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Novel multi-tap analog self-interference cancellation architecture with shared phase-shifter for full-duplex communications

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Science China(Information Sciences) 2017年第10期60卷 139-154页

作者： Hongtao LU Chuan HUANG Shihai SHAO youxi tang National Key Laboratory of Science and Technology on Communications University of Electronic Science and Technology of China

Multi-tap analog self-interference(SI) cancellation structures adopt parallel taps to reconstruct and then cancel SI in full-duplex radios. Each tap is usually comprised of one fixed delay line, one variable attenuator, and one optional variable phase shifter. To balance the quantity of the variable phase shifters and the achievable SI cancellation(SIC) performance, this paper proposes a novel analog SIC cancellation structure,called shared-phase-shifter constrained multi-tap structure(SMTS). In the proposed architecture, all taps share one phase shifter to emulate the dominated phase offset of the SI channel, which reduces the complexity of the implementation of the multi-tap analog SIC structure and avoids the SIC performance degradation. Then, the proposed SMTS and the existing structures are compared in terms of SIC performance and power ***, extensive simulations show that SMTS provides the close-to-optimal SIC performance as well as the lowest power dissipation relative to the existing multi-tap structures.

关键词： full-duplex multi-tap structure power dissipation phase shifter self-interference cancellation

Mitigating spectrum sensing data falsification attacks in hard-decision combining cooperative spectrum sensing

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Science China(Information Sciences) 2014年第4期57卷 192-200页

作者： ZENG Kun PENG QiHang tang youxi National Key Laboratory of Communications University of Electronic Science and Technology of China Communications Technology Laboratory Huawei Technologies Corporation Ltd. School of Communications and Information Engineering University of Electronic Science and Technology of China

In this paper we propose a simple yet robust secure cooperative spectrum sensing scheme with hard decision combining for Opportunistic Spectrum Access(OSA)*** on the historical sensing records and the assistance of trusted OSA nodes,the proposed approach effectively mitigates spectrum sensing data falsification attacks by excluding misbehaving OSA nodes from the process of *** analyses and numerical results are provided for various performance metrics,including overall detection *** of the proposed method with existing well-known secure spectrum sensing methods verifies the robustness and effectiveness of the proposed scheme.

关键词： cognitive radio networks opportunistic spectrum access spectrum sensing data falsification attacks network security

Self-mixed self-interference analog cancellation in full-duplex communications

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Science China(Information Sciences) 2016年第4期59卷 31-44页

作者： Hongtao LU Shihai SHAO Kai DENG youxi tang National Key Laboratory of Science and Technology on Communications University of Electronic Science and Technology of China Department of Physical Science and Electronic Engineering Yibin University

Rather than using existing self-interference cancellation methods, which essentially consist of reconstruction and subtraction, this paper proposes a novel approach, based on multiplication, to cancel selfinterference in the analog domain in full-duplex communications. This approach is called self-mixed selfinterference analog cancellation(SM-SIAC). Moreover, rather than using an individual analog cancellation circuit in existing self-interference cancellation methods, SM-SIAC can merge the analog cancellation circuit and the receiver. SM-SIAC is configured with three auto-tuning loops, consisting of one delay loop and two gain loops. SM-SIAC is further simplified with the Gaussian minimum shift keying(GMSK) self-interference *** these loops converge, the paper analyzes the cancellation capacity and derives a closed-form expression for the quadrature amplitude modulation self-interference signal and the GMSK self-interference signal. Simulation results illustrate the convergence of the gain loops and the cancellation capacity in the presence of engineering errors.

关键词： self-interference cancellation full-duplex self-mixed analog cancellation auto-tuning

Self-interference cancellation for cooperative jamming communications with nonideal alignment and channel equalization

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Science China(Information Sciences) 2021年第11期64卷 207-215页

作者： Wenbo GUO Yimin HE Hongzhi ZHAO Shihai SHAO youxi tang National Key Laboratory of Science and Technology on Communications University of Electronic Science and Technology of China

For the security of wireless communications, cooperative jamming can be used to intentionally degrade the signal-to-noise ratios received by eavesdroppers. Unfortunately, this jamming may also propagate to the legal receiver and then become a harmful self-interference(SI), which should be cancelled for reliable detection of the desired signal. In this paper, by comprehensively considering nonideal time-frequency alignment and channel equalization, SI-cancellation capability is investigated for the additive white Gaussian noise channel. Theoretical and simulation results demonstrated that the impact of the frequency alignment error is more serious than that of the time alignment and channel equalization errors. Moreover, it is illustrated that weaker SI power can tolerate a larger range of those nonidealities.

关键词： cooperative jamming self-interference time-frequency alignment channel equalization non-idealities

Analysis and Compensation of Frequency Offset in Co-Site Adjacent Channel Interference Suppression

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China Communications 2023年第6期20卷 116-128页

作者： Xiaolei Huo Wenbo Guo Ying Liu Hongzhi Zhao youxi tang National Key Laboratory of Science and Technology on Communications University of Electronic Science and Technology of ChinaChengdu 611731China Department of Electronic and Optical Engineering Shijiazhuang Campus of Army Engineering UniversityShijiazhuang 050003China

Due to the mismatch of the circuit oscillators,there will always be a frequency offset between the transmitter and the *** the adjacent channel interference(ACI)suppression system using the reconstruction and cancellation method,the frequency offset decreases the accuracy of the reconstructed signal and introduces a time-varying term in the interference cancellation,resulting in poor performance of the ACI *** this paper,the relationship between the normalized frequency offset,signal-to-noise ratio and the loss of interference suppression capability is analyzed through formula derivation and *** validity of the frequency offset compensation method based on the pilot sequence is verified,and the relationship between the sequence length and the estimation accuracy is *** paper provides necessary method reference and data support for the engineering of ACI suppression.

