A new channel estimation and data detection joint algorithm is proposed for multi-input multi-output （MIMO） - orthogonal frequency division multiplexing （OFDM） system using linear minimum mean square error （LMMSE...A new channel estimation and data detection joint algorithm is proposed for multi-input multi-output （MIMO） - orthogonal frequency division multiplexing （OFDM） system using linear minimum mean square error （LMMSE）- based space-alternating generalized expectation-maximization （SAGE） algorithm. In the proposed algorithm, every sub-frame of the MIMO-OFDM system is divided into some OFDM sub-blocks and the LMMSE-based SAGE algorithm in each sub-block is used. At the head of each sub-flame, we insert training symbols which are used in the initial estimation at the beginning. Channel estimation of the previous sub-block is applied to the initial estimation in the current sub-block by the maximum-likelihood （ML） detection to update channel estimatjon and data detection by iteration until converge. Then all the sub-blocks can be finished in turn. Simulation results show that the proposed algorithm can improve the bit error rate （BER） performance.展开更多
Aiming at the problem of high computational complexity of Vertical-BLAST(V-BLAST) algorithm in Multiple-Input Multiple-Output-Orthogonal Frequency Division Multiplexing(MIMO-OFDM) system signal detection, this paper f...Aiming at the problem of high computational complexity of Vertical-BLAST(V-BLAST) algorithm in Multiple-Input Multiple-Output-Orthogonal Frequency Division Multiplexing(MIMO-OFDM) system signal detection, this paper first uses Sorted QR Decomposition(SQRD) iterative operation instead of matrix inversion to reduce the computational complexity of the algorithm, and then considering that the algorithm is greatly affected by noise, Minimum Mean Square Error(MMSE) criterion is used to weaken the noise effect. At the same time, in order to reduce the noise and computational complexity, MMSE and SQRD are combined, which can not only reduce the noise and computational complexity, but also obtain the sub-optimal detection order, thus improving the detection performance of the MIMO-OFDM system. Finally, the numerical simulation of the MMSE-SQRD detection algorithm is carried out. The results show that the Eb/No of MMSE-SQRD algorithm is 2 dB greater than that of the MMSE algorithm and the computational complexity is O(NT3) under the conditions that NT =NR=2 and the BER is 10–2. The detection algorithm satisfies the demand of short wave and wideband wireless communication.展开更多
The matrix inversion operation is needed in the MMSE decoding algorithm of orthogonal space-time block coding （OSTBC） proposed by Papadias and Foschini. In this paper, an minimum mean square error （MMSE） decoding ...The matrix inversion operation is needed in the MMSE decoding algorithm of orthogonal space-time block coding （OSTBC） proposed by Papadias and Foschini. In this paper, an minimum mean square error （MMSE） decoding algorithm without matrix inversion is proposed, by which the computational complexity can be reduced directly but the decoding performance is not affected.展开更多
在采用多天线高阶QAM的MIMO通信系统中,现有基于信道分组并行检测算法虽然接近最优检测性能但以牺牲计算效率为代价.针对这一问题,本文提出一种MMSE准则下基于信道分组的并行检测算法,不但有效降低计算复杂度,而且仍保证检测性能.该算...在采用多天线高阶QAM的MIMO通信系统中,现有基于信道分组并行检测算法虽然接近最优检测性能但以牺牲计算效率为代价.针对这一问题,本文提出一种MMSE准则下基于信道分组的并行检测算法,不但有效降低计算复杂度,而且仍保证检测性能.该算法采用MMSE准则下格归约算法改进分组后条件较好子信道矩阵特性,并在消除参考信号基础上利用改进的子信道矩阵对剩余信号以非线性方式进行检测.仿真结果表明:对4@4和6@6MIMO系统,该算法检测性能达到最优,对于8@8 MIMO系统,比最优算法所需信噪比提高约1dB.复杂度分析表明:相比现有信道分组检测算法,相同检测性能下该算法在6@6 M IMO系统中复杂度降低90%以上,在8@8 MIMO系统中复杂度降低98%以上.展开更多
干扰对齐(IA)是一种有效消除干扰的管理机制。为了彻底消除干扰信号对期望信号的影响,通过预编码技术处理使干扰在接收端重叠,使接收端的干扰信号与期望信号有效分开。在传统最小均方误差(Minimum Mean Square Error,MMSE)算法和最小二...干扰对齐(IA)是一种有效消除干扰的管理机制。为了彻底消除干扰信号对期望信号的影响,通过预编码技术处理使干扰在接收端重叠,使接收端的干扰信号与期望信号有效分开。在传统最小均方误差(Minimum Mean Square Error,MMSE)算法和最小二乘(least square,LS)算法基础上,提出基于符号检测辅助的最小均方误差(Symbol Detection Aided Minimum Mean Square Error,SDA-MMSE)算法和最小二乘(Symbol Detection Aided Least Square,SDA-LS)算法。分别基于传统算法和改进算法进行迭代计算,通过仿真可看出SDA-MMSE算法的MSE较SDA-LS算法的MSE降低约20%。理论分析与仿真结果表明,改进算法较传统算法具有更好的系统性能,且SDA-MMSE算法系统性能最优。展开更多
