-
June 27th, 2017, 12:45 AM
#1
How to proceed and execute Decoding Using Tanner Graph in C
Hi,
I know LDPC decoding logic but i don`t have knowledge in Data Structure. Please help me How to proceed LDPC Decoding Using Tanner Graph in C Coding? Please teach me in writing coding step by step.
In that process i have been provided with a H matrix,code word like [c1, c2, c3, c4, c5, c6] =[1 0 1 0 1 1].
The received word is r=[X 0 1 X 1 1], where X = missing bits. c1 and c4 are missing bits, i need to find missing bits using tanner graph.
In tanner graph, there are two nodes : Check Nodes and Variable Nodes
—Variable-nodes: Correspond to bits of the codeword or equivalently, to columns of the parity check matrix.
There are n v-nodes
Check-nodes: Correspond to parity check equations or equivalently, to rows of the parity check matrix. Also known as constraint nodes.
—There are m = (n-k) c-nodes.
STEPS :
c4 bit is recovered first and then c1 bit is recovered. Total 2 iterations are used.
1. Messages are passed from variable nodes to check nodes. At check nodes they are processed and the results are stored
using the constraint c3^c4^ c6=0, we calculate the value of c4.
2. Update the values at variable nodes, Messages (value of c4 ) are passed from check nodes to variable nodes
3.Updated messages are again transferred from variable nodes to check nodes.
Using constraint: c1^c2^c3^c4=0
Value of c1 is calculated
4. Values are updated at variable nodes, Message (value of c1) is passed from check nodes to variable nodes
Finally, missing bits are identified
Tags for this Thread
Posting Permissions
- You may not post new threads
- You may not post replies
- You may not post attachments
- You may not edit your posts
-
Forum Rules
|
Click Here to Expand Forum to Full Width
|