User Manual

Node B Installation Guide
DRAFT
17 July, 2001 IPWireless Proprietary
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5.11 GPS
5.5.1 GPS Operation
The Node B has an integral GPS antenna and receiver, as shown in figure above. The GPS
timing signal is used by the Node B for the TDD frame timing, so that all Node B’s in a network
are synchronized. The GPS signal is also used by the master oscillator for a frequency reference.
The Node B can operate for several hours after a loss of GPS timing but a gradual drift of the
frame timing will result in system interference and a loss of handoff capability.
The GPS receiver is automatically enabled when the Node B is powered and there are no
adjustments or settings to be made by the user.
After installation of the Node B, verify proper operation of the GPS receiver by connecting the
Local Maintenance Terminal (LMT) to the LMT port and accessing typing “gpsstats”.
5.5.3 GPS Repeater Installations
A GPS repeater functions as a reradiating repeater to provide a GPS signal in areas that do not
have a clear view of the sky. The repeater consists of an active antenna, a repeater block, a
passive antenna, connecting cables and a +12VDC supply
The location of the active antenna should be chosen so that the antenna has a clear view of the
sky. A suitable location can be verified before installation by checking for GPS lock with a
handheld GPS unit. The repeater block and passive antenna are installed in the coverage area
(Node B location). The +12VDC supply can be provided by a wall transformer that is connected
to a UPS.
After installation and power-on, verify that the handheld GPS unit is able to obtain GPS lock
inside the Node B installation area. If not, make adjustments to the antenna locations as required
until the handheld GPS receiver can obtain lock. After the Node B is installed, verify that the
Node B GPS receiver is able to obtain and keep GPS lock condition.