# Is there any PN cross correlator implementation for packet detection in Gnuradio? **URL:** \ **Category:** GNU Radio\ **Created:** [April 29, 2013, 8:49am UTC](https://www.ruby-forum.com/t/is-there-any-pn-cross-correlator-implementation-for-packet-detection-in-gnuradio/228582 "2013-04-29T08:49:48Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![Yingjie\_C](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/y/f14d63/32.png) [@Yingjie\_C](https://www.ruby-forum.com/u/Yingjie_C)\ **Post date:** [April 29, 2013, 8:49am UTC](https://www.ruby-forum.com/t/is-there-any-pn-cross-correlator-implementation-for-packet-detection-in-gnuradio/228582/1 "2013-04-29T08:49:48Z")
Hi guys, I noticed that Gnuradio uses schmidl PN correlator for packet detection by defalt, where the 1st copy autocorrelate with 2nd copy in one preamble. I wonder if any PN cross correlator is implemented, which means the received signal is cross correlated with known preamble stored locally. Thank you so much. Best, Kay ---
**Author:** ![Yingjie\_C](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/y/f14d63/32.png) [@Yingjie\_C](https://www.ruby-forum.com/u/Yingjie_C)\ **Post date:** [April 29, 2013, 9:23am UTC](https://www.ruby-forum.com/t/is-there-any-pn-cross-correlator-implementation-for-packet-detection-in-gnuradio/228582/2 "2013-04-29T09:23:43Z")
On Mon, Apr 29, 2013 at 02:48:36PM +0800, Yingjie C. wrote: > I wonder if any PN cross correlator is implemented, which means the received > signal is cross correlated with known preamble stored locally. Thank you so > much. You can either use an FIR (see the filter section) or one of the correlators from the ‘Synchronization’ section. ## MB Karlsruhe Institute of Technology (KIT) Communications Engineering Lab (CEL) Dipl.-Ing. Martin B. Research Associate Kaiserstraße 12 Building 05.01 76131 Karlsruhe Phone: +49 721 608-43790 Fax: +49 721 608-46071 www.cel.kit.edu KIT – University of the State of Baden-Württemberg and National Laboratory of the Helmholtz Association