基于二型模糊集的多重多维多输出模糊推理模型及Mamdani算法

模糊推理是模糊控制技术的数学核心,二型模糊集的模糊推理是研究二型模糊逻辑系统的基础。类似一型模糊集模糊推理的Mamdani算法,研究并给出了二型模糊集的多重多维多输出模糊推理模型及相应的Mamdani算法。     

支持广义MIMO技术的软分数频率复用方法

为了提高小区边缘用户(CEU)性能,提出了一种新型软分数频率复用（SFFR）方法。与以往频率复用方法不同的是,区域和频率的规划使多个小区联合多个CEU形成广义多输入多输出(MIMO)系统,在小区边缘可支持共信道空间分集和空间复用。另一方面,利用SFFR思想的频率规划通过干扰协同提高了频谱效率和CEU信干比。CEU信干比提高后,与采用空间分集相比采用空间复用将更有利于提高CEU性能;因此,为了更大程度上优化系统吞吐量,在小区边缘,对下行多用户进行广义MIMO的空间复用;而小区中心用户仍然由单个小区为其提供服务。仿真结果表明,这种支持广义MIMO技术的新型SFFR方法显著地提高了CEU性能。     

两类多用户MIMO线性预编码的功率分配*

将多用户MIMO线性预编码分为干扰消除和干扰抑制两类,针对干扰消除中的块对角化（block diagonalization,BD）迫零算法,讨论了经典注水功率分配,提出一种信噪比控制功率分配方案。该方案可使系统各子流接收信噪比相同,各个用户的误码性能一致,也可控制用户之间的任意信噪比比例;研究了干扰抑制类预编码的统一功率分配方案,提出一种针对存在干扰系统的适用于相关信道的迭代注水算法。该算法引入经典注水的思想,将干扰和噪声一并考虑。仿真结果表明,该算法在相关信道下使系统和容量获得了明显提高。     

井下视频监控系统容量问题分析

针对基于无线Mesh网络的井下视频监控系统采用多跳传输技术导致系统容量降低、信号带宽下降等问题,提出在无线Mesh网络中采用多输入多输出技术来提高系统容量,并对多输入多输出系统的容量进行了分析和仿真验证。Matlab仿真结果表明,多输入多输出技术可以在不增加带宽的情况下有效地提高系统容量,解决了井下视频多跳传输过程中带宽下降的问题,从而提高了井下视频实时传输质量。     

Optimal adaptive channel scheduling for scalable video broadcasting over MIMO wireless networks

Video broadcasting is an efficient way to deliver video content to multiple receivers. However, due to heterogeneous channel conditions in MIMO wireless networks, it is challenging for video broadcasting to map scalable video layers to proper MIMO transmit antennas to minimize the average overall video transmission distortion. In this paper, we investigate the channel scheduling problem for broadcasting scalable video content over MIMO wireless networks. An adaptive channel scheduling based unequal error protection (UEP) video broadcasting scheme is proposed. In the scheme, video layers are protected unequally by being mapped to appropriate antennas, and the average overall distortion of all receivers is minimized. We formulate this scheme into a non-linear combinatorial optimization problem. It is not practical to solve the problem by an exhaustive search method with heavy computational complexity. Instead, an efficient branch-and-bound based channel scheduling algorithm, named TBCS, is developed. TBCS finds the global optimal solution with much lower complexity. The complexity is further reduced by relaxing the termination condition of TBCS, which produces a (1 − ε)-optimal solution. Experimental results demonstrate both the effectiveness and efficiency of our proposed scheme and algorithm. As compared with some existing channel scheduling methods, TBCS improves the quality of video broadcasting across all receivers significantly.     

ℒ1 adaptive controller for a class of non-affine multi-input multi-output nonlinear systems

In this article, an extension of the ?₁ adaptive control design is introduced for a class of non-affine Multi-Input Multi-Output nonlinear systems with unknown dynamics and unmeasured states. The system dynamics is represented in the normal form with the bounded-input-bounded-output internal dynamics. At first, a stable virtual reference counterpart is constructed. Thereafter, a piece-wise continuous adaptive law is introduced to the actual system along with a low-pass filtered control signal that allows for achieving arbitrarily close tracking of the input and the output signals of the reference system. Rigorous mathematical proof is provided, and the theoretical results are verified with the simulation.     

一类新非线性控制方法:基于演算子理论的控制方法综述

以基于演算子理论的鲁棒右互质分解 (Operator-based robust right coprime factorization, RRCF) 为基础, 提出了一种较新的非线性鲁棒控制方法.本文将简述此方法的概念、 基本理论及其应用. 具体地说, 本文首先介绍此方法的起源与基本概念; 然后,讨论此方法在系统的鲁棒稳定性、 输出跟踪与故障检测方面的设计等问题;最后,介绍此方法的实际应用从而进一步证明其有效性.     

Determination of Optimum Antenna Number Ratio Based on Differential Evolution for MIMO Systems under Low SNR Conditions

In this paper, we derive a simple expression to determine the optimum antenna number ratio for multi-input multi-output systems under low signal- to-noise ratio (SNR) conditions. The parameters of the proposed expression are optimally determined by the differential evolution algorithm. The accuracy of the new expression is evaluated at different low SNRs. Numerical results show that the expression introduced in this paper significantly outperforms the high SNR approximation, and the results exhibit very good agreement with the optimum antenna number ratios that maximize the noise-limited asymptotic capacity expression.     

多输入多输出可见光通信的天线布局研究

通过改变LED及光电探测器(PD)的 空间分布,得到不同的天线布局,同时通过改 变LED间距dTX、发射端和接收端平面的高度差h等条件,得到了不同的信道传输矩阵H,仿 真分析了以上各种情况下的室内可见光通信系统(VLC)的性能。结果表明,影 响VLC性能的关键参数包含最小欧式距 离dmin和行列式Det(H)。根据系统的关键 参 数,将天线布局分为圆形布局和格点布局两类,圆形布局是指所有LED或PD均 匀地分布在一个 圆上,而格点布局是指所有LED或PD均分布在二维平面中的格点上。仿真结果表明,当dTX变化时,在采 用圆形布局的系统中,行列式Det(H)是影响误码率(BER)的关键因素 ;在采用格点布局的系统中,dmin和Det( H)均是影响系统误码率的关键因素,但在d TX的一定范围内dmin是决定系统性能的关键因素 。而当h发生变化时Det(H)是影响系统性能的 关键因素。     

基于共享最小二乘支持向量机模型的电站锅炉燃烧系统的优化

电站锅炉燃烧系统是一个复杂的多输入多输出系统,为了在同一个模型中实现高效率、低污染物排放的优化目标,对标准最小二乘支持向量机回归方法进行了扩展．借助某电厂1000MW超超临界锅炉的现场燃烧调整试验数据,建立了以锅炉热效率和NOx排放质量浓度为输出的共享最小二乘支持向量机（LSSVM）模型,采用一种改进的粒子群算法对共享模型中的锅炉运行工况进行了寻优．结果表明：在共享LSSVM模型中,锅炉热效率和NOx排放质量浓度的平均预测误差分别可达到0．028％和2．16％,搜索得到的高效率和低NOx排放的参数组合可为电站锅炉优化运行提供指导．