Full duplex system phase noise suppression method based on two-stage adaptive filtering

Abstract

The invention discloses a full duplex system phase noise suppression method based on two-stage adaptive filtering. The method comprises the following steps: 1) a first adaptive filter of a full duplexnode transmits a signal x(n) and an expected signal r(n) to complete time domain channel estimation, an estimated value is obtained, then an error signal is calculated, and time domain self-interference elimination is carried out; then CP is removed and the signal is converted into a frequency domain to obtain a frequency domain signal E1(k); 2) the full duplex node obtains a frequency domain signal X(k) of the emission signal x(n) from the E1(k), and a second adaptive filter of the full duplex node obtains a phase noise frequency domain estimation value delta(k) according to the A(k) and theE1(k); and an error signal E2(k) is obtained according to the E1(k) and the delta(k) to complete phase noise suppression. The self-interference elimination capability of the scheme has high performance gain, and the phase noise is suppressed.

Description

technical field [0001] The invention belongs to the technical field of communication, and in particular relates to a phase noise suppression method of a full-duplex system based on two-stage adaptive filtering. Background technique [0002] In order to alleviate the contradiction between the shortage of spectrum resources and the increasing demand for bandwidth, people are devoting themselves to research on a full-duplex (Full Duplex, FD) technology that can improve spectrum efficiency. Compared with the existing Frequency-Division Duplexing (FDD) and Time-Division Duplexing (Time-Division Duplexing, TDD) technologies, the full-duplex technology can theoretically achieve double the spectral efficiency, and has the ability to solve hidden terminal Problems, improve relay communication efficiency and enhance communication security and other advantages. At present, FD technology has become one of the key technologies of the fifth generation communication technology (5th Genera...

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Problems solved by technology

[0004] With the in-depth research on the self-interference cancellation mechanism, scholars have found that in addition to the linear channel in the actual system, nonlinear factors in the circuit, such as phase noise, power amplifier (Power Amplifier, PA) nonlinear effects, and IQ imbalance, etc., Both will reduce the elimination ability of the system, among which, the most serious impact on the system is the phase noise

For Orthogonal Frequency Division Multiplexing (OFDM), phase noise will generate common phase error (Common Phase Error, CPE) and subcarrier interference (Inter-Carrier Interference, ICI), if not suppressed, then It will greatly reduce the self-interference cancellation ability of the system, thus hindering the practical application of full-duplex technology

One of the existing suppression schemes for phase noise is only applicable to the shared oscillator and does not consider the useful signal at the far end. The other scheme uses the minimum mean square error (Minimum Mean Square Error, MMSE) to estimate the phase noise coefficient. Know the channel state information, which is more difficult in the actual system

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