共查询到20条相似文献,搜索用时 281 毫秒
1.
2.
水声通信网络的快速发展对多用户水声物理层通信技术提出了迫切的需求。本文主要针对水声多用户下行通信链路中存在严重码间干扰和多址干扰的问题,提出了一种交织多址(IDMA)水声多用户下行通信链路迭代接收算法,能够根据译码器输出的软信息对估计的信道进行迭代更新,同时根据信道估计结果重建各用户对当前用户的多址干扰(MAI),并使用干扰抵消器予以抵消,通过在均衡器、译码器和干扰抵消器之间的迭代逐次提高当前用户信息的输出信噪比,最终实现正确解调。其中,信道估计算法采用LMMSE初始化的分簇OMP稀疏信道估计算法,多普勒估计采用时频二维搜索结合自相关相位估计的方法,计算机仿真结果表明该接收机具有与已知信道时接近或相当的性能。进行了多用户水声通信海上试验,在4.5km、6km和7km三个距离实现了对2个用户、3个用户和4个用户的同时通信,每个用户的通信净速率约为500bps,证明了本文所提出的方法能够有效应用在多用户水声通信中,为水声通信网络的发展提供了一种重要的物理层通信技术手段。 相似文献
3.
协作多点传输(CoMP)是3GPP长期演进(LTE)的一个重要技术点,并将在上行采用多用户MIMO技术。分析了上行构成多用户MIMO的用户配对选择方法,并提出了一种在物理层进行用户传输速率公平性的调度方法,使系统在单个用户性能与整个系统的频率效率间取得较好的折衷。用系统仿真的方法对系统性能进行了仿真,证明了所提出算法的有效性。 相似文献
4.
5.
基于SLNR准则的MU-MIMO下行链路的预编码与用户调度 总被引:2,自引:0,他引:2
在多用户MIMO(MU-MIMO)系统的下行链路中,为了降低用户端的处理复杂度,发射端预编码的设计对多用户MIMO系统的性能非常重要,基于信漏噪比(SLNR)准则的预编码技术由于同时考虑了共信道干扰(CCI)和噪声,提高了系统的性能,但基站同时服务的用户有限,基于信漏噪比最大的用户调度能够合理地选择用户,提高了多用户分级增益,使系统获得更高的系统容量和系统性能。仿真结果表明,基于SLNR准则的多用户预编码在系统容量和误码率方面要优于单一考虑CCI的迫零预编码(ZF)和单一考虑噪声的最大化每个用户接收到信号的信噪比预编码(MRT)。在采用SLNR预编码的条件下,信漏噪比最大的用户调度系统性比轮询调度和最大信道增益调度好,并且随着待选用户数的增多,不会给系统的调度策略带来很大的影响。 相似文献
6.
7.
8.
9.
10.
预编码技术能够有效的抑制MIMO信道中的多用户干扰,能显著提高系统容量,同时也能大大简化接收机的算法。主要对MIMO—OFDM系统的非线性预编码技术进行了深入研究,通过搭建出的MIM0-OFDM仿真平台对DPC(DirtyPaperCoding,脏纸编码)和THP(TomlinsonHarashimaPre—coding,模代数TH编码)两种非线性预编码算法进行了性能仿真,比较了这两种算法的BER(误码率),同时也比较了它们与线性zv(ZeroForcing,迫零)预编码算法的BER差异,并指出了不同算法的适用性。 相似文献
11.
Zi-Wei Zheng 《Wireless Personal Communications》2010,53(1):67-79
In this paper, we consider the receiver design problem for the uplink multiuser code division multiple access (CDMA) communication
system based on the neural network technique. The uplink multiuser CDMA communication system model is described in the form
of space–time domain through antenna array and multipath fading expression. Novel suitable neural network technique is proposed
as an effective signal processing method for the receiver of such an uplink multiuser CDMA system. By the appropriate choice
of the channel state information for the neural network parameters, the neural network can collectively resolve the effects
of both the inter-symbol interference due to the multipath fading channel and the multiple access interference in the receiver
of the uplink multiuser CDMA communication system. The dynamics of the proposed neural network receiver for the uplink multiuser
CDMA communication system is also studied. 相似文献
12.
平衰落信道中的空间特征估计算法及其在空分多址中的应用 总被引:2,自引:0,他引:2
本语文提出了一种基于累量的多用户空间特征估计算法,并将该算法用于智能天线中空分多址的实现,该算法构造螺量域空间特征矩阵,通过对空间特征矩阵的特征分散得到各用户信号嚓间特征估计,基于空间特征的估计,设计了用于上行多波束成形的空间滤波器组,实现了上行多用户信号的分离,仿真实验表明,空间滤波器的响应可用于相干源的波达方向估计,为实现频分双工系统的下行选择性发送提供了依据。 相似文献
13.
传统的多用户处理是在上行进行的,本文提出了应用于TDD-CDMA系统中下行方向的一种多用户处理方案.在TDD-CDMA系统中,可以利用上行信道参数对下行信道参数做出估计.本文提出了一种实时利用信道参数来降低CDMA中的多用户干扰的方法.在该方案中,其多用户处理的基本思路是通过优化系统的多用户扩频码字和解扩码字来降低多用户干扰.为了达到最大的信干比,本文提出了系统扩频码选择的优化准则,它能够充分利用信道的特性.本文根据一定的迭代算法给出优化问题的解.数值分析结果表明,采用上述方案的CDMA系统相对于采用Gold码的系统能够极大地降低多用户干扰,提高信干比. 相似文献
14.
