> Hi all,
> there always said long PN sequence(period 2^n-1) got a small
> cross-correlation property as -1/(2^n-1). But in practice, one symbol
> could only be spread by a small amount(128 etc) but not 2^n-1, so how
> can we guarantee the cross correlation property -1/(2^n-1)? Thanks.
You can't. The level of noise from other transmitter's PN-modulated
traffic can be high, which is why there are layers of synchronous
demodulation and error correction after the first despreading.
--
http://www.wescottdesign.com
Reply by Laron●September 9, 20092009-09-09
Hi all,
there always said long PN sequence(period 2^n-1) got a small
cross-correlation property as -1/(2^n-1). But in practice, one symbol
could only be spread by a small amount(128 etc) but not 2^n-1, so how can
we guarantee the cross correlation property -1/(2^n-1)? Thanks.
B. R.
Laron