## First piece of content

I’ve uploaded a report we wrote to intuitively explain why a free distance of two is a necessary condition for supporting iterative decoding convergence to an infinitesimally low probability of error. This is relevant to Variable Length Error Correction (VLEC) codes, Variable Length Codes (VLCs), Reversible Variable Length Codes (RVLCs) and Fixed Length Codes (FLCs). This relates to the EXtrinsic Information Transfer (EXIT) chart analysis of iterative decoding convergence in concatenated codes.

Tags: convergence, EXIT chart, FLC, free distance, iterative decoding, RVLC, VLC, VLEC

February 1st, 2015 at 6:28 pm

sir Plz I need VLEC encoding and decoding for 22 symbols

February 4th, 2015 at 7:24 pm

Hello Manju,

I’m afraid that I don’t have any source code for VLEC encoding and decoding that I can share with you.

Take care, Rob.

February 5th, 2015 at 2:02 pm

Sir plz plz give me any hint in finding how to decode the VLEC code in matlab

February 6th, 2015 at 9:34 am

Hi Manju,

You may like to look at the relevant chapters in…

http://eprints.soton.ac.uk/264980/

http://eprints.soton.ac.uk/270911/

Take care, Rob.

February 6th, 2015 at 10:06 am

Thanks for this help sir. Sir plz give me matlab code for maximum likelihood decoding of VLEC

February 6th, 2015 at 5:29 pm

Hi Manju,

I’m afraid that I don’t have any Matlab code for the maximum likelihood decoding of VLEC.

Take care, Rob.

March 1st, 2015 at 2:20 pm

hello sir,

Sir its a request from u plz provide me matlab code for VLEC construction and decoding.plz sir

March 1st, 2015 at 5:26 pm

Hi Manju,

I’m really sorry, but I don’t have any Matlab code for VLEC that I can share with you.

Take care, Rob.

May 12th, 2015 at 9:13 am

Hello sir,

I’m very interested in VLC. For VLC encoding, every thing is OK. But at the receiver side, I have some problems. For VLC decodingm I used MAP algorithm and devide the bit stream to many packet. And I know the number of symbol in 1 Packet. But I dont know can I know the number of bits in 1 Packet?

May 16th, 2015 at 10:06 am

Hi Minh,

In my work, I typically assume that the receiver has knowledge of how many bits and how many symbols are in each packet. In practice, this can be achieved by transmitting this information before transmitting the packet - strong error correction can be applied to ensure that this small amount of information gets through successfully.

Take care, Rob.

May 19th, 2015 at 9:50 am

Hello sir,

I agree with you. it’s so difficult if we don’t know about the length of bits and symbols in one packet. Thanks for your help.

July 28th, 2015 at 9:29 am

Hello Sir,

About VLC decoding, I have one question. We assume that the receiver has knowlegde of how many bits and symbols in each packet. And we transmit this information before transmitting the packet. So when we calculate Eb/N0, we need to calculate for the extra information, and the value of spectral efficiency is changed too. I don\’t know it\’s right or not?

July 31st, 2015 at 11:52 am

Hi Minh,

Ideally, the Eb/N0 calculation should consider the bits used for the side information. However, the effect will typically be negligible, when the frame length is 1000s of symbols. So, most papers do not consider the side information in the Eb/N0 calculation. In fact, most papers assume that the side information is perfectly received, so that it does not need to be simulated.

Take care, Rob.