To enable simultaneous transmit and receive(STAR)on the same frequency in a densely deployed space with multi-interference sources,this work proposes a digitally-assisted analog selfinterference cancellation method,wh...To enable simultaneous transmit and receive(STAR)on the same frequency in a densely deployed space with multi-interference sources,this work proposes a digitally-assisted analog selfinterference cancellation method,which can acquire reference signals through flexible wired/wireless switching access.Based on this method,the Minimum Mean Square Error algorithm with known channel state information is derived in detail,determining the upper limit of the cancellation performance,and the Adaptive Dithered Linear Search algorithm for real-time engineering cancellation is given.The correctness of theoretical analysis is verified by the practical self-interference channel measured by a vector network analyzer.Furthermore,we have designed and implemented the corresponding multiinterference cancellation prototype with the digitallyassisted structure,capable of handling multiple interferences(up to three)and supporting a large receive bandwidth of 100 MHz as well as a wide frequency coverage from 30 MHz to 3000 MHz.Prototype test results demonstrate that in the presence of three interferences,when the single interference bandwidth is 0.2/2/20 MHz(corresponding to the receive bandwidth of 2/20/100 MHz),the cancellation performance can reach 46/32/22 dB or more.展开更多
The adaptive filtering algorithm with a fixed projection order is unable to adjust its performance in response to changes in the external environment of airborne radars.To overcome this limitation,a new approach is in...The adaptive filtering algorithm with a fixed projection order is unable to adjust its performance in response to changes in the external environment of airborne radars.To overcome this limitation,a new approach is introduced,which is the variable projection order Ekblom norm-promoted adaptive algorithm(VPO-EPAA).The method begins by examining the mean squared deviation(MSD)of the EPAA,deriving a formula for its MSD.Next,it compares the MSD of EPAA at two different projection orders and selects the one that minimizes the MSD as the parameter for the current iteration.Furthermore,the algorithm’s computational complexity is analyzed theoretically.Simulation results from system identification and self-interference cancellation show that the proposed algorithm performs exceptionally well in airborne radar signal self-interference cancellation,even under various noise intensities and types of interference.展开更多
The in-band full-duplex(IBFD)mechanism is of interest in beyond 5 G systems due to its potential to enhance spectral efficiency and reduce delay.To achieve the maximum gain of IBFD systems,the significant self-interfe...The in-band full-duplex(IBFD)mechanism is of interest in beyond 5 G systems due to its potential to enhance spectral efficiency and reduce delay.To achieve the maximum gain of IBFD systems,the significant self-interference(SI)must be efficiently suppressed.The challenges of wideband selfinterference cancellation(SIC)lie in the radio frequency(RF)domain,where the performance will be limited by the hardware.This paper reviews current RF cancellation mechanisms and investigates an efficient mechanism for future wideband systems with minimum complexity.The working principle and implementation details of multi-tap cancellers are first introduced,then an optical domain-based RF canceller is reviewed,and a novel low-cost design is proposed.To minimize the cost and complexity of the canceller,the minimum required number of taps are analyzed.Simulation results show that with the commonly used 12-bits analog-to-digital converter(ADC)at the receiver,the novel optical domain-based canceller can enable efficient SIC in the 3 GPP LTE specifications compatible system within 400 MHz bandwidth.展开更多
In this paper,a general scheme in digital self-interference cancellation at baseband for zero-IF full-duplex transceivers is presented. We model the self-interference signals specifically with only the nonlinear disto...In this paper,a general scheme in digital self-interference cancellation at baseband for zero-IF full-duplex transceivers is presented. We model the self-interference signals specifically with only the nonlinear distortion signals falling in receiving band considered. A joint estimation algorithm is proposed for compensating the time delay and frequency offset taking into account the IQ amplitude and phase imbalances from mixers. The memory effect and nonlinear distortion are adaptively estimated by the de-correlated normalized least mean square(DNLMS) algorithm. Numerical simulation results demonstrate that the proposed self-interference cancellation scheme can efficiently compensate the self-interference and outperform the existing traditional solutions.展开更多
