AN EFFICIENT CONVOLUTIONAL CODING DECODING STRATEGY FOR CHANNELS WITHMEMORY

Many digital communication channels are affected by errors that tend t o occur in bursts. A great deal of work has been devoted to finding go od burst-error-correcting codes and developing burst-error-correcting schemes. However, burst-error-correcting codes are generally not effec tive for long bursts. Some burst-error-correcting schemes suffer long delay in decoding. Others are very sensitive to random errors in the g uard space. Most of these schemes are not adaptive to channel conditio ns. In this paper, a new adaptive scheme is proposed to overcome these drawbacks. The scheme employs a combination of two complementary punc tured convolutional (CPC) codes. One of the codes is used for burst de tection and for channel state estimation, and both codes are used for error correction. The proposed scheme is analyzed over a two state Mar kov chain channel model. Unlike existing burst-error-correcting scheme s, it is shown that the proposed scheme is adaptive to channel conditi ons and less sensitive to errors in the guard space. For the same dela y, the proposed scheme offers better performance than the interleaving schemes. When the channel is heavily corrupted by bursts, the improve ment is even more pronounced.