User Manual

ADCP-75-192 • Issue D • October 2005 • Section 7: Autonomous Software Functionality
Page 7-2
 2005, ADC Telecommunications, Inc.
3 REVERSE GAIN MANAGEMENT
The Digivance CXD system autolimits any strong in-band signal which reaches the RAN at a
peak input level of -40 dBm relative to the antenna port. The process does this by
continuously monitoring digital input at the FPGA adding attenuation at the RDC if the
threshold is reached. This “AGC event” is logged on the CPU running the RDC process.
Attenuation is backed out as the signal strength subsides.
In all other cases, Reverse Gain Management is a static process in the Digivance CXD
software where the reverse path gain is balanced to match the Reverse Gain parameter set in
the Tenant OAM MIB (see Tenant Configuration section of this document). This balancing is
accomplished solely by Tenant Processing by using the constant gain factors of the reverse
path modules to adjust the BIM attenuators such that the Reverse Gain (minus the Reverse
Cable Loss) is achieved.
4 FORWARD DELAY MANAGEMENT
Forward Delay Management (FDM) is a software function that is part of Tenant Processing
and whose responsibility is to equalize the forward path delays to all RAN’s in a simulcast
group. The FDM process is run each time a RAN is added or removed from the simulcast
group, if the FDM process is "enabled" in the Tenant OAM MIB (see Tenant Configuration
section of this document). The FDM process algorithm is as follows:
Start with Forward Base Delay Target configured in the Tenant OAM MIB (See Tenant
Configuration section of this document).
Set the delay value in the RAN SIF’s to make them equal to the base delay plus some delay
skew based on the RAN ID.
The amount of delay skew is based on the Forward Delay Skew configured in the Tenant
OAM MIB (See Tenant Configuration section of this document) and the RAN ID using the
following:
Total Delay = Base delay + (delay skew X(RAN ID -1)).
5 REVERSE DELAY MANAGEMENT
Reverse Delay Management (RDM) is a software function that is part of Tenant Processing
and whose responsibility is to equalize the reverse path delays from all RAN’s in a simulcast
group. The RDM process is run each time a RAN is added or removed from the simulcast
group, if the RDM process is "enabled" in the Tenant OAM MIB (see Tenant Configuration
section of this document). The RDM process algorithm is as follows:
Start with Reverse Base Delay Target configured in the Tenant OAM MIB (See Tenant
Configuration section of this document).