The 3-D beamforming scheme has elite as evolving interest because of its efficiency to empower assorted techniques such as vertical and horizontal domains and emanation beamforming according to subscriber's provis...The 3-D beamforming scheme has elite as evolving interest because of its efficiency to empower assorted techniques such as vertical and horizontal domains and emanation beamforming according to subscriber's provisions. Usually, 3-D beamforming communication is set up on FDD/TDD approach those effects on the performance of spectrum and energy efficiency. Co-frequency and CoTime Full Duplex(CCFD) is an effective solution to improve the spectrum and energy efficiency by transmitting and receiving simultaneously in frequency and time domain. While, CCFD communication often face the self-interference issue when communication occurs, simultaneously. Consequently, in this paper a self-interference elimination by physical feedback channel in CCFD for 3-D Beamforming communication scheme is proposed to improve the over-all system performance in terms of energy and spectrum efficiency. The simulation and analytical outcomes demonstrated that the proposed system is superior than the traditional one.展开更多
Full duplex radio increases the frequency efficiency but its performance is limited by the self-interference （SI）. We first analyze the multiple noises in the full duplex radio system and model such noises as an α ...Full duplex radio increases the frequency efficiency but its performance is limited by the self-interference （SI）. We first analyze the multiple noises in the full duplex radio system and model such noises as an α - stable distribution. Then we formulate a novel non-Gaussian SI problem. Under the maximum correntropy criterion （MCC）, a robust digital non-linear self-interference cancellation algorithm is proposed for the SI channel estimation. A gradient descent based algorithm is derived to search the optimal solution. Simulation results show that the proposed algorithm can achieve a smaller estimation error and a higher pseudo signal to interference plus noise ratio （PSINR） than the well-known least mean square （LMS） algorithm and least square （LS） algorithm.展开更多
In MIMO full duplex system,power amplifier(PA) nonlinearity limits the self-interference(SI) cancellation seriously. Most existing methods need to model and estimate the PA nonlinearity in order to reconstruct the SI,...In MIMO full duplex system,power amplifier(PA) nonlinearity limits the self-interference(SI) cancellation seriously. Most existing methods need to model and estimate the PA nonlinearity in order to reconstruct the SI,however the estimation error caused by the mismatch between the estimated PA model and the actual PA property still impacts the cancellation ability,especially when the transmit power is high. In this paper we propose a polarization oblique projection based self-interference cancellation method which does not need to estimate the PA nonlinearity coefficients. It exploits the polarization state information of the signals which is immune to the PA nonlinearity,and establishes an oblique projection operator to cancel the SI. Numerical results and analysis demonstrate that it can cancel the nonlinear SI effectively. Moreover the signal to interfere plus noise ratio(SINR) and the achievable sum rate do not deteriorate when the transmit power is high. Further,the upper bound of the achievable sum rate can be more than twice that of the half duplex.展开更多
We discuss the physical layer security scheme in the Full-Duplex(FD)MIMO point-to-point two-way communication system with residual self-interference,in which legitimate nodes send confidential information and null spa...We discuss the physical layer security scheme in the Full-Duplex(FD)MIMO point-to-point two-way communication system with residual self-interference,in which legitimate nodes send confidential information and null space Artificial Noise(AN)while receiving information.Because the Channel State Information(CSI)of the eavesdropper is unavailable,we optimize the covariance matrices of the information signal as well as the allocation of the antenna for transmitting and receiving to minimize the signal power consumption under the target rate constraint.As a result,the power of AN is maximized within the limit of total power,so the interception capability of the eavesdropper is suppressed as much as possible.Since self-interference cannot be completely eliminated,the optimization process of one legitimate