多输入多输出系统中多用户的最大可达速率研究

理论地分析计算了多输入多输出（MIMO）系统中多用户的最大可达传输速率,其中分别包括上行和下行速率。在MIMO系统中分析比较了时分多址（TDMA）的多用户实际可达的传输速率。     

多用户MIMO系统中一种基于一位反馈信息的调度算法

针对多用户MIMO(Multiple-Input Multiple-Output)无线通信系统潜在的多用户分集增益,该文提出了一种基于一位反馈信息的多用户调度算法.理论分析表明,设置合理的门限可以从统计意义上最大化系统平均频谱效率.同时,该文从理论上对最优门限的选择进行了分析.仿真结果表明所提算法可有效利用多用户分集来提高系统的频谱性能.     

Linear-Dispersion Division Multiple-Access for MIMO systems

Comprehensive study on novel Linear-Dispersion Division Multiple-Access（LDDMA） for multi-user uplink Multiple-Input Multiple-Output（MIMO）systems is proposed.In the new multiplexing scheme,each user’s information symbol is dispersed by a User-Specific Matrix（USM）both in space and time domain and linearly combined at base-station side.And a simple random search algorithm,based on capacity maximization criteria,is developed to generate a bank of USMs.Simulation results are presented to demonstrate the advantages of LDDMA.When the Bit Error Rate（BER） reaches 10^–3,the performance gains are 3dB and 5dB,compared with Time-Division Linear Dispersion Codes（TD-LDC）and BLAST,respectively.     

A pilot-assisted non-Cyclic Prefixed MIMO-SCFDE system

A non-Cyclic Prefixed Multiple-Input Multiple-Output Single-Carrier Frequency-Domain Equalization (non-CP MIMO-SCFDE) system based on a recursive algorithm of Joint Channel Es- timation and Data Detection (recursive-JCEDD) is proposed in this paper. Unlike the traditional CP MIMO-SCFDE system, the transmitted block of the proposed system is designed in the way that block-type pilot sequences and Single-Carrier (SC) information sequences have been arranged alter- nately without any cyclic prefix before each ...     

A novel indoor geo-location method using MIMO array

In a Multiple-Input Multiple-Output （MIMO） Orthogonal Frequency Division Multiplexing （OFDM） based Wireless Local Area Network （WLAN） system, both Access Points （APs） and Mobile Terminals （MTs） are configured with multiple antennas, to make novel indoor geo-location method possible. In this paper, we presented a novel Least Square Support Vector Machine （LS-SVM） based data fusion algorithm to fuse signal strength measurements for indoor geo-location using only a single AP with MIMO arrays. We evaluate our proposed algorithms under indoor environments by MATLAB simulations. Simulation results show that our MIMO-based algorithm is superior to conventional least square algorithm.     

TDD MISO系统中波束成形的性能分析

文中首先指出在时分双工多输入单输出系统中,发送机和接收机的信道状态信息存在时延,而该时延会影响波束成形的性能增益。随后,通过推导接收机误比特率的闭合表达式,说明时延会损害接收机的性能。最后,用数值仿真验证了所做的性能分析的正确性。     

FSO MIMO系统中分层空时码检测算法

多输入多输出(MIMO)系统可以有效提高频谱效率和系统容量。基于MIMO系统重点研究了无线光通信垂直分层空时系统(V-BLAST)检测算法。首先分析了最大似然、线性迫零、最小均方误差以及排序干扰抵消等典型的传统检测算法,基于OOK调制和4PPM调制对采用不同检测算法的系统差错性能进行了仿真对比,最后对Turbo码与BLAST技术相结合构成的新系统采用了软输入软输出(SISO)迭代检测译码方案。仿真结果表明,分层空时检测算法中性能最优的是ML,其次是SISO-MAP,ZF算法性能最差;Turbo-BLAST系统可以有效提高无线光通信系统的抗干扰性能。     

Estimation of carrier frequency offsets for MIMO systems with distributed transmit antennas

The problem of estimating the carrier frequency offsets in Multiple-Input Multiple-Output (MIMO) systems with distributed transmit antennas is addressed. It is supposed that the transmit antennas are distributed while the receive antennas are still centralized, and the general case where both the time delays and the frequency offsets are possibly different for each transmit antenna is considered. The channel is supposed to be frequency flat, and the macroscopic fading is also taken into consideration. A carrier frequency offset estimator based on Maximum Likelihood (ML) is proposed, which can separately estimate the frequency offset for each transmit antenna and exploit the spatial diversity. The Cramer-Rao Bound (CRB) for synchronous MIMO (i.e., the time delays for each transmit antenna are all equal) is also derived. Simulation results are given to illustrate the per- formance of the estimator and compare it with the CRB. It is shown that the estimator can provide satisfactory frequency offset estimates and its performance is close to the CRB for the Signal-to-Noise Ratio (SNR) below 20dB.