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In this paper, we propose a generalized method of high-level three dimensional (3D) signal constellation mapping based on the most basic 3D structure: regular tetrahedron cells. First, we redefined the waveform design, the normalized frequency and phase modulation for the geometric construction of tetrahedron cells. Then, the new topology of tetrahedron(More)
Frequency spectrum resource is the most important and fundamental resource for various information systems such as communication systems, radar systems and so on. In order to overcome the conflicts between the scarcity and low usage efficiency, cognitive capability becomes more and more important for future information system designs. In this paper, we give(More)
Transform domain communication system (TDCS) is a potential candidate for cognitive radio (CR). It is immune to the interception and has the characteristics of high spectral utilization. Nevertheless, large peak-to-average power ratio (PAPR) of the time domain signal inherently makes TDCS particularly sensitive to nonlinear distortion caused by the high(More)
First, this paper analyzes the performance of the linear frequency modulation (LFM) interference in PN spread-spectrum communication systems. Second, in the light of suppressing the side-lobe of periodic LFM in fractional Fourier transform (FRFT) domain, a method combined transform-domain and time-domain is proposed, this method improves the processing gain(More)
To reach a compromise between efficient dynamic performance and high tracking accuracy of carrier tracking loop in high-dynamic circumstance which results in large Doppler frequency and Doppler rate, a tracking loop structure aided by the estimation of Doppler rate is proposed in this paper. First, the instant self-correlation function is used for a process(More)
First-principles density functional theory (DFT) simulations were carried out to study the strain dependence on the electronic and optical properties of cadmium selenide (CdSe) nanowires (NWs). The band structures, effective masses of electron and holes, dielectric properties, and other optical properties (such as extinction coefficient, optical(More)
Compared with pseudo-noise (PN) sequences, chirp signals have obvious advantages in acquisition time and tracking performance in the field of telemetry, track, and command (TT&C) with the large Doppler tolerance. In this paper, an effective tracking loop for chirp spread spectrum communication is proposed, which can realize chirp signals modulated by(More)