|
From: | Kyeong Su Shin |
Subject: | Re: How to add fec in GMSK |
Date: | Wed, 29 Apr 2020 08:44:11 +0000 |
Hello Quenten:
"Hamming Code" is a type of an forward-error correction code (FEC). See: https://en.wikipedia.org/wiki/Hamming_code . It is not related to low-pass filtering (you really should not have that there). I mentioned Hamming Code because it is usually the first
code that you learn in the school.
For an example, Hamming(7,4) takes a 4-bit data, and generates a 7-bit code. That means, if you use Hamming(7,4), the payload size of the "Oacket Encoder" (which you really shoudn't be using, but I guess you already know that) must be an integer multiple
of 7 (bits). If you don't do that, you will need to implement additional handling processes to fix that.
In your flow graph, you are using Convolutional Code (which is not a linear code), instead of Hamming Code (which makes sense, as Hamming Code usually makes little sense on wireless communication system). Still, you have to take similar issues into your
consideration. I don't remember the exact details (I didn't use Convolutional code much), but you may have to add paddings and tails on your packets and fix the paylod size to a certain number to get things working (go through WiFi OFDM PLCP and WiFi convolutional
code tutorials, if you are sticking with Convolutional code).
Also, I do not see the "Packet Decoder" in your flowgraph.
WX GUI is no longer supported, and some error messages that you posted are about WX GUI, so consider using QT GUI instead.
Finally, please note that it will still miss some packets (mostly during the beginning of the transmission).
(I added address@hidden back to the recipant list.)
Regards,
Kyeong Su Shin보낸 사람: Quenten . <address@hidden>
보낸 날짜: 2020년 4월 29일 수요일 오후 4:57 받는 사람: Kyeong Su Shin <address@hidden> 제목: Re: How to add fec in GMSK hello, Kyeong Su Shin,
I added hamming with a low pass filter(only way I know how to add Hamming in flowgraph) but when I run this is get the following results from GNU:
bits per symbol = 1
For the result ofthe graphs see file attached.
I added the Low Pass in the original Grc before the Gmsk Demod, as can be seen below:
Best regards,
Q Op ma 27 apr. 2020 om 17:50 schreef Kyeong Su Shin <address@hidden>:
|
[Prev in Thread] | Current Thread | [Next in Thread] |