User Manual

Appendix E: PN Offset Programming Information

Jan 2002

E-1

SC4812ET BTS Optimization/ATP — CDMA LMF

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 BBXs, 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 E-1.

PN Offset Usage

There are three basic RF chip delays currently in use. It is important to

determine what RF chip delay is valid 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 mS) in the BTS using any type of

mobile meeting IS–97 specifications.

Observe the following guidelines:

 If the FineTxAdj value in the cdf file is 101 (65 HEX), the

FineTxAdj has not been set. The I and Q values from the 0 table

MUST be used.

If the

FineTxAdj value in the cdf file is 213 (D5 HEX), FineTxAdj has

been set for the 14 chip table.

 If the FineTxAdj value in the cdf file is 197 (C5 HEX), FineTxAdj

has been set for the 13 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 E-1 to decimal

before comparing them to cdf file I & Q value assignments.

IMPORTANT

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