共查询到19条相似文献,搜索用时 875 毫秒
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利用高斯Q函数的高阶次幂在最大比合并(MRC)分集接收瑞利衰落信道上统计平均的结果,推导了Nakagami 衰落信道上采用组合发射选择合并(SC)/接收 MRC 天线分集的相干检测差分编码四相相移键控(DE-QPSK)的平均误符号率(ASER)精确表达式。利用高斯Q函数的近似表达式和矩生成函数(MGF)方法,推导了Nakagami衰落信道上采用组合SC/MRC天线分集的相干检测DE-QPSK 的ASER近似表达式。通过数值计算和仿真,验证了DE-QPSK的ASER精确表达式的正确性以及近似表达式的准确性。利用精确表达式和近似表达式可研究收发天线数目和衰落参数对DE-QPSK的ASER性能的影响,为实际SC/MRC天线分集方案的设计提供了理论指导。 相似文献
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相关衰落信道上MIMO系统中组合SC/MRC的性能分析 总被引:1,自引:0,他引:1
研究相关瑞利衰落信道上MIMO系统中组合发射机选择合并(SC)/接收机最大比合并(MRC)的天线分集系统性能.使用矩生成函数方法,推导相关瑞利衰落信道上采用组合SC/MRC天线分集争相干检测的M进制相移键控(MPSK),M进制正交幅度调制(MQAM),M进制脉冲幅度调制(MPAM)等几种M进制数字调制方式的误符号率精确表达式.数值计算结果阐明相关性和天线阵结构对采用组合SC/MRC天线分集的几种M进制数字调制方式的平均误符号率性能的影响. 相似文献
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Nakagami衰落信道上组合SC/MRC的性能分析 总被引:1,自引:0,他引:1
研究Nakagami衰落信道上组合发射机选择合并(SC)/接收机最大比合并(MRC)天线分集系统的性能.使用矩生成函数方法,推导采用组合SC/MRC天线分集和相干检测的MPSK(M进制相移键控)、MQAM(M进制正交幅度调制)、MPAM(M进制脉冲幅度调制)、BFSK(二进制频移键控)、最小相关BFSK(BFSKmin)、差分编码BPSK(DE-BPSK)和预编码MSK(最小频移键控)等几种M进制数字调制方式在Nakagami衰落信道上的误符号率性能,获得了M进制数字调制系统误符号率性能的精确数学表达式.数值计算结果阐明了发射天线和接收天线数目以及衰落参数对数字调制系统误符号率性能的影响. 相似文献
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通过选择性最大比合并(SC/MRC)算法,在并行干扰抵消(PIC)技术的基础上,对V-BLAST系统各接收天线的干扰抵消结果按照SC/MRC合并,实现了分集接收.该算法最多可以实现与接收天线数等同的分集增益,而通过选择信道条件较好的几个接收天线进行合并,可以在性能与复杂度之间取得折衷.MRC合并只需与选择合并的天线数线... 相似文献
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采用两条支路分集接收的相关瑞利衰落信道容量 总被引:5,自引:0,他引:5
本文研究采用两条支路最大比合并(MRC)或选择合并(SC)分集接收的相关瑞利衰落信道理论容量推导恒定发射功率自适应M进制正交幅度调制(M-QAM)的频谱效率,并将它们与独立同分布瑞利信道理论容量进行比较,其结果对收发信机之间无视距分量路径、接收机上分集天线之间的距离小于半个波长的无线通信系统设计具有指导作用. 相似文献
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根据弱湍流信道中对数正态分布模型,建立了紫外光非直视分集接收系统。采用开关键控(OOK)调制,在不同闪烁指数和接收天线数下,分别对比分析了最大比合并(MRC)、等增益合并(EGC)和选择性合并(SC)的误码性能。仿真结果表明,相比于无分集情况,采用三种合并方式的误码率性能有明显提升。在接收天线数相同的情况下,三种合并方式中,MRC的性能最优,其次是EGC,SC的性能最差。对比分析了不同接收天线数时的误码率性能,随着接收天线数的增加,三种合并方式的误码性能得到了较大改善。在弱湍流信道中,采用分集接收技术能够减轻衰落的影响,提高分集增益。 相似文献
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MIMO衰落信道上MR-MQAM性能分析 总被引:2,自引:2,他引:0
使用矩生成函数方法分别推导了Nakagami衰落信道上多分辨率M进制正交幅度调制(MR-MQAM)的平均误比特率(BER)闭合表达式,发送和接收分别采用选择合并/最大比合并(SC/MRC)和正交空时分组编码(OSTBC).数值计算结果表明在相同的天线设置条件下,SC/MRC方案的平均误比特率性能要优于OSTBC. 相似文献
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Thoen S. Van der Perre L. Gyselinckx B. Engels M. 《Communications, IEEE Transactions on》2001,49(1):5-8
The average bit-error rate of transmit antenna selection combined with receive maximum-ratio combining is computed as a function of the transmit antenna update rate when using binary phase-shift keying in flat Rayleigh fading channels. This scheme achieves an order of diversity equal to the product of the number of transmit and receive antennas. Therefore, it can gain significant diversity benefits over traditional receive diversity schemes by distributing the antennas over the transmit and receive side 相似文献
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日益增长的无线业务需求要求提高衰落信道上无线通信的频谱利用率。本文利用Q2(x)的另一种数学表达式和矩生成函数推导了Nakagami-m衰落信道上多输入多输出(MI-MO)WCDMA系统采用M进制正交幅度调制(MQAM)的平均误符号率(ASER)表达式,分析框架可以推广到开环和闭环系统发射和接收天线为任意数目的应用场合,研究了存在多址干扰下MIMOWCDMA系统的平均误符号率性能,数值计算结果表明组合发送分集和接收分集可以显著改善系统的性能。 相似文献
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A new diversity combining algorithm is presented in this paper with high performance in the STBC single carrier (SC) block
transmission MISO system with two transmit antennas and one receive antenna. The decision on the transmitted signal is made
by STBC-based SC frequency domain equalizer (STBC-SC-FDE), and then the line of sight (LOS) component under Rician fading
channels or the component with highest power under Rayleigh fading channels in the received signal is obtained by cancelling
the multipath signals reconstructed by the initial detecting solution and the channel impulse response (CIR) from the received
signal. Then, the LOS or the strongest component is combined using STBC-like combining scheme. The new algorithm can achieve
the performance advantages dramatically over STBC-SC-FDE which is verified by computer simulations carried out in the SUI-4
and TU wireless communication link. 相似文献
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Space-time coding techniques significantly improve transmission efficiency in radio channels by using multiple transmit and/or receive antennas and coordination of the signaling over these antennas. Bit-interleaved coded modulation gives good diversity gains with higher order modulation schemes using well-known binary convolutional codes on a single transmit and receive antenna link. By using orthogonal frequency division multiplexing (OFDM), wideband transmission can be achieved over frequency-selective fading radio channels without adaptive equalizers. In this correspondence, we combine these three ideas into a family of flexible space-time coding methods. The pairwise error probability is analyzed based on the correlated fading assumption. Near-optimum iterative decoders are evaluated by means of simulations for slowly varying wireless channels. Theoretical evaluation of the achievable degree of diversity is also presented. Significant performance gains over the wireless local area network (LAN) 802.11a standard system are reported. 相似文献
