News





Join the CDMAonline Mailing List


Enter your email address above,
then click 'Sign Up'.

CDMA Interactive




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
BACK CONTENTS INDEX GLOSSARY NEXT BACK CONTENTS INDEX GLOSSARY NEXT