Turbo product code

[trunutsa]

hello, i am working on encoding and decoding of turbo product code(TPC). In TPC along with the received message, we also get channel information. how to get channel information in real time. or how to calculate it? if i had transmitted some message, say 1 0 1 1 0. and received message is 1 0 1 1 1. along with this i am also expecting the channel information. how i will calculate or get it?
Thanks
Regards

Trunutsa

[charan langton]

Typically in Turbo Product Codes, channel information means the knowledge of the SNR which is needed for decoding. The SNR measurement is done by a preamble.

Charan

[trunutsa]

thanks for your reply.

how to measure SNR using preamble? basically how i will get extrinsic information at the decoder side of the TPC.

Trunutsa