Implementation complexity

 

As the length of a block code increases, two problems begin to emerge:
  • The time taken to collect k bits to form a block increases with increasing block length, introducing delay into the transmission process which may be unacceptable for real-time applications such as voice transmission.
  • The decoder complexity increases almost exponentially with block length as the decoder searches through 2k valid code words to find the best match with the incoming 2n possible coded blocks. In addition to the complexity, the decoding delay can be significant.