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Beamforming and DOA estimation for multiuser in multipath circumstance

An Yi,Lu Xin,Gao Benqing,

电子与信息学报 , 2002,
Abstract: In this paper beamforming and DOA estimation for multiuser are discussed in multipath circumstance. Decorrelating detector is adopted to detect multiuser. CSS(Cyclic Spatial Smoothing) algorithm is presented. The algorithm with spatial smoothing can keep array weight dimension unchanged. Its theoretical foundation is that cyclic propagation of the sampling signal covariance inverse matrix is equivalent to averaging of the covariance matrix. The estimated spatial signature is adopted to construct the covariance matrix for high resolution DOA estimation. The simulation results show that CSS has better performance for multiuser beamforming.
A Capacity Improvement Method for CDMA based Mesh Networks in SUI Multipath Fading Channels  [PDF]
Muhammad Zeeshan,Shoab A Khan,Muhammad Yasir Malik
Mathematics , 2011,
Abstract: Code Division Multiple Access (CDMA) is the most promising candidate for wideband data access. This is due to the advantage of soft limit on the number of active mobile devices. Many wireless mesh systems impose an upper bound on the BER performance which restricts the increase in number of mobile users. Capacity is further reduced in Multipath Fading Environment (MFE). This paper presents an effective method of improving the capacity of a CDMA based mesh network by managing the transmitted powers of the mobile devices and using MMSE based Multiuser Detection (MUD). The proposed scheme improves the capacity two times as compared to the conventional CDMA based mesh network. Simulation results have been presented to demonstrate the effectiveness of the proposed scheme.
Blind adaptive multiuser detection in multipath fading channel based on affine projection algorithm

LI Hui,YU Hong-mei,DUAN Hang-yu,

计算机应用研究 , 2008,
Abstract: The computational complexity of the blind adaptive multiuser detection algorithm with multipath fading channel was usually high.By combining RAKE receiver and blind multiuser detection based on the affine projection algorithm(APA),presented an adaptive receiver which could be used in multipath fading channel.This new algorithm could balance the contradiction between the convergence speed and computational burden.The simulation results show that the proposed receiver has similar good convergence and tracking properties as the RLS-based scheme with much reduced computational cost.

Jiang Xiaobing,Xue Qiang,Feng Yumin,

电子与信息学报 , 2003,
Abstract: In this paper, a new CLSCMA-based blind adaptive multiuser detection which can be used in multipath channel is proposed. Analysis and simulations show that the approach converges fast and has a good performance, so it is a good adaptive multiuser detection.
多个分户验收组织的人员配置  [PDF]
系统工程理论与实践 , 2010,
Abstract: ?提出了基于层次分析(ahp)和数据包络分析(dea)的多个分户验收组织人员配置的方法.以验收组织的各种专业人员数与其权重系数的乘积,验收项目的验收合格率、对应的层次分析法的组合权系数及验收组织负责验收的建筑面积的乘积(顾客满意度)分别作为dea模型的输入项和输出项,通过模型求解和灵敏度分析,得出了下一阶段分户验收组织的人员配置数.弥补了传统的组织人员配置与调整方法仅考虑组织的工作效率,而忽略了组织的工作效果的不足.
An improved blind space-time multiuser detection in multipath CDMA channels

Zheng Jianzhong,Jiao Licheng,

电子与信息学报 , 2002,
Abstract: An improved LMS blind space-time multiuser detection method based on the Rosen's gradient projection to realize in multipath CDMA channels is presented. Comparison with the original method, the proposed method has advantages in complexity and requirement of the system. However, the results of simulation comparison illustrate that the detection performance of the proposed multiuser space-time processing method do not deteriorate, and prove that this method has advantage over the original method in the competition of market.
On the Non-Coherent Wideband Multipath Fading Relay Channel  [PDF]
Nadia Fawaz,Muriel Medard
Mathematics , 2010,
Abstract: We investigate the multipath fading relay channel in the limit of a large bandwidth, and in the non-coherent setting, where the channel state is unknown to all terminals, including the relay and the destination. We propose a hypergraph model of the wideband multipath fading relay channel, and show that its min-cut is achieved by a non-coherent peaky frequency binning scheme. The so-obtained lower bound on the capacity of the wideband multipath fading relay channel turns out to coincide with the block-Markov lower bound on the capacity of the wideband frequency-division Gaussian (FD-AWGN) relay channel. In certain cases, this achievable rate also meets the cut-set upper-bound, and thus reaches the capacity of the non-coherent wideband multipath fading relay channel.
Scheme of key generation based on multipath relative-delay

