scholarly journals Effect of Polarization on the Correlation and Capacity of Indoor MIMO Channels

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Hsun-Chang Lo ◽  
Ding-Bing Lin ◽  
Teng-Chieh Yang ◽  
Hsueh-Jyh Li
Keyword(s):  
Fading Channels ◽  
Channel Capacity ◽  
Mimo Systems ◽  
Mimo System ◽  
Multiple Input Multiple Output ◽  
Mimo Channel ◽  
Analysis Method ◽  
Mimo Channels ◽  
Received Power ◽  
Value Decomposition

We describe a simple multiple-input/multiple-output (MIMO) channel measurement system for acquiring indoor MIMO channel responses. Four configurations of the polarization diversity antenna, referred to asVVV,YYH,YVYandVHH, were studied in terms of the capacity of indoor MIMO systems. Measurements were taken for a3×3MIMO system in the 2.4 GHz band. In addition, the channel capacity, singular-value decomposition, and correlation coefficient were used to explain the effects of various polarization schemes on MIMO fading channels. We also propose an analysis method for polarization channel capacity; this method includes the normalization of the received power and polarization effect for different polarization schemes. The validation of the model is based upon data collected in both light-of-sight (LOS) and non-light-of-sight (NLOS) environments. From the numerical simulation results, the proposed analysis method was close to measurements made in an indoor environment.

On the Capacity of MIMO Channels with Outdated Channel State Information

2011 ◽  
Vol 204-210 ◽  
pp. 2053-2056
Author(s):  
Ying Li ◽  
Yi Jun Zhu ◽  
Lan Ma ◽  
Yao Zhu
Keyword(s):  
Fading Channels ◽  
Channel State Information ◽  
Multiple Input Multiple Output ◽  
Ergodic Capacity ◽  
Mimo Channel ◽  
Wide Sense ◽  
Mimo Channels ◽  
Channel State ◽  
State Information ◽  
Input Multiple Output

A Multiple-input multiple-output (MIMO) time-varying flat fading channel is considered. The transmitter obtained the channel state information (CSI) relying on the reciprocity principle or by the feedback from the receiver. Thus, channel state information at the transmitter (CSIT) is outdated due to the delay between the estimation of the channel and the transmission of the data. In order to achieve the maximum channel capacity, the transmitter linearly precoded the signal before transmission based on the outdated CSIT. Under the assumptions of wide-sense stationary uncorrelated scattering Rayleigh fading channels and Jake’s model, the instantaneous mutual information and ergodic capacity is derived for MIMO channels with outdated CSIT. The information outage probability of MIMO channel with outdated CSIT is also presented.

scholarly journals Analysis between Various Random MIMO systems Model On the Basis of Channel Capacity

2016 ◽  
Author(s):  
Shree Krishna Acharya
Keyword(s):  
Wireless Communication ◽  
Outage Probability ◽  
Channel Capacity ◽  
Mimo Systems ◽  
Mimo System ◽  
System Model ◽  
Mimo Channel ◽  
Systems Model ◽  
Capacity Model ◽  
Mimo Channel Capacity

Finding a good MIMO system model also major issue in Wireless Communication system. It is facing with so many problem, one of the major problem is finding good system model in terms of capacity. In this paper, we analyze the channel capacity of various MIMO system model with some constant SNR level and outage probability. We establish a novel idea for MIMO system models as consider as 2N- MIMO system model with constant SNR and outage probability. The channel capacity ratio is presented here on the basis of 2N- MIMO channel capacity model. Analysis of various MIMO system model show that it is better to use NT×NR MIMO system model then two NT/2×NR/2 MIMO system model in terms of channel capacity but it is not good for higher value of NT×NR

An Analysis of Valid Nodes Distribution for Sphere Decoding in the MIMO Wireless Communication System

2021 ◽  
Vol 2021 (2) ◽  
pp. 47-54
Author(s):  
Nguyễn Minh Thường
Keyword(s):  
Mimo Systems ◽  
Mimo System ◽  
Multiple Input Multiple Output ◽  
Middle Layer ◽  
Search Space ◽  
Search Tree ◽  
Sphere Decoding ◽  
Mimo Channels ◽  
Single Node ◽  
Vast Number

