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东南大学学报（自然科学版） 2024年第4期54卷 961-971页

作者：黄永明王正东南大学移动通信国家重点实验室南京211189 东南大学信息科学与工程学院南京211189

为了提升大规模MIMO系统的信号检测性能,对由投影和梯度下降(gradient descent,GD)这2个基础操作构成的投影梯度下降(projected gradient descent,PGD)算法进行研究.在基于PGD算法的大规模MIMO检测器中,由于投影和GD操作的损失函数不同... 详细信息

为了提升大规模MIMO系统的信号检测性能,对由投影和梯度下降(gradient descent,GD)这2个基础操作构成的投影梯度下降(projected gradient descent,PGD)算法进行研究.在基于PGD算法的大规模MIMO检测器中,由于投影和GD操作的损失函数不同,迭代时需要使两者达到平衡,因此通过广义投影梯度下降(generalized projected gradient descent,GPGD)方法实现了投影和GD操作的灵活选取.GPGD方法中在多次的GD步骤后执行1次投影,与传统方式中交替进行投影和GD操作相比,具有显著优势;同时为了保证算法的收敛效率,也对GD操作的步长进行了探究.另外,通过对GPGD算法进行基于深度神经网络的迭代展开,进一步构建了自纠错自动检测器的检测框架,有效提升检测性能和效率.仿真结果表明,GPGD方法带来了明显的系统增益,具有显著的优越性.

关键词：大规模MIMO检测投影梯度下降去噪自动编码器深度学习

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Constrained least squares algorithm for channel vector estimation in 2-D RAKE receiver

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Journal of Southeast University(English Edition) 2003年第1期19卷 1-4页

作者：王建明赵春明东南大学移动通信国家重点实验室南京210096

Based on the fact that the variation of tile direction of arrival (DOA) isslower than that of the channel fading, the steering vector of the desired signal is estimatedfirstly using a subspace decomposition method and then a constrained condition is *** signals are further employed to estimate the channel vector based on the constrained leastsquares criterion. We use the iterative least squares with projection (ILSP) algorithm initializedby the pilot to get the estimation. The accuracy of channel estimation and symbol detection can beprogressively increased through the iteration procedure of the ILSP algorithm. Simulation resultsdemonstrate that the proposed algorithm improves the system performance effectively compared withthe conventional 2-D RAKE receiver.

关键词： 2-D RAKE receiver channel estimation subspace decomposition constrained least squares

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Low complexity iterative differential decoding algorithm for multiband UWB communication systems

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Journal of Southeast University(English Edition) 2007年第1期23卷 7-11页

作者：金秀峰毕光国肖海勇东南大学移动通信国家重点实验室南京210096

Due to not requiring channel state information （CSI） at both the transmitter and the receiver, noncoherent ultra-wideband （UWB） incurs a performance penalty of approximately 3 dB in the required signal to noise ratio （SNR） compared to the coherent case. To overcome the gap, an effective differential encoding and decoding scheme for multiband UWB systems is proposed. The proposed scheme employs the parallel concatenation of two recursive differential unitary space-frequency encoders at the transmitter. At the receiver, two component decoders iteratively decode information bits by interchanging soft metric values between each other. To reduce the computation complexity, a decoding algorithm which only uses transition probability to calculate the log likelihood ratios （LLRs） for the decoded bits is given. Simulation results show that the proposed scheme can dramatically outperform the conventional differential and even coherent detection at high SNR with a few iterations.

关键词： multiband UWB multiple-input multiple-output （MIMO） system noncoherent detection group code iterative decoding

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Partial transmitting sequence method based on trellis factor search

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Journal of Southeast University(English Edition) 2005年第2期21卷 123-126页

作者：吴炳洋程时昕东南大学移动通信国家重点实验室南京210096

To obtain good trade-offs between complexity and performance onpeak-to-average power ratio (PAPR) reduction in orthogonal frequency division multiplexing (OFDM)using partial transmitting sequence (PTS) schemes, a trellis structure based PTS factor searchmethod is proposed. The trellis search is with a variant constraint length L_C, 1 ≤ L_C ≤ V-1,where V is the number of PTS subblocks. The method is to decide a PTS factor by searching all thepossible paths obtained by varying L_C consecutive factors. The trellis search can be viewed as ageneral PTS factor search model. If L_C = V-1, it is a full search, and if L_C = 1, it is aniterative search. Using different constraint lengths, trellis factor search PTS exhibits differentPAPR reduction performances. A larger L_C results in a better performance and L_C = V-1 results inthe optimum. However, a larger L_C requires more computation. This helps to choose a good trade-offbetween complexity and performance.

关键词： peak-to-average power ratio (PAPR) partial transmitting sequence (PTS) trellis search

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Achievability of Chong-Motani-Garg relay channel capacity bounds using forward decoding

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Journal of Southeast University(English Edition) 2009年第1期25卷 6-8页

作者：张源东南大学移动通信国家重点实验室南京210096

To reduce decoding delay of a communication scheme which is backward-decoding-based and achievable Chong Motani-Garg capacity bounds, a novel forward-sliding-window decoding-based communication scheme is proposed. In this scheme, if w = （w1, w2） is the message to be sent in block b, the relay will decode message w1 and generate a new message z at the end of block b, and the receiver will decode message w1 at the end of block b ＋ 1 and decode message z and w2 at the end of block b ＋ 2. Analysis results show that this new communication scheme can achieve the same Chong-Motani-Garg bounds and the decoding delay is only two blocks which is much shorter than that of backward decoding. Therefore, Chong-Motani-Garg bounds can be achieved by a forward decoding-based communication scheme with short decoding delay.

