Comments on: Convolutional code http://www.dsplog.com/2009/01/04/convolutional-code/ Signal Processing for Communication Fri, 30 Jul 2010 01:36:27 +0000 http://wordpress.org/?v=2.9.2 hourly 1 By: Krishna Sankar http://www.dsplog.com/2009/01/04/convolutional-code/#comment-24718 Krishna Sankar Sat, 03 Apr 2010 23:48:08 +0000 http://www.dsplog.com/?p=376#comment-24718 @hina: Plz refer Digital Communications by Proakis @hina: Plz refer Digital Communications by Proakis

]]> By: Krishna Sankar http://www.dsplog.com/2009/01/04/convolutional-code/#comment-24349 Krishna Sankar Mon, 29 Mar 2010 23:26:56 +0000 http://www.dsplog.com/?p=376#comment-24349 @manisha: Some relevant links which I picked up from a quick Googling. (a) Tone reservation : where some of the unused subcarriers in an OFDM system is modulated to reduce the PAPR. (b) MERL has a paper on PAPR reduction by oversampling, soft clipping and filtering. PAPR Reduction for WiMAX OFDM Systems http://www.merl.com/projects/papr/ (c) Nice comp.dsp thread on this topic Has The peak-to-average ratio problem of OFDM been solved? http://tinyurl.com/6jn9ql @manisha: Some relevant links which I picked up from a quick Googling.
(a) Tone reservation : where some of the unused subcarriers in an OFDM system is modulated to reduce the PAPR.
(b) MERL has a paper on PAPR reduction by oversampling, soft clipping and filtering.
PAPR Reduction for WiMAX OFDM Systems
http://www.merl.com/projects/papr/
(c) Nice comp.dsp thread on this topic
Has The peak-to-average ratio problem of OFDM been solved?
http://tinyurl.com/6jn9ql

]]> By: Krishna Sankar http://www.dsplog.com/2009/01/04/convolutional-code/#comment-24348 Krishna Sankar Mon, 29 Mar 2010 23:26:11 +0000 http://www.dsplog.com/?p=376#comment-24348 @manisha: Convolutional coding is an error correction technique... Am not sure how it can be applied for PAPR reduction in OFDM @manisha: Convolutional coding is an error correction technique… Am not sure how it can be applied for PAPR reduction in OFDM

]]> By: Krishna Sankar http://www.dsplog.com/2009/01/04/convolutional-code/#comment-24347 Krishna Sankar Mon, 29 Mar 2010 23:25:28 +0000 http://www.dsplog.com/?p=376#comment-24347 @manisha: Sorry, did not understand your query @manisha: Sorry, did not understand your query

]]> By: Krishna Sankar http://www.dsplog.com/2009/01/04/convolutional-code/#comment-24236 Krishna Sankar Sun, 28 Mar 2010 09:12:44 +0000 http://www.dsplog.com/?p=376#comment-24236 @Arun Showry; Sorry, I have not tried to simulate decoder of recursive convolutional codes @Arun Showry; Sorry, I have not tried to simulate decoder of recursive convolutional codes

]]> By: Krishna Sankar http://www.dsplog.com/2009/01/04/convolutional-code/#comment-24235 Krishna Sankar Sun, 28 Mar 2010 09:11:47 +0000 http://www.dsplog.com/?p=376#comment-24235 @arun showry: Firstly, am not a Dr. :) Secondly, the paper which you mention is written by Krishna R Narayan and not me Thirdly, I have not studied Turbo code in much detail. Hence unable to answer @arun showry: Firstly, am not a Dr. :)
Secondly, the paper which you mention is written by Krishna R Narayan and not me
Thirdly, I have not studied Turbo code in much detail. Hence unable to answer

]]> By: arun showry http://www.dsplog.com/2009/01/04/convolutional-code/#comment-23673 arun showry Fri, 19 Mar 2010 23:09:44 +0000 http://www.dsplog.com/?p=376#comment-23673 Hi Dr.Krishna I am trying to implement you paper "A novel Arq technique using the turbo coding principle" I got the turbo decoder working , but in your paper you mention: when a retransmission takes place the LLR's are used as a priori information. before the LLR's of the previous iteration are used in the current iteration what changes are to be done to the previous LLR;s. I am doing this: deinterleave to get original sequence and then interleave according to the interleaver pattern of second turbo enocder . Is there anything wrong in what i am doing to the LLR's. thank you, Arun Hi Dr.Krishna
I am trying to implement you paper “A novel Arq technique using the turbo coding principle”

I got the turbo decoder working , but in your paper you mention: when a retransmission takes place the LLR’s are used as a priori information.
before the LLR’s of the previous iteration are used in the current iteration what changes are to be done to the previous LLR;s.

I am doing this:
deinterleave to get original sequence and then interleave according to the interleaver pattern of second turbo enocder .

Is there anything wrong in what i am doing to the LLR’s.

thank you,
Arun

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