The book provides an in-depth analysis of the properties of individual cascades of RF front-end receivers, their design implementation, optimization of characteristics to achieve the highest transfer coefficient and minimum introduced distortion. Particular attention is paid to the characteristics of the preselector, which determines the sensitivity of the receiver, selects the operating frequency band and suppresses collateral channels. Depending on the range of operating frequencies, the bandwidth of received frequencies and the selected structural scheme of the receiver, the front-end can be tunable or with a fixed setting. A low-noise amplifier can be an integral part of the front-end, the AE mode of which is selected based on the condition of minimum noise figure and achieving the highest gain. The structure of the RF front-end in modern receivers of analog and digital signals always includes a frequency converter from the operating frequency range to the intermediate frequency range or BB (base band). It is described how the application of orthogonal modulation methods in digital systems allowed to realize the optimal reception of signals, when the processing of received signals is performed by correlation methods, and the decision on the received information bit is made on the basis of the analysis of a group of symbols (correlation functions). It is shown how this allowed to organize the transmission of information flows to a specific subscriber of the cell, and the use of MIMO technology to increase the SNR at the receiver input.