node depends on the optimization result of the other.By substituting self-interference power in the secrecy rate formula with its average value,the joint optimization process at the two nodes is transformed into two separate and solvable optimization processes.Then,the Water-Filling Algorithm(WFA)and bisection algorithm are used to get the optimal covariance matrices of the signal.Furthermore,we derive the theoretical lower bound of ergodic achievable secrecy rate under rayleigh channels to evaluate the performance of the scheme.The simulation results show that the theoretical derivation is correct,and the actual achievable rate is very close to the target rate,which means that the approximation in the optimization is feasible.The results also show that secrecy transmission can be realized because a considerable secrecy rate can be achieved.展开更多
Adaptive digital self-interference cancellation(ADSIC)is a significant method to suppress self-interference and improve the performance of the linear frequency modulated continuous wave(LFMCW)radar.Due to efficient im...Adaptive digital self-interference cancellation(ADSIC)is a significant method to suppress self-interference and improve the performance of the linear frequency modulated continuous wave(LFMCW)radar.Due to efficient implementation structure,the conventional method based on least mean square(LMS)is widely used,but its performance is not sufficient for LFMCW radar.To achieve a better self-interference cancellation(SIC)result and more optimal radar performance,we present an ADSIC method based on fractional order LMS(FOLMS),which utilizes the multi-path cancellation structure and adaptively updates the weight coefficients of the cancellation system.First,we derive the iterative expression of the weight coefficients by using the fractional order derivative and short-term memory principle.Then,to solve the problem that it is difficult to select the parameters of the proposed method due to the non-stationary characteristics of radar transmitted signals,we construct the performance evaluation model of LFMCW radar,and analyze the relationship between the mean square deviation and the parameters of FOLMS.Finally,the theoretical analysis and simulation results show that the proposed method has a better SIC performance than the conventional methods.展开更多
This paper presents a design scheme of wire-line telephone system using self-interference(SI)cancellation technology in co-frequency co-time full-duplex(CCFD)system to realize absolute secure communication at the phys...This paper presents a design scheme of wire-line telephone system using self-interference(SI)cancellation technology in co-frequency co-time full-duplex(CCFD)system to realize absolute secure communication at the physical layer.This scheme can hide the target signal by skillfully releasing the high-power artificial noise to the whole link at the receiving node,and then make use of the receiver’s knowledge of the SI signal to achieve high dB SI cancellation with the help of analog domain SI cancellation technology in CCFD domain,so that the signal-to-noise ratio(SNR)received by the eavesdropper at any position of the link is far lower than that of the legitimate receiver,so as to realize the absolutely secure communication in the sense of Wyner principle.This paper not only puts forward the specific design scheme of absolutely secure communication telephone,but also analyzes the calculation of security capacity under different eavesdropping positions,different SI cancellation capability and different system parameters according to Shannon theory.展开更多
单频网(Single Frequency Network,SFN)的运行对发射机的同步提出极高的技术要求,任何同步误差都可能对网络性能产生不利影响。首先分析SFN中时间、频率和相位同步误差的定义与分类,其次探讨其对关键性能指标的影响机理,并量化同步误差...单频网(Single Frequency Network,SFN)的运行对发射机的同步提出极高的技术要求,任何同步误差都可能对网络性能产生不利影响。首先分析SFN中时间、频率和相位同步误差的定义与分类,其次探讨其对关键性能指标的影响机理,并量化同步误差对覆盖范围和信道容量的削弱程度,最后针对同步误差的成因提出提高授时源精度、优化参考时钟选型、改进同步跟踪环路设计及多径信号抑制等策略。展开更多
为提高LTE-Advanced系统小区边缘用户的吞吐量和用户体验,在现有协作多点传输(Coordinated Multi-Point,CoMP)方案基础上提出了两种CoMP系统的单频网(Sin-gle Frequency Network,SFN)预编码改进算法,以改善传统SFN预编码中信道合并的不...为提高LTE-Advanced系统小区边缘用户的吞吐量和用户体验,在现有协作多点传输(Coordinated Multi-Point,CoMP)方案基础上提出了两种CoMP系统的单频网(Sin-gle Frequency Network,SFN)预编码改进算法,以改善传统SFN预编码中信道合并的不确定性问题.第一种改进算法在发射端的部分传输节点处引入一个便于信道合并的相位参数,并按照合并后信道增益最大的准则确定相位参数的取值;第二种改进算法令部分传输节点的发射数据映射到天线时进行交换操作,同样按照信道增益最大准则确定交换方式.仿真结果表明,两种改进算法能有效提高小区边缘用户的谱效率,且能适用于相干/非相干信道及低/高秩信道的情况.展开更多
基金supported in part by the National Natural Science Foundation of China under Grant 62071094in part by the National Key Laboratory of Wireless Communications Foundation under Grant IFN202402in part by the Postdoctoral Fellowship Program(Grade C)of China Postdoctoral Science Foundation under Grant GZC20240217.