Distributed multiuser detection for the TDMA cellular uplink 总被引:1,自引:0,他引:1
A method for performing multiuser detection using observations from multiple base stations is proposed. Log-likelihood ratio estimates of the data are calculated at each base station and combined to form the final decision statistic. The proposed architecture is applied to the time division multiple access (TDMA) cellular uplink, and it is shown that heavily overloaded systems can perform remarkably well 相似文献
15.
16.
Yonghoon Choi 《ETRI Journal》2014,36(6):953-959
This paper studies the uplink resource allocation for multiple radio access (MRA) in reconfigurable radio systems, where multiple‐input and multiple‐output (MIMO) multicarrier‐code division multiple access (MC‐CDMA) and MIMO orthogonal frequency‐division multiple access (OFDMA) networks coexist. By assuming multi‐radio user equipment with network‐guided operation, the optimal resource allocation for MRA is analyzed as a cross‐layer optimization framework with and without fairness consideration to maximize the uplink sum‐rate capacity. Numerical results reveal that parallel MRA, which uses MC‐CDMA and OFDMA networks concurrently, outperforms the performance of each MC‐CDMA and OFDMA network by exploiting the multiuser selection diversity. 相似文献
17.
空时分组码MC-CDMA系统多用户检测 总被引:2,自引:2,他引:2
本文研究了在频率选择性瑞利衰落信道中工作于时分双工(TDD)模式的多载波码分多址(MC-CDMA)系统上行链路,在用户终端处使用两个发射天线,采用基于空时分组码的发射分集。考虑对应于子载波的衰落系数是信道冲激响应的离散傅里叶变换,给出了基于空时分组码的MC-CDMA系统上行链路信号模型。采用适用于同步CDMA系统的低代价Steiner估计器来进行基于空时分组码的MC-CDMA系统的信道估计,每个用户终端的两个发射天线各分配一个midamble。研究了基于空时分组码的MC-CDMA系统的解相关多用户检测、最小均方误差(MMSE)多用户检测,进行联合的多用户检测和空时码解码。仿真结果验证了上述模型及算法的有效性。 相似文献
18.
LIU Jun-shi TANG Bi-hua WANG Ya-chen LIU Yuan-an.School of Telecommunications Engineering Beijing University of Posts Telecommunications Beijing P.R. China .School of Electronic Engineering Beijing University of Posts Telecommunications Beijing P. R. China 《中国邮电高校学报(英文版)》2006,13(2):90-94
1Introduction Recently,MultipleInputMultipleOutput(MIMO)wirelesstechnologieshavecapturedalotofresearchin terest,giventhatthecapacityincreaseturnsouttobe achievable[1-2].OrthogonalFrequencyDivisionMulti plexing(OFDM)techniquehastheremarkablecharac teristic… 相似文献
19.
Performance Analysis of Multiuser Detectors for Uplink Quasi-synchronous MC-CDMA Systems 总被引:1,自引:1,他引:1
Felip Riera-Palou Guillem Femenias Jaume Ramis 《Wireless Personal Communications》2007,43(4):1511-1521
This paper analyses and compares the average bit error rate (BER) of different multiuser detectors (MUD) in the uplink of
a multicarrier code- division multiple access (MC-CDMA) system. In particular, maximum likelihood, zero-forcing, minimum mean-square
error and interference cancellation-based multiuser detectors have been analysed for the special case of uncorrelated subcarriers.
The derived BER expressions are based upon previous results on diversity combining and also on recent findings on multiple
input multiple output (MIMO) architectures. The subcarrier correlation is considered in the context of physical parameters
currently under discussion for future wireless systems to give an indication up to what extent the assumption of uncorrelated
subcarrier fading is plausible. 相似文献
20.
Safdar Nawaz Khan Marwat Thushara Weerawardane Yasir Zaki Carmelita Goerg Andreas Timm-Giel 《Wireless Personal Communications》2014,79(3):2305-2322
Long term evolution (LTE) uses orthogonal frequency division multiple access (OFDMA) and single carrier frequency division multiple access (SC-FDMA) as the downlink and uplink transmission schemes respectively. The Quality of Service (QoS) provision to users is one of the key objectives of the wireless network operators. This paper analyses an uplink LTE radio scheduler, called bandwidth and QoS aware (BQA) scheduler and evaluates its QoS performance. The BQA uplink scheduler is designed to provide efficient and fair allocation of the radio resources to users according to: the QoS of various traffic classes and the instantaneous channel conditions. The scheduler functionality is divided into time domain packet scheduling (TDPS) and frequency domain packet scheduling (FDPS). In this paper, an innovative feature, that is user QoS provisioning with dynamic QoS weights, is employed for the BQA scheduler along with multi-bearer users support. The QoS performance of the BQA scheduler is analyzed in several simulation scenarios using heterogeneous traffic environment. The results show that the BQA scheduler guarantees provision of QoS to users. 相似文献