"Navigare necesse est!" - If one compares wired and wireless/mobile communications several differences can berecognized in such fields as security, power consumption, mediumaccess, channel behavioretc. However, themost differently handled resource is bandwidth. In case ofwired networkslink capacity can overcome almost any limitations by deploying optical fibres. Spectral efficiency is one of the mostsignificant key parameters of every mobile system. Spectrally efficient wireless solutionsare fairly complex, they consist of techniques applied in physical and data link layers.Call Admission Control (CAC) methods are very important since they ensure Quality ofService (QoS) while increasing spectral efficiency so they provide tradeoff between twocompeting aspects. Quantum computing and communications just appeared in infocomsystems. They offer completely new principles and techniques which are not available inclassical computing and communications. Therefore, it is worth attacking wide range ofcomputationally complex problems of infocom systems from data base searching to usefulsignal detection in multiuser environment.