A, supporting RET signal
transmission
ANT_RXB
RX port B
RX_IN/OUT
Interconnection port, used for RRU
interconnection
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Item
(3) Indicators
Silkscreen
Remarks
EXT_ALM
Alarm monitoring port used for monitoring
one RS485 signal and two dry contact signals
RET
Communication port for the RET antenna,
supporting RET signal transmission
RUN
See 2.5 RRU Indicators.
ALM
ACT
VSWR
CPRI0
CPRI1
NOTE
l The port for transmitting RET signals is determined by the software.
l Conect the CPRI0 port to the BBU by default in the single-mode scenario.
2.5 RRU Indicators
This section describes six indicators on an RRU. They indicate the running status.
For detailed positions of RRU indicators, see 2.4 RRU Ports.
Table 2-2 describes RRU indicators.
Table 2-2 RRU indicators
Indicator
Color
Status
Meaning
RUN
Green
Steady on
There is power supply, but the module is
faulty.
Steady off
There is no power supply, or the module is
faulty.
Blinking (on for
1s and off for 1s)
The board is functioning properly.
Blinking (on for
0.125s and off for
0.125s)
Software is being loaded to the module, or
the module is not started.
Steady on
Alarms are generated, and the module must
be replaced.
ALM
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Red
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Indicator
ACT
VSWR
CPRI0
CPRI1
Color
Green
Red
Red or
green
Red or
green
Status
Meaning
Blinking (on for
1s and off for 1s)
Alarms are generated. The alarms may be
caused by the faults on the related boards or
ports. Therefore, you need to locate the fault
before deciding whether to replace the
module.
Steady off
No alarm is generated.
Steady on
The module is running properly with TX
channels enabled or the software is being
loaded without RRU running.
Blinking (on for
1s and off for 1s)
The module is running properly with TX
channels disabled.
Steady off
No Voltage Standing Wave Ratio (VSWR)
alarm is generated.
Steady on
VSWR alarms are generated.
Steady green
The CPRI link is functioning properly.
Steady red
An optical module fails to transmit or receive
signals because the optical module is faulty
or the fiber optic cable is broken.
Blinking red (on
for 1s and off for
1s)
The CPRI link is out of lock because of a
failure in clock lock between two modes or
mismatched data rates over CPRI ports.
Steady off
The optical module cannot be detected, or the
optical module is powered off.
Steady green
The CPRI link is functioning properly.
Steady red
An optical module fails to transmit or receive
signals because the optical module is faulty
or the fiber optic cable is broken.
Blinking red (on
for 1s and off for
1s)
The CPRI link is out of lock because of a
failure in clock lock between two modes or
mismatched data rates over CPRI ports.
Steady off
The optical module cannot be detected, or the
optical module is powered off.
2.6 Optical Modules
An optical module transmits optical signals between an optical port and a fiber optic cable.
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NOTE
The exteriors of an optical module and the label on an optical module in this section are for reference only.
The actual exteriors may be different.
Exterior
The following figure shows the exterior of an optical module.
Figure 2-5 Exterior of an optical module
Label on an optical module
There is a label on each optical module, which provides information such as the rate, wavelength,
and transmission mode, as shown in the following figure.
Figure 2-6 Label on an optical module
(1) Rate
(2) Wavelength
(3) Transmission mode
Optical Module Type
Optical modules can be divided into single- and multimode optical modules, which can be
distinguished as follows:
l
The puller of a single-mode optical module is blue and the puller of a multimode optical
module is black or gray.
The transmission mode is displayed as "SM" on the label of a single-mode optical module
and "MM" on the label of a multimode optical module.
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