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As one of multi-carrier modulation schemes suitable for 5G/B5G scenarios, the generalized frequency division multiplexing (GFDM) waveform has flexible time-frequency resource distribution. To further reduce out-of-band power leakage of GFDM system, a multiparameter variable GFDM prototype filter is proposed. The flexible configuration of multiparameter method achieves better out-of-band power suppression performances and a precise control of out-of-band power efficiency suppression. Simultaneously, theoretical bit error rate (BER) expression of GFDM system with multiparameter variable filter under frequency selective fading channel is derived. In addition, in order to further improve the BER performance of GFDM system in complex channel scenarios, a message passing (MP) receiver suitable for multiparameter GFDM waveforms is proposed, and the mathematical model of the MP receiving algorithm is given according to the equivalent channel matrix. Simulation results show that the MP receiver can effectively improve the BER performance of GFDM waveform in complex channels. Moreover, the variable filter based on multiparameter can effectively suppress out-of-band power with slight BER loss in comparison with traditional raised cosine (RC) filter. [ABSTRACT FROM AUTHOR]

OFDM system is widely used in mobile communication because of its high spectral efficiency and strong anti-multipath capability. However, in high dynamic scenarios, the Doppler shift between the transmitter and the receiver destroys the orthogonality between the sub-carriers, resulting the interference between the sub-carriers and distortion of the signal, which greatly degrades the system performance. In this paper, a mathematical model of Offset-OFDM system was established and the Doppler response formula of OFDM system in high white channel was derived. Furthermore, we investigated the factors that influence the performance of OFDM. This study laid the foundation for determining OFDM system parameters in high dynamic scenarios.

A long‐standing enigma in oceanography is why terrestrial organic matter is "missing" in the global ocean, despite the considerable discharge into it every year. Although some explanations, such as mineralogical composition, hydrodynamic processes, and priming effect, have been proposed, we hypothesize that the essential mechanism behind the missing organic matter is microbial processing, for which the underlying coupled geochemical, molecular, and genetic evidence is unknown. An ultra‐large‐volume, long‐term river–seawater stratified simulation system was constructed to unravel the microbially driven fate of terrigenous particulate organic matter (POM) in oceans. Analysis of combining the molecular with POM chemical composition data suggests that Bacteroidetes could act as pioneers in the processing of terrigenous POM in oceans, degrading high‐molecular‐weight, high‐carbon compounds such as polysaccharides. Remaining low‐molecular‐weight nitrogenous organic matter is subsequently degraded by Planctomycetes and Proteobacteria. Isotopic signals show that this preferential degradation causes a distinct "aging" effect of POM, and along with nitrification enhanced by remineralization, causes a decrease in the POM C : N ratio. Degradation of terrigenous POM and bacterial biomass biosynthesis leads to positive deviations in δ15N and δ13C. Relatively refractory hydrocarbons, aromatic compounds, and phenols are accumulated by microbial processes in this system. This study provides mechanistic insights into the missing chemical and isotopic signals and microbially driven fate of terrigenous POM in the ocean, with important implications for how riverine material input affects marine carbon and nitrogen cycling. [ABSTRACT FROM AUTHOR]

Link16 data chain is applied to major combat platforms with its strong anis interference ability, but the transmission rate and utilization of Link16 are low. For this problem, a truncated code slit keying (TCSK) method based on one-way coupled map lattice (OCML) spatiotemporal chaotic sequence is proposed in this paper. The system uses spatiotemporal chaotic sequence under the OCML model as base code, then shortens the length of each chip which carries information to the original 1 /P, and mirrors each chip symmetrically to obtain a spread spectrum chip with a total length of 2/P to transmit. Compared with the original sequence, the length of this chip reduces by half to improve the transmission rate of the system. OCML sequences have great pseudo randomness and autocorrelation, and many spread spectrum sequences can be generated under the model, each sequence is unique, so one channel can accommodate lots of spread spectrum signal, which improves the efficiency of bandwidth tremendously. The bit error rate (BER) performance in multipath channel model is simulated, and the simulation results show that the scheme can effectively improve performance of system under multipath fading. [ABSTRACT FROM AUTHOR]

In order to solve the problem of inter-carrier interference (ICI) in fractional Fourier transform orthogonal frequency division multiplexing (FrFT-OFDM) system caused by time-frequency double selective channel, a joint self-cancellation scheme based on ICI self-cancellation coding and frequency offset compensation is proposed. In this scheme, the self-cancellation matrix with phase compensation is used to encode the signal. By taking advantage of the structural advantage of the adjustable rotation angle of the subcarriers in the FrFT-OFDM system, the fractional Fourier transform is carried out under the appropriate rotation angle to compensate the frequency offset, so as to achieve better ICI suppression effect than the traditional ICI self-cancellation technology under the same coding efficiency. The simulation results verify the performance of the scheme. [ABSTRACT FROM AUTHOR]