文摘To enable simultaneous transmit and receive(STAR)on the same frequency in a densely deployed space with multi-interference sources,this work proposes a digitally-assisted analog selfinterference cancellation method,which can acquire reference signals through flexible wired/wireless switching access.Based on this method,the Minimum Mean Square Error algorithm with known channel state information is derived in detail,determining the upper limit of the cancellation performance,and the Adaptive Dithered Linear Search algorithm for real-time engineering cancellation is given.The correctness of theoretical analysis is verified by the practical self-interference channel measured by a vector network analyzer.Furthermore,we have designed and implemented the corresponding multiinterference cancellation prototype with the digitallyassisted structure,capable of handling multiple interferences(up to three)and supporting a large receive bandwidth of 100 MHz as well as a wide frequency coverage from 30 MHz to 3000 MHz.Prototype test results demonstrate that in the presence of three interferences,when the single interference bandwidth is 0.2/2/20 MHz(corresponding to the receive bandwidth of 2/20/100 MHz),the cancellation performance can reach 46/32/22 dB or more.
基金supported by the Shan⁃dong Provincial Natural Science Foundation(No.ZR2022MF314).
文摘The adaptive filtering algorithm with a fixed projection order is unable to adjust its performance in response to changes in the external environment of airborne radars.To overcome this limitation,a new approach is introduced,which is the variable projection order Ekblom norm-promoted adaptive algorithm(VPO-EPAA).The method begins by examining the mean squared deviation(MSD)of the EPAA,deriving a formula for its MSD.Next,it compares the MSD of EPAA at two different projection orders and selects the one that minimizes the MSD as the parameter for the current iteration.Furthermore,the algorithm’s computational complexity is analyzed theoretically.Simulation results from system identification and self-interference cancellation show that the proposed algorithm performs exceptionally well in airborne radar signal self-interference cancellation,even under various noise intensities and types of interference.
基金supported by the research grant from Huawei Technologies(Sweden)ABsupported by the U.K.Engineering and Physical Sciences Research Council(EPSRC)under Grant EP/P009549/1。
文摘The in-band full-duplex(IBFD)mechanism is of interest in beyond 5 G systems due to its potential to enhance spectral efficiency and reduce delay.To achieve the maximum gain of IBFD systems,the significant self-interference(SI)must be efficiently suppressed.The challenges of wideband selfinterference cancellation(SIC)lie in the radio frequency(RF)domain,where the performance will be limited by the hardware.This paper reviews current RF cancellation mechanisms and investigates an efficient mechanism for future wideband systems with minimum complexity.The working principle and implementation details of multi-tap cancellers are first introduced,then an optical domain-based RF canceller is reviewed,and a novel low-cost design is proposed.To minimize the cost and complexity of the canceller,the minimum required number of taps are analyzed.Simulation results show that with the commonly used 12-bits analog-to-digital converter(ADC)at the receiver,the novel optical domain-based canceller can enable efficient SIC in the 3 GPP LTE specifications compatible system within 400 MHz bandwidth.
基金supported in part by the National Natural Science Foundation of China(No.61601027)
文摘In this paper,a general scheme in digital self-interference cancellation at baseband for zero-IF full-duplex transceivers is presented. We model the self-interference signals specifically with only the nonlinear distortion signals falling in receiving band considered. A joint estimation algorithm is proposed for compensating the time delay and frequency offset taking into account the IQ amplitude and phase imbalances from mixers. The memory effect and nonlinear distortion are adaptively estimated by the de-correlated normalized least mean square(DNLMS) algorithm. Numerical simulation results demonstrate that the proposed self-interference cancellation scheme can efficiently compensate the self-interference and outperform the existing traditional solutions.