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基于Alamouti提出的BPSK调制下空时分组码在Rayleigh衰落信道中的简单分集方案。推导出多发射和多接收天线系统中正交空时分组码在Nakagami衰落信道的BPSK调制下的比特差错率的最小距离球界,并推广到在高阶调制下衰落信道中系统符号差错率的性能。仿真分析和比较了空时分组码的多天线系统中发射和接收天线分集增益,以及信道相关参数的变化对系统误比特性能的影响。 相似文献
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Ling Li Yu-Dong Yao Hongbin Li 《Vehicular Technology, IEEE Transactions on》2003,52(5):1217-1231
Rapid growth and increasing demands for near-ubiquitous high-quality high-data-rate services present the most challenges for wireless system design. As an effective method to provide such services, space-time (ST) coding is gaining more and more attention. The paper extends ST coding, originally designed for known frequency-nonselective fading channels, to unknown frequency-selective channels. An ST transmit diversity wireless time-division multiple-access system, that is equipped with multiple antennas at both transmit and receive sides, is considered. In this system, a novel scheme is presented to suppress intersymbol interference and to demodulate coherently the information symbols with estimated channel state information. The proposed algorithm is powerful and computationally efficient. In addition to the discussion of system identifiability, both theoretical analysis and numerical simulation are presented to illustrate the performance of the proposed estimator and receiver in multipath fading channels. 相似文献
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Multiuser Interference Cancellation and Detection for Users with More Than Two Transmit Antennas 总被引:1,自引:0,他引:1
We consider J transmitter units each equipped with N transmit antennas over wireless Rayleigh fading channels. Previously in [1], it was proved that when each transmitter unit has TV transmit antennas, using (J - 1)N + r receive antennas for any r ges 1, the receiver can completely separate the signals of J users. The provided diversity to each user was shown to be Nr if the units employ space-time trellis codes even if the units transmit asynchronously. Here, we consider the case when all units are synchronized and employ quasi-orthogonal space-time block codes (N > 2). It is proved that in this case a receiver with J + r - 1 antennas with r ges 1 can separate the transmitted signals of all units and provide each unit with a diversity order of Nr. Based on our interference cancellation technique, we then offer an array processing scheme which provides trade-off between diversity and spatial multiplexing. It is shown via simulations that this array processing scheme performs better than well-known modulation schemes, e.g. space-time block codes and BLAST, for a moderate number of receive antennas. 相似文献
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The potential promised by multiple transmit antennas has raised considerable interest in space-time coding for wireless communications. In this paper, we propose a systematic approach for designing space-time trellis codes over flat fading channels with full antenna diversity and good coding advantage. It is suitable for an arbitrary number of transmit antennas with arbitrary signal constellations. The key to this approach is to separate the traditional space-time trellis code design into two parts. It first encodes the information symbols using a one-dimensional (M,1) nonbinary block code, with M being the number of transmit antennas, and then transmits the coded symbols diagonally across the space-time grid. We show that regardless of channel time-selectivity, this new class of space-time codes always achieves a transmit diversity of order M with a minimum number of trellis states and a coding advantage equal to the minimum product distance of the employed block code. Traditional delay diversity codes can be viewed as a special case of this coding scheme in which the repetition block code is employed. To maximize the coding advantage, we introduce an optimal construction of the nonbinary block code for a given modulation scheme. In particular, an efficient suboptimal solution for multilevel phase-shift-keying (PSK) modulation is proposed. Some code examples with 2-6 bits/s/Hz and two to six transmit antennas are provided, and they demonstrate excellent performance via computer simulations. Although it is proposed for flat fading channels, this coding scheme can be easily extended to frequency-selective fading channels. 相似文献