 
| PN Sequences - Part 2
How PN Codes are used in IS-95 CDMA Systems
By Dr. Ernest Simo

2.0 Using the Long PN Code

How the Long PN Code is Used
The 4.4 trillion chip long Long PN Code is truncated into billions of starting-offsets
where adjacent offsets are separated by 64 chips or multiples of 64 chips.
On the Reverse Link, Long PN Offsets are assigned to Mobile Units on a dedicated basis.
Used as such, they provide isolation between handsets due to their relatively small
cross-correlation factor.
On the Reverse Link, the Long Code is also used in the Data Burst Randomizer Algorithm in order
to determine the position of active Power Control groups within a Frame.
On the Forward Link, the Long Code is also used for the following purposes:
Scramble
the Paging and Traffic Channels
Determine the position of Power Control bits
 CODE: AN INTRODUCTION By Dr. Ernest Simo © 1999 DR. ERNEST SIMO - SPACE2000 |
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