# Why other correlators(ml or pnac) can not work in ofdm example except for Schmidl and Cox correlator **URL:** \ **Category:** GNU Radio\ **Created:** [May 2, 2013, 10:54am UTC](https://www.ruby-forum.com/t/why-other-correlators-ml-or-pnac-can-not-work-in-ofdm-example-except-for-schmidl-and-cox-correlator/228661 "2013-05-02T10:54:11Z")\ **Posts on this page:** 4\ **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:** [May 2, 2013, 10:54am UTC](https://www.ruby-forum.com/t/why-other-correlators-ml-or-pnac-can-not-work-in-ofdm-example-except-for-schmidl-and-cox-correlator/228661/1 "2013-05-02T10:54:11Z")
HI guy, I have checked the code in ofdm\_receiver.py and found that gnuradio uses Schmidl and Cox as default correlator for frame detection. However, when I change to other correlators like\* ml or pnac\*,the receiver cannot receiver any more. Is there any problem with that? Thanks 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:** [May 2, 2013, 11:05am UTC](https://www.ruby-forum.com/t/why-other-correlators-ml-or-pnac-can-not-work-in-ofdm-example-except-for-schmidl-and-cox-correlator/228661/2 "2013-05-02T11:05:17Z")
On Thu, May 02, 2013 at 04:52:53PM +0800, Yingjie C. wrote: > I have checked the code in ofdm\_receiver.py and found that gnuradio uses > Schmidl and Cox as default correlator for frame detection. However, when I > change to other correlators like ml or pnac,the receiver cannot receiver any > more. Is there any problem with that? Thanks so much. The OFDM code is under heavy maintenance right now. The code you’re inspecting is a bit outdated and it’s quite likely it doesn’t work properly. 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 ---
**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:** [May 2, 2013, 11:10am UTC](https://www.ruby-forum.com/t/why-other-correlators-ml-or-pnac-can-not-work-in-ofdm-example-except-for-schmidl-and-cox-correlator/228661/3 "2013-05-02T11:10:33Z")
Thanks for you reply. Can you tell me what should I do next? Update the code or other things? Cause I am very urgent with my project and need to use other correlator(like pnac). Thanks in advance. 2013/5/2 Martin B. (CEL) [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) ---
**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:** [May 3, 2013, 7:42pm UTC](https://www.ruby-forum.com/t/why-other-correlators-ml-or-pnac-can-not-work-in-ofdm-example-except-for-schmidl-and-cox-correlator/228661/4 "2013-05-03T19:42:45Z")
Hi Yingjie C. - If your schedule requires that the code work, then feel free to hack on it and make it work! That’s the beauty of open source. You could then contribute your code back to the community, thus helping everyone that has put effort into making GNURadio what it is, today =) Cheers, Ben