User's Manual

Appendix B: PN Offset Programming Information
May 2000
B-1
SC 4812T CDMA BTS Optimization/ATP
PN Offset Background
All channel elements transmitted from a BTS in a particular 1.25 MHz
CDMA channel are orthonogonally spread by 1 of 64 possible Walsh
code functions; additionally, they are also spread by a quadrature pair of
PN sequences unique to each sector.
Overall, the mobile uses this to differentiate multiple signals transmitted
from the same BTS (and surrounding BTS) sectors, and to synchronize
to the next strongest sector.
The PN offset per sector is stored on the BBX2s, where the
corresponding I & Q registers reside.
The PN offset values are determined on a per BTS/per sector(antenna)
basis as determined by the appropriate cdf file content. A breakdown of
this information is found in Table B-1.
PN Offset Usage
Only the 14–chip delay is currently in use. It is important to determine
the RF chip delay to be able to test the BTS functionality. This can be
done by ascertaining if the CDF file
FineTxAdj value was set to “on”
when the MCC was downloaded with “image data”. The
FineTxAdj
value is used to compensate for the processing delay (approximately
20 S) in the BTS using any type of mobile meeting IS–97
specifications.
If the
FineTxAdj value in the cdf file is 213 (D5 HEX), FineTxAdj has
been set for the 14 chip table.
CDF file I and Q values can be represented in DECIMAL
or HEX. If using HEX, add 0x before the HEX value. If
necessary, convert HEX values in Table B-1 to decimal
before comparing them to cdf file I & Q value assignments.
IMPORTANT
*
B