FPGA Central

Hi All,

PN-sequence and orthogonal sequences (e.g. WH codes) are used for
different purposes.

I understand that, typically, PN-sequences have low auto-correlation
which is good for synchronization but unfortunately have higher cross-
correlation bad for multiple access (like in CDMA case)

On the other hand, orthogonal sequences have low cross correlation
properties (zero in the time synchronized case) but suffer high auto
correlation.

Since PN sequence can be easily generated. Can one generate a near
orthogonal pn-sequence(s) for a given LSFR with polynomial? Just for
sake of discussion, take an example as 256 sample PN sequence
generated using polynomial says X^8+X^6+X^5+X^4+1.

How can we generate a near orthogonal sequence from this original PN
sequence?


Any ideas will be very much appreciated.

Thank you

Best,
Sutter

[email protected] wrote:

> Hi All,
>
> PN-sequence and orthogonal sequences (e.g. WH codes) are used for
> different purposes.

[...]

> How can we generate a near orthogonal sequence from this original PN
> sequence?

P. Fan, M. Darnell. “Sequence design for communications applications”
ISBN 0-471-96557


Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com