Channel coding and source coding

[hot_ice]

Hi!

I'm about to write brifely what I understand about channel coding and source coding. Please correct me, if I'm worng.

Channel Coding: Refers to "Signal Transformation". By signal transformation, we mean that we transform the signals into "better-signals" which can better withstand the channel impairments. So we talk about two things

i) Waveform coding (We either make signals Antipodal or Orthogonal)
ii) Structured sequences (We add redundancy which helps us detecting and correcting errors -- the examples are Linear Block Codes, Convolutional Codes and Turbo Codes.)

Source Coding: Refers to compression. I've not studied it yet. So, I need some brief information about it.

One thing more, in UMTS, we use Convolutional codes. I know, convolutional codes are better than Linear Block codes. But Turbo codes are even better than convolutional codes. So, why do not we use Turbo codes? Btw, how are convolutional codes better than linear block codes?

Anticipating an assertive response... Thx!

 

[Sal]

Help needed...

Hi

You are trying to give new definitions for things that already defined. I suggest you refer to the existent literature and check the definitions for "channel coding" and the other.

About turbo codes, they are better but they demand more complex hardware, greater computational cost which may not be justified for the application you mention.

cheers

Sal