# Proposal for GSoC on gr-gsm **URL:** \ **Category:** GNU Radio\ **Created:** [March 11, 2014, 4:41am UTC](https://www.ruby-forum.com/t/proposal-for-gsoc-on-gr-gsm/239700 "2014-03-11T04:41:36Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![musicdenotation](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ea666f/32.png) [@musicdenotation](https://www.ruby-forum.com/u/musicdenotation)\ **Post date:** [March 11, 2014, 4:41am UTC](https://www.ruby-forum.com/t/proposal-for-gsoc-on-gr-gsm/239700/1 "2014-03-11T04:41:36Z")
Hi all, As Martin B. noticed in the mail list yesterday, I haven’t open my proposal here. Here is the link: > **[GitHub - hzhua/grgsm\_proposal: Proposal for GSoC 2014 on gr-gsm](https://github.com/hzhua/grgsm_proposal)** > > Proposal for GSoC 2014 on gr-gsm. Contribute to hzhua/grgsm\_proposal development by creating an account on GitHub. If you have any suggestions, please don’t be hesitate to contact me. Thanks to Sylvain M. for his help on reviewing my first draft. Thanks to Piot Krysik for his suggestions on gr-gsm. Best wishes, Zhenhua ---
**Author:** ![zhenhua\_han](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/z/d2c977/32.png) [@zhenhua\_han](https://www.ruby-forum.com/u/zhenhua_han)\ **Post date:** [March 11, 2014, 8:35am UTC](https://www.ruby-forum.com/t/proposal-for-gsoc-on-gr-gsm/239700/2 "2014-03-11T08:35:19Z")
Hi Zhenhua, gr-gsm should be a good project for you and for the community. I wish you success. You may want to look at the slow frequency hopping implementation of airprobe that is placed here: [https://github.com/BogdanDIA/airprobe-hopping](https://github.com/BogdanDIA/airprobe-hopping). It uses PFB to split a 20mhz band received with USRP-N210 into GSM channels and then use all of them according to the hopping algorithm decoded on the Immediate Assignment message and SI 1. It is not a perfect implementation as airprobe is not perfect too, that is why I think this will be a good project. The hopping patch has been done two years ago and has API for gnuradio3.6 era. I did not update it yet on 3.7. Here is small paper I wrote at the moment of creating a patch. It may be of help to you. > **[Evaluating\_GSM\_hopping\_V1.1.pdf](https://yo3iiu.ro/blog/wp-content/uploads/2012/04/Evaluating_GSM_hopping_V1.1.pdf)** > > 592.64 KB Bogdan On Tuesday, March 11, 2014 5:40 AM, zhenhua han [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: Hi all, As Martin B. noticed in the mail list yesterday, I haven’t open my proposal here. Here is the link:[GitHub - hzhua/grgsm\_proposal: Proposal for GSoC 2014 on gr-gsm](https://github.com/hzhua/grgsm_proposal) If you have any suggestions, please don’t be hesitate to contact me. Thanks toSylvain M. for his help on reviewing my first draft. Thanks toPiot Krysik for his suggestions on gr-gsm. Best wishes, Zhenhua ---
**Author:** ![zhenhua\_han](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/z/d2c977/32.png) [@zhenhua\_han](https://www.ruby-forum.com/u/zhenhua_han)\ **Post date:** [March 11, 2014, 10:01am UTC](https://www.ruby-forum.com/t/proposal-for-gsoc-on-gr-gsm/239700/3 "2014-03-11T10:01:48Z")
On 03/11/2014 04:40 AM, zhenhua han wrote: > Thanks to Sylvain M. for his help on reviewing my first draft. > Thanks to Piot Krysik for his suggestions on gr-gsm. Hey, congrats on publishing the first proposal! It looks quite good. It’s unclear if you have good algorithms to implement your deliverables. A few hints: - The FCH detection can be efficiently implemented using an adaptive filter. Here’s a paper that explains the technique, although it’s very poorly written: [http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=1404796&url=http://ieeexplore.ieee.org/xpls/abs\_all.jsp?arnumber=1404796](http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=1404796&url=http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1404796) There’s also some code for this somewhere… can’t find it right now. - A CEL student wrote a highly optimized MLSE, specifically for GSM, a while back (a _long_ while back, it still uses autotools). Still, the code is very good, and there’s a lot to be taken out of this. He tried out a lot of compiler switches, too, so check out lib/Makefile.am. > **[GitHub - pgoeser/gnuradio-mlse: an out-of-tree MLSE deconvolution system for...](https://github.com/pgoeser/gnuradio-mlse)** > > an out-of-tree MLSE deconvolution system for gnuradio It assumes frame synchronization (i.e. post-SCCH sync), but you just drop in a frame, and it returns the equalized result. MB ---
**Author:** ![zhenhua\_han](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/z/d2c977/32.png) [@zhenhua\_han](https://www.ruby-forum.com/u/zhenhua_han)\ **Post date:** [March 11, 2014, 10:19am UTC](https://www.ruby-forum.com/t/proposal-for-gsoc-on-gr-gsm/239700/4 "2014-03-11T10:19:28Z")
Thank you, Martin. I will check these and extend my proposal with more details. Best wishes, Zhenhua 2014-03-11 17:00 GMT+08:00 Martin B. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid):