On the Bit Error Behaviour of Coded DS-CDMA with Various Modulation Techniques

In order to combat transmission errors in digital communication systems, forward error protection based on convolutional codes and interleaving in conjunction with soft decision maximum-likelihood decoding through the Viterbi algorithm is often applied. The expected bit error rate for a given signal-to-noise ratio is generally difficult to foresee for a certain system. In this paper, we introduce a method which vividly treats the error behaviour on particular stages of the receiver, hereby allowing a coarse estimate of the overall bit error rate. Although no close mathematical results are given, several astonishing effects can easily be explained thus providing a better understanding of concatenated systems.