Sphere Decoding (SD) algorithms can achieve a quasi-maximum likelihood (ML) decoder performance over Gaussian multiple input-multiple output (MIMO) channels with much lower complexity compared to the exhaustive search method. The SD algorithm is based on a closest lattice point search over a limited search space (hypersphere). On top of that, QR-decomposition simplifies the SD linear system's matrix to be an upper triangle matrix. The solution solver then is done by searching in the exponentially expanding search tree, started from the top with only a single node then increases by M times every level (in $N_T\times N_R$ MIMO system). Fortunately, the SD algorithm shrinks its hypersphere at every level (once the level node is determined) and phases out a vast number of the candidates, remaining only specific valid nodes in the current considered level. In this work, we proposed the statistical approach for evaluating the adequate number of valid search nodes at every level of the search tree, aiming to optimize the overall computational workload. We use a massive number of inputs patterns and extensive simulation to project the number of remaining valid nodes during the searching process. The simulations have been conducted for $4\times 4$ and $8\times 8$ MIMO systems. Our results indicate that for a particular targeted BER, choosing an appropriate sphere radius is essentially important and the number of necessary calculations increases only at the middle layer and can be generically quantified regardless of the system characteristics. This finding is beneficial for the hardware implementation of the SD, where the number of computational units has to be fixed in advance.

scholarly journals Improvement of Complexity and Performance of Least Square Based Channel Estimation in MIMO System

2016 ◽  
Vol 1 ◽  
pp. 11
Author(s):  
Anand Kumar Sah ◽  
Arun Kumar Timalsina
Keyword(s):  
Channel Estimation ◽  
Mimo Systems ◽  
Mimo System ◽  
Multiple Input Multiple Output ◽  
Estimation Method ◽  
Vital Role ◽  
Least Square ◽  
Mimo Channel ◽  
Fourth Generation ◽  
Simulation Results

<p>Multiple-input multiple-output (MIMO) systems play a vital role in fourth generation wireless systems to provide advanced data rate. In this paper, a better performance and reduced complexity channel estimation method is proposed for MIMO systems based on matrix factorization. This technique is applied on training based least squares (LS) channel estimation using STBC for performance improvement. Simulation results indicate that the proposed method not only alleviates the performance of MIMO channel estimation but also significantly reduces the complexity caused by matrix inversion. The performance evaluations are validated through computer simulations using MATLAB in terms of bit error rate (BER) for modified LS with LS and MMSE channel estimation techniques. Simulation results show that the BER performance and complexity of the proposed method clearly outperforms the conventional LS channel estimation method.</p><p><em>Journal of Advanced College of Engineering and Management, Vol. 1, 2015</em>, pp. 11-24</p>

scholarly journals Optimal signal mapping scheme for MIMO-BICM-ID transmission over the different fading channel using whale algorithm

2017 ◽  
Vol 7 (1.1) ◽  
pp. 106
Author(s):  
Vikas Nandal ◽  
Suresh Kumar
Keyword(s):  
Fading Channels ◽  
Iterative Decoding ◽  
Mimo System ◽  
Multiple Input Multiple Output ◽  
Design Criterion ◽  
Coded Modulation ◽  
Mimo Channel ◽  
Input Multiple Output ◽  
Bit Interleaved Coded Modulation ◽  
Mapping Scheme

The designing of signal mapping scheme for bit-interleaved coded modulation (BICM) systems has been received significant interest among the researchers recently due to the growing interest of using Multiple Input Multiple Output (MIMO) system. The bit-interleaved coded modulation systems are need of effective design in constellation mapping with iterative decoding that outperformed the existing BICM coding in time varying characteristics of the channel. In this paper, the design of optimal constellation mapping of the BICM system with iterative decoding for MIMO channel is proposed. Based on minimizing cost, a design criterion is proposed to find the optimal constellation mapping for an MIMO-BICM-ID system.  Here, a cost function is designed to search an optimal mapping scheme using the well-known optimization algorithm called, whale algorithm.  Using this method, we find some optimal constellation mapping for 2-dimensional and 3-dimensional cases. The designed technique is evaluated with the help of BER curve for different fading channels. 

scholarly journals Analysis of MIMO Receiver Using Generalized Least Squares Method in Colored Environments

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Mohamed Lassaad Ammari ◽  
Paul Fortier
Keyword(s):  
Least Squares ◽  
Additive Noise ◽  
Least Squares Method ◽  
Mimo Systems ◽  
Multiple Input Multiple Output ◽  
Generalized Least Squares ◽  
Mimo Channel ◽  
Mimo Channels ◽  
Detection Techniques ◽  
Generalized Least Squares Estimator

The classical detection techniques for multiple-input multiple-output (MIMO) systems are usually designed with the assumption that the additive complex Gaussian noise is uncorrelated. However, for closely spaced antennas, the additive noise is correlated due to the mutual antenna coupling. This letter analyzes an improved zero-forcing (ZF) technique for MIMO channels in colored environments. The additive noise is assumed to be correlated and the Rayleigh MIMO channel is considered doubly correlated. The improved ZF detector, based on the generalized least squares estimator (GLS), takes into account the noise covariance matrix and provides an unbiased estimator of the transmitted symbol vectors. We introduce some novel bounds on the achievable sum rate, on the normalized mean square error at the receiver output, and on the outage probability. The derived expressions are compared to Monte Carlo simulations.

