Phase Noise Suppression Method for Full-duplex System 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 is as follows: 1) The first adaptive filter of the full-duplex node transmits the signal x(n) and the desired signal r(n) to complete the time-domain channel estimation, obtains the estimated value, then calculates the error signal and performs time-domain self-interference cancellation ; then remove the CP and convert the signal to the frequency domain to obtain the frequency domain signal E 1 (k); 2) Full-duplex node slave E 1 In (k), the frequency domain signal X(k) of the transmitted signal x(n) is obtained, and then the second adaptive filter of the full-duplex node is calculated according to A(k), E 1 (k) Obtain the phase noise frequency domain estimate δ(k); then according to E 1 (k), δ(k) to get the error signal E 2 (k), complete phase noise suppression. The self-interference cancellation capability of this scheme has high performance gain and suppresses phase noise.

Description

Technical field [0001] The present invention belongs to the field of communication, and is specifically related to a full duplex system phase noise suppression method based on two-stage adaptive filtering. Background technique [0002] In order to alleviate the contradiction between shortage of spectrum resources and increasing bandwidth demand, people are committed to studying full-duplex technologies (Full Duplex, FD) that can improve spectral efficiency. Compared with the existing frequency division diverduplexing, FDD, the TIME-DIVISION DUPLEXING (TDD) technology, the full-duplex technology can achieve double spectrum efficiency, and has a resolution terminal Problems, improve relay communication efficiency and enhance communication security. At present, FD technology has become one of the key technologies of the fifth generation communication technology (5G). However, since the emission and reception work are in the same time and the same frequency, the local receiver receiv...

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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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