FPGA Central

Turbo Codes use interleaver to produce high weight codes

but i want to know

what is signinficance of having high weight codes.how can it improv
performance of either decoder or encoder.

how much interleaver are effective in producing high weieght codes
(although the interleaver can increase probability of increasing number o
ones in the output of encoder but still it is not something that can b
granted.while the chance, that the input that would have caused a lo
weight output of the encoder after being shuffed will be there even afte
shuffling, is same as the chance,that the input that would have caused
low weight would be replaced by an input tht would cause a high weigh
output of the encoder after shuffling.)

"khurram712" <[email protected]> wrote in message
news:[email protected]..

> Turbo Codes use interleaver to produce high weight codes

Incorrect.
Turbo Codes use interleaver to make a thin distance spectrum.

> but i want to know
>
> what is signinficance of having high weight codes.how can it improve
> performance of either decoder or encoder.

Keywords: Hamming distance, turbo code error floor.

> how much interleaver are effective in producing high weieght codes
> (although the interleaver can increase probability of increasing number of
> ones in the output of encoder but still it is not something that can be
> granted.

Producing a consistently high weight code with a fine distance spectrum is
the area of the intense research.

> while the chance, that the input that would have caused a low
> weight output of the encoder after being shuffed will be there even after
> shuffling, is same as the chance,that the input that would have caused a
> low weight would be replaced by an input tht would cause a high weight
> output of the encoder after shuffling.)

Yes, this is what is a problem.

Vladimir Vassilevsky
DSP and Mixed Signal Consultant
www.abvolt.com

Keywords: Hamming distance, turbo code error floor.

i knew what hammind distance is

but couldnt know much about error floor...but it seems to be relevan
....

all i could get was one wiki link...and i dont think that it i
enough....please elaborate it here...or give me some link that could b
helpful in understanding it better....