User Manual

UBS Macro B T S Product Ov erview Chapter 1: Ov erview

DMI (Digital Module Internal) module

The DMI contains two main components: a controller board and at least one modem board (i.e.,

1X CDMA or EV -DO). The controller board provides interfaces for up to two modem boards (i.e.,

1X CDMA, EV -DO , or a combination of both). A DMI can be upgraded with a second modem

board depending upon the conﬁguration required at the BTS .

In the forward direction (BTS to Mobile), the DMI terminates the backhaul control and bearer

connections from the S SI, processes the bearer and control data then routes the baseband

data to the XMI for conversion/RF modulation and transmission over the air interface to the

subscriber .

In the reverse direction (Mobile to BTS), the XMI receives the subscriber transmission over

the air interface. The XMI demodulates the received RF signal and converts it to baseband

data. The received baseband data is routed to the DMI for processing and generation to the

associated control and bearer data for transmission to the network via the S SI.

External interfaces on the DMI include the following:

• +27 V DC (nominal) power input

• T wo S SI interfaces

• T wo XMI interfaces

The controller board provides all of the DMI external interfaces as well as interfaces for two

modem boards. The controller is made up of the following functions: Site Processor (SPROC),

Synchronization, Interworking (protocol termination), DMI baseband processing, XMI interfaces

and S SI interface.

The DMI controller board also contains an Oven Controlled Crystal Oscillator (OCX O) that

is synchronized to the BTS system timing established/sourced by the E -GPS or Remote GPS

(RGPS) head. The OCX O also provides the MSO function. In the event that the GPS system

timing signal (i.e., E -GPS or RGPS or sync -sharing) is lost, the DMI controller can select the

MSO as a backup synchronization source for maintaining BTS system timing for up to 8 hours

PDU (Power Distribution Unit)

The PDU is the central power distribution point for the UBS Macro BTS frame. It contains input

power feeds that connect to the +27 V DC power output of one of the following:

• Optional –48 V DC PSM (P ower Supply Module) shelf

• Optional 220 V AC PSM shelf

• Customer supplied external +27 V DC power source

The PDU houses circuit breakers/power connectors for +27 V DC power distribution to each of

the following UBS Macro BTS frame subsystems:

• XMIs

• DMIs

• S SIs

• Accessories

The PDU also contains bulk capacitance to stabilize the internal bus voltage to facilitate

subsystem hot -swap and absorb surge energy .

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FOA SEP 2007