Linear minimum mean square error(MMSE)detection has been shown to achieve near-optimal performance for massive multiple-input multiple-output(MIMO)systems but inevitably involves complicated matrix inversion,which ent...Linear minimum mean square error(MMSE)detection has been shown to achieve near-optimal performance for massive multiple-input multiple-output(MIMO)systems but inevitably involves complicated matrix inversion,which entails high complexity.To avoid the exact matrix inversion,a considerable number of implicit and explicit approximate matrix inversion based detection methods is proposed.By combining the advantages of both the explicit and the implicit matrix inversion,this paper introduces a new low-complexity signal detection algorithm.Firstly,the relationship between implicit and explicit techniques is analyzed.Then,an enhanced Newton iteration method is introduced to realize an approximate MMSE detection for massive MIMO uplink systems.The proposed improved Newton iteration significantly reduces the complexity of conventional Newton iteration.However,its complexity is still high for higher iterations.Thus,it is applied only for first two iterations.For subsequent iterations,we propose a novel trace iterative method(TIM)based low-complexity algorithm,which has significantly lower complexity than higher Newton iterations.Convergence guarantees of the proposed detector are also provided.Numerical simulations verify that the proposed detector exhibits significant performance enhancement over recently reported iterative detectors and achieves close-to-MMSE performance while retaining the low-complexity advantage for systems with hundreds of antennas.展开更多
The detection performance is evaluated for our proposed analog multiuser receiver in Ultra-WideBand (UWB) transmitted-reference system. In the presence of dense multipath and multi-access signals,the performance analy...The detection performance is evaluated for our proposed analog multiuser receiver in Ultra-WideBand (UWB) transmitted-reference system. In the presence of dense multipath and multi-access signals,the performance analysis is difficult due to the complicated waveform of received impulse. We develop an approach to analyze the steady-state Signal-to-Interference-plus-Noise (SINR) of the detector output. The multipath-spread impulse is fitted to an exponentially decaying profile in the analysis. A closed-form expression of steady-state SINR is further deduced for the proposed Least Minimum Square (LMS) detector. The analysis is validated by simulations in Line-Of-Sight (LOS) and Non-Line-Of-Sight (NLOS) channel respectively. Based on the theoretical results,the multipath delay spread is employed to determine the optimal width of the integration window of the detector.展开更多
针对以感知波形为基础的信号在通感一体化(Integrated sensing and communication,ISAC)系统中面临通信速率低、易被截获等问题,本文设计了一种基于正交相移键控(Quadrature phase shift keying,QPSK)与线性调频信号(Linear frequency m...针对以感知波形为基础的信号在通感一体化(Integrated sensing and communication,ISAC)系统中面临通信速率低、易被截获等问题,本文设计了一种基于正交相移键控(Quadrature phase shift keying,QPSK)与线性调频信号(Linear frequency modulation,LFM)的多路跳频传输架构。该架构利用多个LFM信号同时在重叠的频谱区间传输以提高符号速率,并通过LFM子载波的跳频特性实现加密通信。此外,通过结合动态前导码与数据的时分复用机制,该方案有效地提升了多路LFM信号的路径索引和参数估计精度。针对符号解调,本文提出两种基于非相干离散啁啾傅里叶变换(Noncoherent discrete chirp Fourier transform,NC⁃DCFT)的多峰值检测算法。仿真结果表明,在相同符号速率约束下,本文所提出的多路并行架构在误码率方面优于传统单路方案,当信噪比为0 dB时,4路并行架构的误码率相较于单路方案降低了一个数量级。同时,动态前导码方案满足不同场景下的路径索引识别需求,在信噪比为0 dB时,归一化均方差均低于10-2。此外,面向功率均衡、功率差异显著及载波参数保护间隔较小3种复杂场景设计的符号检测算法,在其适配场景下均可实现误码率低于10-2。最后,跳频机制显著增强了系统的抗截获能力,即使50%参数泄露,第3方对信号的恢复概率(Probability of accurate recovery,PAR)仍被压制在7%以下,验证了该方案的鲁棒性与应用价值。展开更多
基金Supported by the National Natural Science Foundation of China （No. 61001105）, the National Science and Technology Major Projects （No. 2011ZX03001- 007- 03） and Beijing Natural Science Foundation （No. 4102043）.
