Quadrature windowed orthogonal frequency division multiplexing system, active interference cancellation method and application

Abstract

The invention belongs to the technical field of wireless communication, and discloses a quadrature windowed orthogonal frequency division multiplexing system, an active interference cancellation method and application, the quadrature windowed orthogonal frequency division multiplexing system comprises a transmitter and a receiver; and the transmitter comprises a serial-to-parallel conversion module, a symbol mapping module, a subcarrier mapping module, a multi-carrier modulation module, a parallel-to-serial conversion module, a quadrature windowing module, a quadrature active spectrum leakageoffset module and an up-conversion module. According to the quadrature windowed orthogonal frequency division multiplexing system provided by the invention, an active interference cancellation technology with a variable waveform roll-off speed is applied, so that the spectrum leakage of a signal can be suppressed more effectively under the condition of not generating any inter-subcarrier interference, and the spectrum leakage of the orthogonal frequency division multiplexing system is reduced to below -75dB, and therefore, the spectral efficiency of the wireless communication system is improved; and meanwhile, the energy efficiency of the active interference cancellation method is remarkably improved, and the calculated amount is reduced.

Description

technical field [0001] The invention belongs to the technical field of wireless communication, and in particular relates to an orthogonal windowed orthogonal frequency division multiplexing system, an active interference canceling method and an application thereof. Background technique [0002] At present, broadband wireless communication is facing a serious problem of insufficient spectrum resources, and the Orthogonal Frequency Division Multiplexing (OFDM) system widely used in broadband wireless communication has serious spectrum leakage, which reduces spectrum efficiency. Suppressing the spectral sidelobe leakage of OFDM signals is of great significance for improving wireless spectrum efficiency and alleviating the shortage of wireless spectrum resources. [0003] The methods for suppressing the spectrum leakage of OFDM signals mainly include windowing method and active interference cancellation method (AIC), and they can also be used in combination. Among them, the exi...

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Problems solved by technology

[0006] (1) Although the existing orthogonal active interference cancellation does not cause interference to the data subcarriers in the system, its sidelobe suppression effect is insufficient

[0007] (2) The existing technology combines the windowing method with the active interference cancellation method, and the improvement of the sidelobe suppression effect is limited

[0008] (3) The conventional windowing method is to first add a cyclic prefix (CP) to the OFDM signal and then add the window. The windowing process does not affect the existing OFDM data part and CP part, but the data subcarriers after windowing will be separated from each other. is no longer orthogonal, further application of active interference cancellation does not work very well

[0011] (2) Windowing generally affects the orthogonality between subcarriers, further affecting the efficiency of interference cancellation

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