Self-interference elimination method of co-frequency co-time full duplex system

Abstract

The invention provides a self-interference elimination method of a co-frequency co-time full duplex system. The method comprises the following steps of introducing an analog reference signal from a transmitting end, performing dividing operation on a received signal and the reference signal for converting a self-interference signal to a DC signal and a frequency doubling component, and changing an objective signal to a low-frequency signal and a frequency doubling component; transmitting the DC signal and the low-frequency signal to a low-pass filter and a DC blocking filter, filtering the self-interference signal, and keeping the low-frequency signal (objective signal); and before demodulation, multiplying the low-frequency signal with a transmitting end baseband reference signal for recovering the waveform of the objective signal. The self-interference elimination method of the co-frequency co-time full duplex system has advantages of finishing self-interference elimination before digital-to-analog conversion, eliminating effect of a channel characteristic to interference elimination, reducing quantization noise and reducing technical complexity in self-interference elimination.

Description

technical field [0001] The invention relates to the same-frequency and simultaneous full-duplex interference elimination technology, which belongs to the field of wireless communication. Background technique [0002] In the traditional half-duplex technology, uplink and downlink signals are distinguished by orthogonal frequency domain or time domain resources, and the spectrum efficiency is low. Simultaneous full-duplex technology on the same frequency, as a key technology to improve spectrum efficiency, realizes signal transmission in two directions on the same physical channel, so that each communication node can simultaneously send and receive uplink and downlink signals on the same frequency band, which has won industry recognition. extensive attention. Compared with the traditional half-duplex technology, the same-frequency simultaneous full-duplex technology can make full use of spectrum resources and achieve greater throughput capacity, and has become one of the key ...

AI Technical Summary

Problems solved by technology

[0005] First of all, the radio frequency interference elimination module needs to adjust the amplitude and phase of the reference signal according to the channel response and residual interference. The time-varying characteristics of the wireless channel cause the radio frequency interference elimination circuit to adaptively adjust parameters to track channel changes. The implementation complexity of the adaptive algorithm higher;

[0006] Secondly, due to the multipath effect of the wireless channel, the interference signal is the result of the superposition of multipath interference signals. The existing radio frequency interference elimination methods can only eliminate the interference of the main path, but cannot eliminate the interference of other paths, and the interference elimination effect is limited;

[0007] Third, the signal after radio frequency interference elimination is converted into a digital signal. Due to the low resolution or insufficient dynamic range of the ADC, the ADC cannot accurately obtain the useful components in the received signal, resulting in the loss of the useful signal during the quantization process, which in turn affects the baseband data. accuracy of demodulation;

[0008] Finally, baseband interference elimination requires corresponding signal processing algorithms to estimate the interference channel, which is complex in technology and difficult to implement

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