文摘A new channel estimation and data detection joint algorithm is proposed for multi-input multi-output （MIMO） - orthogonal frequency division multiplexing （OFDM） system using linear minimum mean square error （LMMSE）- based space-alternating generalized expectation-maximization （SAGE） algorithm. In the proposed algorithm, every sub-frame of the MIMO-OFDM system is divided into some OFDM sub-blocks and the LMMSE-based SAGE algorithm in each sub-block is used. At the head of each sub-flame, we insert training symbols which are used in the initial estimation at the beginning. Channel estimation of the previous sub-block is applied to the initial estimation in the current sub-block by the maximum-likelihood （ML） detection to update channel estimatjon and data detection by iteration until converge. Then all the sub-blocks can be finished in turn. Simulation results show that the proposed algorithm can improve the bit error rate （BER） performance.
基金Supported by the National Natural Science Foundation of China(61671333)
文摘Aiming at the problem of high computational complexity of Vertical-BLAST(V-BLAST) algorithm in Multiple-Input Multiple-Output-Orthogonal Frequency Division Multiplexing(MIMO-OFDM) system signal detection, this paper first uses Sorted QR Decomposition(SQRD) iterative operation instead of matrix inversion to reduce the computational complexity of the algorithm, and then considering that the algorithm is greatly affected by noise, Minimum Mean Square Error(MMSE) criterion is used to weaken the noise effect. At the same time, in order to reduce the noise and computational complexity, MMSE and SQRD are combined, which can not only reduce the noise and computational complexity, but also obtain the sub-optimal detection order, thus improving the detection performance of the MIMO-OFDM system. Finally, the numerical simulation of the MMSE-SQRD detection algorithm is carried out. The results show that the Eb/No of MMSE-SQRD algorithm is 2 dB greater than that of the MMSE algorithm and the computational complexity is O(NT3) under the conditions that NT =NR=2 and the BER is 10–2. The detection algorithm satisfies the demand of short wave and wideband wireless communication.
文摘The matrix inversion operation is needed in the MMSE decoding algorithm of orthogonal space-time block coding （OSTBC） proposed by Papadias and Foschini. In this paper, an minimum mean square error （MMSE） decoding algorithm without matrix inversion is proposed, by which the computational complexity can be reduced directly but the decoding performance is not affected.
文摘在采用多天线高阶QAM的MIMO通信系统中,现有基于信道分组并行检测算法虽然接近最优检测性能但以牺牲计算效率为代价.针对这一问题,本文提出一种MMSE准则下基于信道分组的并行检测算法,不但有效降低计算复杂度,而且仍保证检测性能.该算法采用MMSE准则下格归约算法改进分组后条件较好子信道矩阵特性,并在消除参考信号基础上利用改进的子信道矩阵对剩余信号以非线性方式进行检测.仿真结果表明:对4@4和6@6MIMO系统,该算法检测性能达到最优,对于8@8 MIMO系统,比最优算法所需信噪比提高约1dB.复杂度分析表明:相比现有信道分组检测算法,相同检测性能下该算法在6@6 M IMO系统中复杂度降低90%以上,在8@8 MIMO系统中复杂度降低98%以上.
