# SOCIS project update 5 **URL:** \ **Category:** GNU Radio\ **Created:** [July 3, 2015, 8:34pm UTC](https://www.ruby-forum.com/t/socis-project-update-5/242575 "2015-07-03T20:34:47Z")\ **Posts on this page:** 1\ **Page:** 1
**Author:** ![Detlef\_R](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/58f4c7/32.png) [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\ **Post date:** [July 3, 2015, 8:34pm UTC](https://www.ruby-forum.com/t/socis-project-update-5/242575/1 "2015-07-03T20:34:47Z")
Hey community! It’s Friday! So it’s time for another project update. This week was all about decoders. After I had finished a successive cancellation decoder, I started working on a successive cancellation list decoder. By the end of last week, I was confident, I could finish it earlier this week. Those hopes were smashed when I realized that my first approach had flaws. So now my design is spread over multiple classes. One that offers all the necessary functions to perform successive cancellation decoding. A second class which uses those functions to decode frames. And another class for successive cancellation list decoding. Also, I added a class which deals with everything related to the list used by the list decoder. According to papers like [3] natural bit indexing order is beneficial in terms of performance. Thus I changed the decoder to use natural bit order. I spent some time on a decoder version which would store bit estimates in a packed array in contrast to on bit per byte. This should make the so-called combine operation faster. It is the most demanding operation at the moment. I realized that realistic tests require realistic channel info. Currently, I use BEC Z-values for encoder/decoder parameterization but encoder/decoder are designed to work with BSC. Therefore, I decided to focus on channel construction next week. Afterwards the encoder/decoder should be usable in a real flowgraph. More info and current project progress can be found in [1] and [2]. Cheers Johannes [1] [GitHub - jdemel/gnuradio: GNU Radio](https://github.com/jdemel/gnuradio) [2] [GitHub - jdemel/socis-2015-gr-results: ESA SOCIS 2015 files and information](https://github.com/jdemel/socis-proposal) [3] [http://arxiv.org/pdf/1504.00353v1.pdf](http://arxiv.org/pdf/1504.00353v1.pdf)