基金supported by National Natural Science Foundation of China (Nos.61172107,61172110)National High Technical Research and Development Program (863 Program) of China (No.2015AA016306)+1 种基金Major Projects in Liaoning Province Science and Technology Innovation (No.201302001)Fundamental Research Funds for the Central Universities of China (No.DUT13LAB06)
文摘The 3-D beamforming scheme has elite as evolving interest because of its efficiency to empower assorted techniques such as vertical and horizontal domains and emanation beamforming according to subscriber's provisions. Usually, 3-D beamforming communication is set up on FDD/TDD approach those effects on the performance of spectrum and energy efficiency. Co-frequency and CoTime Full Duplex(CCFD) is an effective solution to improve the spectrum and energy efficiency by transmitting and receiving simultaneously in frequency and time domain. While, CCFD communication often face the self-interference issue when communication occurs, simultaneously. Consequently, in this paper a self-interference elimination by physical feedback channel in CCFD for 3-D Beamforming communication scheme is proposed to improve the over-all system performance in terms of energy and spectrum efficiency. The simulation and analytical outcomes demonstrated that the proposed system is superior than the traditional one.
基金supported by the National Natural Science Foundation of China under Grants 61372092"863" Program under Grants 2014AA01A701
文摘Full duplex radio increases the frequency efficiency but its performance is limited by the self-interference （SI）. We first analyze the multiple noises in the full duplex radio system and model such noises as an α - stable distribution. Then we formulate a novel non-Gaussian SI problem. Under the maximum correntropy criterion （MCC）, a robust digital non-linear self-interference cancellation algorithm is proposed for the SI channel estimation. A gradient descent based algorithm is derived to search the optimal solution. Simulation results show that the proposed algorithm can achieve a smaller estimation error and a higher pseudo signal to interference plus noise ratio （PSINR） than the well-known least mean square （LMS） algorithm and least square （LS） algorithm.
基金supported by the National Natural Science Foundations of China under Grant No.61501050 and No.61271177
文摘In MIMO full duplex system,power amplifier(PA) nonlinearity limits the self-interference(SI) cancellation seriously. Most existing methods need to model and estimate the PA nonlinearity in order to reconstruct the SI,however the estimation error caused by the mismatch between the estimated PA model and the actual PA property still impacts the cancellation ability,especially when the transmit power is high. In this paper we propose a polarization oblique projection based self-interference cancellation method which does not need to estimate the PA nonlinearity coefficients. It exploits the polarization state information of the signals which is immune to the PA nonlinearity,and establishes an oblique projection operator to cancel the SI. Numerical results and analysis demonstrate that it can cancel the nonlinear SI effectively. Moreover the signal to interfere plus noise ratio(SINR) and the achievable sum rate do not deteriorate when the transmit power is high. Further,the upper bound of the achievable sum rate can be more than twice that of the half duplex.
基金This work was supported by the National Nature Science Foundation of China(No.61971080,No.61471076)Chongqing Research Program of Basic Research and Frontier Exploration(No.cstc2018jcyjAX0432)the Key Project of Science and Technology Research of Chongqing Education Commission(No.KJZD-K201800603,No.KJZD-M201900602).
