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Abstract
Today's world thrives on information exchange. Hence the need of the day is the information be protected well enough to the transmitted over a noisy environment. This is achieved by adding redundant bits to the information bit streams. If the purpose of adding redundancy bits is just to detect error and inform the sender to retransmit the information. Forward error correction (FEC) is another way of adding redundancy to the information bit stream. So, error can be detected and corrected by preventing needed retransmission.
Turbo codes is a very powerful error correction technique that has made tremendous impact on channel coding in last few years. Turbo code bit error rate drops very rapidly with increasing Eb/N0 values. It achieves 10^-5 BER with Recursive Systematic Convolution encoder .The iterative decoding mechanism, RSC and use of interleave are the characteristics features of turbo codes. That it enhance data transmission efficiency in digital communication system. Turbo codes play a major role in multimedia services in mobile phones. The performance of turbo codes is superior with a little Eb/No.
The original JPEG (Joint Photography Expert Group) image is encoded using turbo codes and subjected to additive white Gaussian noise. In this random interleaver is used and MAP decoding algorithm is used. We can almost retrieve original image by number of iterations by iterative decoder. As the number of iterations increases the noise in image removed.