System Applications

Abstract

We believe that examination of a few typical application areas will provide the reader with much of the insight required to effectively utilize coding in communication systems. One such application occurs in systems that require a very powerful code. A practical technique for implementing such a code is that of concatenating two or more codes. With this technique one achieves a high level of performance by trading an increase in overall block length for a reduction in hardware complexity. A second important system application of coding occurs any time the predominant errorcausing mechanism can be attributed to additive white Gaussian noise. Virtually all of the techniques discussed in this book are for correcting random errors and, consequently, are applicable to this problem. Another topic of considerable interest is that of coding for burst noise channels. In this case, the interesting questions are whether interleaving should be used and if so, what structure should be used. A related problem is that of coding for spread spectrum systems (because of the pulsed jammer problem). For these systems some definite conclusions can be made regarding the manner in which coding should be applied. Finally, a problem of a much different nature is that of communicating over limited bandwidth channels. In this case coding can provide substantial gains. This is an extremely interesting problem because the coding scheme should be selected in conjunction with the signal design to obtain the most efficient coding/modulation scheme.