Millimeter wave (mmWave) communications and cognitive radio technologies constitute key of improving the spectral efficiency communications. Hence, we conceive a hybrid secure precoder for enhancing physical layer security mmWave wiretap channel, where secondary transmitter broadcasts confidential information signals to multiple users under interference temperature constraint primary user (PU)....

An approach for the construction of optimal analog wavelet bases is presented. First, the definition of an analog wavelet is given. Based on the definition and the least-squares error criterion, a general framework for designing optimal analog wavelet bases is established, which is one of difficult nonlinear constrained optimization problems. Then, to solve this problem, a hybrid algorithm by c...

Massive multiple-input multiple-output (MIMO) is promising for low earth orbit (LEO) satellite communications due to the potential in enhancing spectral efficiency. However, conventional fully digital precoding architectures might lead high implementation complexity and energy consumption. In this paper, hybrid analog/digital solutions are developed downlink operation LEO massive MIMO communica...