Power-Bandwidth Efficiency and Capacity of Wireless Feedback Communication Systems

The paper is devoted to the analysis of problems appearing in optimisation and improvement of the powerbandwidth efficiency of digital communication feedback systems (FCS). There is shown that unlike digital systems, adaptive FCS with the analogue forward transmission allow full optimisation and derivation of optimal transmission-reception algorithm approaching their efficiency to the Shannon boundary. Differences between the forward channel capacity and capacity of adaptive FCS as communication unit, as well as their influence of the power-bandwidth efficiency are considered. Keywords–Feedback systems, analogue transmission, efficiency, optimisation, threshold effect, Shannon’s boundary.