文摘干扰对齐(IA)是一种有效消除干扰的管理机制。为了彻底消除干扰信号对期望信号的影响,通过预编码技术处理使干扰在接收端重叠,使接收端的干扰信号与期望信号有效分开。在传统最小均方误差(Minimum Mean Square Error,MMSE)算法和最小二乘(least square,LS)算法基础上,提出基于符号检测辅助的最小均方误差(Symbol Detection Aided Minimum Mean Square Error,SDA-MMSE)算法和最小二乘(Symbol Detection Aided Least Square,SDA-LS)算法。分别基于传统算法和改进算法进行迭代计算,通过仿真可看出SDA-MMSE算法的MSE较SDA-LS算法的MSE降低约20%。理论分析与仿真结果表明,改进算法较传统算法具有更好的系统性能,且SDA-MMSE算法系统性能最优。
基金supported by National Natural Science Foundation of China(62371225,62371227)。
文摘Linear minimum mean square error(MMSE)detection has been shown to achieve near-optimal performance for massive multiple-input multiple-output(MIMO)systems but inevitably involves complicated matrix inversion,which entails high complexity.To avoid the exact matrix inversion,a considerable number of implicit and explicit approximate matrix inversion based detection methods is proposed.By combining the advantages of both the explicit and the implicit matrix inversion,this paper introduces a new low-complexity signal detection algorithm.Firstly,the relationship between implicit and explicit techniques is analyzed.Then,an enhanced Newton iteration method is introduced to realize an approximate MMSE detection for massive MIMO uplink systems.The proposed improved Newton iteration significantly reduces the complexity of conventional Newton iteration.However,its complexity is still high for higher iterations.Thus,it is applied only for first two iterations.For subsequent iterations,we propose a novel trace iterative method(TIM)based low-complexity algorithm,which has significantly lower complexity than higher Newton iterations.Convergence guarantees of the proposed detector are also provided.Numerical simulations verify that the proposed detector exhibits significant performance enhancement over recently reported iterative detectors and achieves close-to-MMSE performance while retaining the low-complexity advantage for systems with hundreds of antennas.
基金Supported by the Guangxi Natural Science Foundation (No.0731025, No.0731026)the Established Project by Guangxi Education Department (No.200808LX117)
文摘The detection performance is evaluated for our proposed analog multiuser receiver in Ultra-WideBand (UWB) transmitted-reference system. In the presence of dense multipath and multi-access signals,the performance analysis is difficult due to the complicated waveform of received impulse. We develop an approach to analyze the steady-state Signal-to-Interference-plus-Noise (SINR) of the detector output. The multipath-spread impulse is fitted to an exponentially decaying profile in the analysis. A closed-form expression of steady-state SINR is further deduced for the proposed Least Minimum Square (LMS) detector. The analysis is validated by simulations in Line-Of-Sight (LOS) and Non-Line-Of-Sight (NLOS) channel respectively. Based on the theoretical results,the multipath delay spread is employed to determine the optimal width of the integration window of the detector.
文摘针对以感知波形为基础的信号在通感一体化(Integrated sensing and communication,ISAC)系统中面临通信速率低、易被截获等问题,本文设计了一种基于正交相移键控(Quadrature phase shift keying,QPSK)与线性调频信号(Linear frequency modulation,LFM)的多路跳频传输架构。该架构利用多个LFM信号同时在重叠的频谱区间传输以提高符号速率,并通过LFM子载波的跳频特性实现加密通信。此外,通过结合动态前导码与数据的时分复用机制,该方案有效地提升了多路LFM信号的路径索引和参数估计精度。针对符号解调,本文提出两种基于非相干离散啁啾傅里叶变换(Noncoherent discrete chirp Fourier transform,NC⁃DCFT)的多峰值检测算法。仿真结果表明,在相同符号速率约束下,本文所提出的多路并行架构在误码率方面优于传统单路方案,当信噪比为0 dB时,4路并行架构的误码率相较于单路方案降低了一个数量级。同时,动态前导码方案满足不同场景下的路径索引识别需求,在信噪比为0 dB时,归一化均方差均低于10-2。此外,面向功率均衡、功率差异显著及载波参数保护间隔较小3种复杂场景设计的符号检测算法,在其适配场景下均可实现误码率低于10-2。最后,跳频机制显著增强了系统的抗截获能力,即使50%参数泄露,第3方对信号的恢复概率(Probability of accurate recovery,PAR)仍被压制在7%以下,验证了该方案的鲁棒性与应用价值。
