Signal Processing in digital communications — The fall of science

The last decades has seen a fast growth in published papers concerning the scientific investigation and design of digital communication systems. There is a well developed theory for this purpose, since long. Central here is the theory for Hypothesis Testing and Random Processes. This approach has been abandoned over the years, resulting in applying procedures used in the area of Signal Processing. This results in non-optimal solutions and the underlying models are erroneous and will result in contradictions. This paper will give some simple basic examples of ad hoc approaches using Signal Processing and also point out some obviously erroneous approaches. This will involve the use of sampling, treatment of unknown channels and the general treatment of band limited Rayleigh Fading. The latter will demonstrate the loss of Implicit Diversity, using Signal Processing approaches. Many more examples can be listed but this paper will be mainly limited to these simple examples. Instead references are given for a detailed treatment.