关键词： achievable rate capacity backward decoding forward decoding mixed strategy relay channel

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Co-channel interference rejection for MIMO-OFDM systems

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Journal of Southeast University(English Edition) 2015年第2期31卷 170-174页

作者：潘云强孟鑫江彬高西奇东南大学移动通信国家重点实验室南京210096

A method based on the maximum a posteriori probability （MAP） criterion is proposed to estimate the channel frequency response （CFR） matrix and interference- plus-noise spatial covariance matrix （SCM） for multiple input and multiple output orthogonal frequency division multiplexing （MIMO-OFDM） systems. An iterative solution is proposed to solve the MAP-based problem and an interference rejection combining （IRC） receiver is derived to suppress co-channel interference （CCI） based on the estimated CFR and SCM. Furthermore, considering the property of SCM, i. e., Hermitian and semi-definite, two schemes are proposed to improve the accuracy of SCM estimation. The first scheme is proposed to parameterize the SCM via a sum of a series of matrices in the time domain. The second scheme measures the SCM on each subcarrier as a low-rank model while the model order can be chosen through the penalized-likelihood approach. Simulation results are provided to demonstrate the effectiveness of the proposed method.

关键词： channel estimation spatial covariance matrix（ SCM ） estimation interference rejection interferencerejection combining （IRC） receiver

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Downlink BER performance analysis of distributed antenna systems over shadowed Rayleigh fading channels

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Journal of Southeast University(English Edition) 2009年第2期25卷 167-170页

作者：陈华敏陈明东南大学移动通信国家重点实验室南京210096

Due to the complexity of the composite fading channel, a new simplified channel model is proposed to analyze the bit error ratio（BER） performance of the distributed antenna system （DAS）. First, instead of the gamma-log-normal distribution, the log-normal distribution is applied to describe the output signal to noise ratio（SNR） after maximal ratio combining （MRC） at the receiver. Then, assuming that the channel state information（CSI） is available to the transmitter, by employing the Gauss-Hermite integral, an approximate analytical expression of the BER is derived for the downlink of the DAS with antenna selective transmission and MRC. Finally, the results of a Monte Carlo simulation show that the analytical results match the simulation results. Therefore, it can be concluded that the proposed approximate channel model is effective and accurate, and the derived analytical expression can be used to evaluate the real system performance.

关键词： distributed antenna system bit error ratio shadowed Rayleigh fading log-normal gamma-log-normal

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一种基于高阶谱的平稳随机信号的高斯性检验算法

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数据采集与处理 2009年第5期24卷 563-566页

作者：吴泳澎东南大学移动通信国家重点实验室南京210096

为了提高短数据序列下对称分布和冲击型样本的高斯检验性能,提出了一种基于高阶谱的平稳随机信号的高斯性检验算法。采用高斯核函数进一步分析了高斯分布的三谱特性。在此基础上,以反映三谱波动性的方差为统计量建立了一个新的三谱检验... 详细信息

为了提高短数据序列下对称分布和冲击型样本的高斯检验性能,提出了一种基于高阶谱的平稳随机信号的高斯性检验算法。采用高斯核函数进一步分析了高斯分布的三谱特性。在此基础上,以反映三谱波动性的方差为统计量建立了一个新的三谱检验模型,将该三谱检验模型与双谱秩和检验模型相结合组成一个高阶谱检验模型。仿真表明,该模型在短数据序列下可以取得比传统模型更好的高斯性检验结果。

关键词：高斯性检验秩和检验高阶谱高斯核函数

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Closed BER expression of multi-user DS UWB systemsin indoor fading channel

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Journal of Southeast University(English Edition) 2006年第1期22卷 16-20页

作者：樊祥宁黄勇富毕光国东南大学移动通信国家重点实验室南京210096

The bit error rate （BER） performance of multi-user direct spreading bi-phase shift keying （DSBPSK） direct impulse ultra wideband （UWB） systems is analyzed and simulated based on a statistical indoor multi-path fading channel model. The BER of the system is theoretically derived and given in closed form, which is expressed in terms of channel parameters and system parameters such as pulse width parameter, pulse repeat period, user number and pulse waveform. With this BER expression, the effect of these parameters on the system performance can be evaluated in a uniform way. Simulation results well match the theory numerical results, and prove that the multi-access interference （MAI） of DS-BPSK UWB is a normal distribution.

关键词： ultra wideband （UWB） direct spreading （DS） bi-phase shift keying （BPSK） multi-user fading channel performance analysis

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Iterative receivers for SFBC-OFDM systems with adaptive training scheme

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Journal of Southeast University(English Edition) 2005年第2期21卷 127-131页

作者：井雅徐晓东陈明程时昕东南大学移动通信国家重点实验室南京210096

This paper considers the design of iterative receivers for space-frequencyblock-coded orthogonal frequency division multiplexing (SFBC-OFDM) systems in unknown wirelessdispersive fading channels. An iterative joint channel estimation and symbol detection algorithm isderived. In the algorithm, the channel estimator performs alternately in two modes. During thetraining mode, the channel state information (CSI) is obtained by a discrete-Fourier-transform-basedchannel estimator and the noise variance and covariance matrix of the channel response is estimatedby the proposed method. In the data transmission mode, the CSI and transmitted data is obtainediteratively. In order to suppress the error propagation caused by a random error in identifyingsymbols, a simple error propagation detection criterion is proposed and an adaptive training schemeis applied to suppress the error propagation. Both theoretical analysis and simulation results showthat this algorithm gives better bit-error-rate performance and saves the overhead of OFDM systems.

关键词： space-frequency block-coded orthogonal frequency division multiplexing(SFBC-OFDM) iterative receiver channel estimation adaptive training scheme

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