文摘We discuss the physical layer security scheme in the Full-Duplex(FD)MIMO point-to-point two-way communication system with residual self-interference,in which legitimate nodes send confidential information and null space Artificial Noise(AN)while receiving information.Because the Channel State Information(CSI)of the eavesdropper is unavailable,we optimize the covariance matrices of the information signal as well as the allocation of the antenna for transmitting and receiving to minimize the signal power consumption under the target rate constraint.As a result,the power of AN is maximized within the limit of total power,so the interception capability of the eavesdropper is suppressed as much as possible.Since self-interference cannot be completely eliminated,the optimization process of one legitimate node depends on the optimization result of the other.By substituting self-interference power in the secrecy rate formula with its average value,the joint optimization process at the two nodes is transformed into two separate and solvable optimization processes.Then,the Water-Filling Algorithm(WFA)and bisection algorithm are used to get the optimal covariance matrices of the signal.Furthermore,we derive the theoretical lower bound of ergodic achievable secrecy rate under rayleigh channels to evaluate the performance of the scheme.The simulation results show that the theoretical derivation is correct,and the actual achievable rate is very close to the target rate,which means that the approximation in the optimization is feasible.The results also show that secrecy transmission can be realized because a considerable secrecy rate can be achieved.
文摘Adaptive digital self-interference cancellation(ADSIC)is a significant method to suppress self-interference and improve the performance of the linear frequency modulated continuous wave(LFMCW)radar.Due to efficient implementation structure,the conventional method based on least mean square(LMS)is widely used,but its performance is not sufficient for LFMCW radar.To achieve a better self-interference cancellation(SIC)result and more optimal radar performance,we present an ADSIC method based on fractional order LMS(FOLMS),which utilizes the multi-path cancellation structure and adaptively updates the weight coefficients of the cancellation system.First,we derive the iterative expression of the weight coefficients by using the fractional order derivative and short-term memory principle.Then,to solve the problem that it is difficult to select the parameters of the proposed method due to the non-stationary characteristics of radar transmitted signals,we construct the performance evaluation model of LFMCW radar,and analyze the relationship between the mean square deviation and the parameters of FOLMS.Finally,the theoretical analysis and simulation results show that the proposed method has a better SIC performance than the conventional methods.
基金Supported by the Natural Science Foundation of Hubei Province(2019CFB593)the National Natural Science Foundation of China(61961016)+1 种基金Ph.D.Research Start-up Foundation of Hubei Minzu University(MY2018B08)Graduate Education Innovation Plan of Hubei Minzu University(DC2000000119)。
文摘This paper presents a design scheme of wire-line telephone system using self-interference(SI)cancellation technology in co-frequency co-time full-duplex(CCFD)system to realize absolute secure communication at the physical layer.This scheme can hide the target signal by skillfully releasing the high-power artificial noise to the whole link at the receiving node,and then make use of the receiver’s knowledge of the SI signal to achieve high dB SI cancellation with the help of analog domain SI cancellation technology in CCFD domain,so that the signal-to-noise ratio(SNR)received by the eavesdropper at any position of the link is far lower than that of the legitimate receiver,so as to realize the absolutely secure communication in the sense of Wyner principle.This paper not only puts forward the specific design scheme of absolutely secure communication telephone,but also analyzes the calculation of security capacity under different eavesdropping positions,different SI cancellation capability and different system parameters according to Shannon theory.
文摘单频网(Single Frequency Network,SFN)的运行对发射机的同步提出极高的技术要求,任何同步误差都可能对网络性能产生不利影响。首先分析SFN中时间、频率和相位同步误差的定义与分类,其次探讨其对关键性能指标的影响机理,并量化同步误差对覆盖范围和信道容量的削弱程度,最后针对同步误差的成因提出提高授时源精度、优化参考时钟选型、改进同步跟踪环路设计及多径信号抑制等策略。
文摘为提高LTE-Advanced系统小区边缘用户的吞吐量和用户体验,在现有协作多点传输(Coordinated Multi-Point,CoMP)方案基础上提出了两种CoMP系统的单频网(Sin-gle Frequency Network,SFN)预编码改进算法,以改善传统SFN预编码中信道合并的不确定性问题.第一种改进算法在发射端的部分传输节点处引入一个便于信道合并的相位参数,并按照合并后信道增益最大的准则确定相位参数的取值;第二种改进算法令部分传输节点的发射数据映射到天线时进行交换操作,同样按照信道增益最大准则确定交换方式.仿真结果表明,两种改进算法能有效提高小区边缘用户的谱效率,且能适用于相干/非相干信道及低/高秩信道的情况.
