I tried convolutional coding and Reed-Solomon (RS) (block coding technique) for wireless channel where the input data is bitstream.

Convolutional coding achieved lower BER comparing with RS. If the SNR of channel decrease around 15dB, convolution code's BER becomes more than that of the system without channel coding, where RS achieved a small improvement in the BER.

I wonder if any one has an explaination for what happened ?

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    $\begingroup$ It could be easier if you post the BER curves and describe your channel model (AWGN, Rayleigh block/fast fading, ...). $\endgroup$ – AlexTP Dec 23 '17 at 16:42
  • $\begingroup$ channel model is AWGN $\endgroup$ – user24907 Dec 23 '17 at 17:58
  • $\begingroup$ One code is better than the other at achieving a better Ber. What's your question? $\endgroup$ – Marcus Müller Dec 23 '17 at 21:28
  • $\begingroup$ Complexity is part of the performance trade space $\endgroup$ – user28715 Dec 24 '17 at 0:57

Reed-Solomon codes are good for correcting bursts of errors (such as those that often occur in computer memory systems such as RAM, or on less volatile media such as CDs and DVDs) or at the output of block decoders -- either a received word is completely correct, or it has multiple errors all within the codeword length -- or at the output of convolutional decoders -- if a decoder goes off the correct path, there is a burst of errors until the decoder gets back on the correct path. Reed-Solomon codes are not all that good for correcting random errors such as those that occur in AWGN channels. It has been common practice for many students (as well as their faculty member advisors, who really ought to know better), not to mention engineers in the communications industry, to put up graphs comparing how well convolutional codes do compared to Reed-Solomon codes in preparation for touting the advantage of their thesis work or product over the competition. As a matter of fact, systems needing to meet the most stringent performance criteria often use a concatenated coding system in which the outer code is a Reed-Solomon code and the inner code (the one whose codewords are transmitted over the channel) is a convolutional or turbo or LDPC code, all of which are well-matched to the characteristics of the channel.

  • $\begingroup$ @ Dilip Sarware, Is that the same if the transmitted is SPIHT compressed image? Will be convolutional coding be more suitable for fading channel? $\endgroup$ – user24907 Feb 18 '18 at 11:36

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