ZHOU Bai-peng,HUANG Kai-zhi,JIN Liang,LI Yin-hai,

计算机应用研究 , 2011,
Abstract: To overcome the drawbacks of the current key distribution mechanism,explored an alternative method for generating secret keys by exploiting the identical of channel characteristics between uplink and downlink in TDD system. As the multipath delay satisfied the channel reciprocity in wideband system, it designed a new key generation scheme. In which the receiver extracted the multipath relative-delay and generated the keys by calculating the difference between the relative-delay and the mean-delay. The simulation results utilizing the UWB channel demonstrate that the scheme has the robustness and the key agreement even equal to 95% when the SNR is 15dB.
UWB Multipath Channel Modulation Mode Analysis of the Bit Error Rate

杨英杰, 王晓峰, 曲朝阳, 张文龙
Yang Yingjie
,Wang Xiaofeng,Qu Zhaoyang,Zhang Wenlong

- , 2015, DOI: 10.6054/j.jscnun.2015.03.015
Abstract: 为了研究Ultra-Wideband(UWB)系统中可分辨多径分量和不可分辨多径分量携带信号的误码率问题,利用Radio Activated Key Entry(RAKE)接收机的分集技术,在信号发射端分别采用 Binary Phase Shift Keying (BPSK)和Pulse Position Modulation(PPM)调制方式,从这2种调制方式的解析式入手,推导出BPSK与PPM在可分辨和不可分辨多径分量下误码率表达式,并针对在相同叉指数和信噪比下,分别对这2种多径分量信号在不同调制方式下的误码率进行仿真分析.仿真结果表明,在相同调制方式下,可分辨多径的抗误码率性能要优于不可分辨多径的情况.而且,采用BPSK调制无论是可分辨多径还是不可分辨多径,在抗误码率性能上,均优于PPM调制方式.
: In order to study the problem that Ultra-Wideband (UWB)system can distinguish the multipath components and indiscernibility more carrying signals, Rake receiver diversity technology is used. In the signal transmitter, Binary Phase Shift Keying (BPSK) and Pulse Position Modulation (PPM) modulation method are used respectively. From the analytic expression of these two kinds of modulation mode,elicit BPSK and PPM in the resolvable multipath and indiscernibility multipath error rate expression are induced. For the same fork index and signal-to-noise ratio,two kinds of multipath component signals under different modulation mode of simulation analysis are conducted. The simulation results show that,under the same modulation mode,distinguish the multipath error rate resistance is superior to the indiscernibility multipath situation. No matter in distinguish multipath or indiscernibility multipath, BPSK modulation is superior to PPM modulation method on resistance error rate
Performance Analysis of Iterative Channel Estimation and Multiuser Detection in Multipath DS-CDMA Channels  [PDF]
Husheng Li,Sharon M. Betz,H. Vincent Poor
Mathematics , 2006, DOI: 10.1109/TSP.2007.893229
Abstract: This paper examines the performance of decision feedback based iterative channel estimation and multiuser detection in channel coded aperiodic DS-CDMA systems operating over multipath fading channels. First, explicit expressions describing the performance of channel estimation and parallel interference cancellation based multiuser detection are developed. These results are then combined to characterize the evolution of the performance of a system that iterates among channel estimation, multiuser detection and channel decoding. Sufficient conditions for convergence of this system to a unique fixed point are developed.
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