关键词： ACI non-linear distortion parameter estimation interference suppression

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Performance of an M-QAM full-duplex wireless system with a nonlinear amplifier

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Science China(Information Sciences) 2016年第10期59卷 103-111页

作者： Zhaojun HE Wanzhi MA Shihai SHAO Fei WU Chaojin QING youxi tang National Key Laboratory and Technology on Communications University of Electronic Science and Technology of China School of Electrical and Information Engineering Xihua University

The effect of amplifier nonlinearity is analyzed for M-QAM full-duplex communications in additive white Gaussian noise channels. Two classical memoryless nonlinear amplifier models, i.e., a traveling-wave tube amplifier and a solid-state power amplifier, are considered. An analytical expression for the bit error ratio is derived using a characteristic function and numerical integration. Theoretical results show perfect agreement with those obtained by simulation. The analytical results could be used to evaluate the degradation in performance of an M-QAM full-duplex system caused by amplifier nonlinearity, and will be helpful in finding the optimal static operating point of an amplifier.

关键词： full-duplex amplifier nonlinear distortion bit error ratio amplitude error phase error

Successive interference cancellation (SIC) in V-BLAST systems with asynchronous transmission mode

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Science in China(Series F) 2009年第12期52卷 2317-2323页

作者： LIN HuaJiong tang youxi GUAN Lu SHAO ShiHai National Key Lab of Communications University of Electronic Science and Technology of China Chengdu 610054 China

The V-BLAST system with asynchronous transmission mode first proposed by Shao can achieve full diversity only by using a simple linear detection scheme under zero forcing （ZF） criterion; therefore it gives a reasonable tradeoff between complexity and performance. In this paper, we propose two types of successive interference cancellation （SIC） detection schemes for the asynchronous V-BLAST system, one is characterized by applying Mr successive interference cancellators before a maximal ratio combiner （where Mr is the number of receive antennas）, and the other has a maximal ratio combiner before a successive interference cancellator. Since Type Ⅰ consumes more energy of the previously detected signals to recover a signal, Type Ⅱ can offer a better performance and simulations demonstrate its validity.

关键词： asynchronous transmission successive interference cancellation (SIC) vertical Bell Labs architecture of layered space-time (V-BLAST)

维普期刊数据库

Performance analysis of the nonlinear self-interference cancellation for full-duplex communications

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Science China(Information Sciences) 2022年第11期65卷 246-262页

作者： Nanzhou HU Shanghui XIAO Wensheng PAN Qiang XU Shihai SHAO youxi tang National Key Laboratory of Science and Technology on Communications University of Electronic Science and Technology of China

As the impairments of hardware circuits, such as the nonlinearities of power amplifiers(PAs),limit the self-interference suppression performance in full-duplex systems, nonlinear self-interference cancellation(SIC) has attracted much research attention. According to some existing studies, nonlinear SIC in full-duplex systems can be implemented with either nonlinear modeling or radio frequency(RF) signal feedback. However, to the best of our knowledge, there is no theoretical analysis and comparison of the cancellation performance with the two methods. In this paper, the performance of the digital nonlinear SIC with RF signal feedback and nonlinear modeling is analyzed and compared for the first time. The theoretical SIC capabilities of the two methods are derived, and the closed-form solutions are obtained. The factors affecting the performance of the two methods are discussed with the theoretical analysis. Then, by simulations, the theoretical results are verified and the performances of the nonlinear SIC with the two methods are compared in different environments.

关键词： full duplex self-interference cancellation PA nonlinearity digital domain performance analysis

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An enhanced digital predistortion algorithm based on polynomial model identification

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Science China(Information Sciences) 2019年第2期62卷 160-168页

作者： Wanzhi MA Xin QUAN Bo ZHAO Ying LIU Wensheng PAN Shihai SHAO youxi tang National Key Laboratory of Science and Technology on Communication University of Electronic Science and Technology of China Military Delegate Office in Shijiazhuang Military Delegate Bureau of Equipment Development Department

To improve the accuracy of the nonlinear distortion correction for the radio frequency(RF)power amplifier(PA), it is necessary to precisely obtain the reverse function of the PA nonlinear ***, the direct inversion of the PA nonlinear model involves solving a high-order univariate polynomial,which is difficult to apply in engineering. In this study, based on the envelope memory polynomial(EMP)model, the high-order terms of the nonlinear model are approximated by their previously calculated values through iterations and considered as known constants in the polynomial solution finding process, thereby resulting in a significant reduction in computational complexity. Compared with the direct inversion method,model of a 9 th-order nonlinear, the proposed method reduces the calculation time in the coordinated rotation digital computer(CORDIC) algorithm by at least 80%. The simulation results show that for a long-term evolution(LTE) downlink signal, the results obtained by the proposed simplified method agree well with those obtained by direct inversion method.

关键词： digital predistortion power amplifier nonlinear distortion memory effects radio frequency