scholarly journals Beamforming Using Exact Evaluation of Leakage and Ergodic Capacity of MU-MIMO System

Sensors ◽  
2021 ◽  
Vol 21 (20) ◽  
pp. 6792
Author(s):  
Ahmad Kamal Hassan ◽  
Muhammad Moinuddin
Keyword(s):  
Closed Form ◽  
Fading Channels ◽  
Quadratic Forms ◽  
Mimo Systems ◽  
Mimo System ◽  
Multiple Input Multiple Output ◽  
Ergodic Capacity ◽  
Leakage Rate ◽  
Telecommunication Networks ◽  
Indefinite Quadratic

Closed-form evaluation of key performance indicators (KPIs) of telecommunication networks help perform mathematical analysis under several network configurations. This paper deals with a recent mathematical approach of indefinite quadratic forms to propose simple albeit exact closed-form expressions of the expectation of two significant logarithmic functions. These functions formulate KPIs which include the ergodic capacity and leakage rate of multi-user multiple-input multiple-output (MU-MIMO) systems in Rayleigh fading channels. Our closed-form expressions are generic in nature and they characterize several network configurations under statistical channel state information availability. As a demonstrative example of the proposed characterization, the derived expressions are used in the statistical transmit beamformer design in a broadcast MU-MIMO system to portray promising diversity gains using standalone or joint maximization techniques of the ergodic capacity and leakage rate. The results presented are validated by Monte Carlo simulations.

scholarly journals Performance Analysis of TAS/SC as well as TAS/MRC MIMO Techniques under α-μ Fading Channels

2019 ◽  
Vol 8 (3) ◽  
pp. 3272-3277
Keyword(s):  
Fading Channels ◽  
Mimo Systems ◽  
Antenna Selection ◽  
Mimo System ◽  
Multiple Input Multiple Output ◽  
Maximal Ratio Combining ◽  
Selection Combining ◽  
Transmit Antenna Selection ◽  
Multiple Input ◽  
Input Multiple Output

Multiple-Input-Multiple-Output (MIMO) system improves performance as well as the capacity of the wireless system. The use of large number of antennas in a MIMO system increases the hardware complexities and also its price. To overcome this, MIMO systems that activate single transmit antenna at a time, namely transmit antenna selection (TAS) is considered in this paper. Selection combining (SC) and Maximal ratio combining (MRC) are carried out at the receiver over    fading channels. Expressions for outage probability and average bit error rate (ABER) are derived considering TAS/SC as well as TAS/MRC MIMO systems. All the derived expressions are validated by Monte-Carlo simulation results.

scholarly journals Analysis between Various Random MIMO Systems Model on the Basis of Channel Capacity

2016 ◽  
Author(s):  
Shree Krishna Acharya
Keyword(s):  
Outage Probability ◽  
Channel Capacity ◽  
Mimo Systems ◽  
Mimo System ◽  
Antenna System ◽  
System Model ◽  
Mimo Channel ◽  
Systems Model ◽  
Capacity Model ◽  
Transmitting Antenna

Finding a good MIMO system model also major issue in Wireless Communication system. It is facing with so many problem, one of the major problem is finding good system model in terms of capacity and transmitting antenna system. In this paper, we analyze the channel capacity of various MIMO system model with some constant SNR level and outage probability. We establish a novel idea for MIMO system models as consider as 2N- MIMO system model and find-out change in channel capacity when different transmitting antennas with constant SNR and outage probability. The channel capacity ratio CCR is presented here on the basis of 2N- MIMO channel capacity model. Number of transmitted antenna presented in MIMO system is increases is well-known however paper shows change in capacity in simple form.

scholarly journals Experimental Analysis of Concentrated versus Distributed Massive MIMO in an Indoor Cell at 3.5 GHz

Electronics ◽  
2021 ◽  
Vol 10 (14) ◽  
pp. 1646
Author(s):  
Jesús R. Pérez ◽  
Óscar Fernández ◽  
Luis Valle ◽  
Abla Bedoui ◽  
Mohamed Et-tolba ◽  
...  
Keyword(s):  
Massive Mimo ◽  
Mimo Systems ◽  
Mimo System ◽  
Multiple Input Multiple Output ◽  
Access Network ◽  
Base Station ◽  
Mimo Channel ◽  
Power Imbalance ◽  
Channel Measurements

This paper presents a measurement-based comparison between distributed and concentrated massive multiple-input multiple-output (MIMO) systems, which are called D-mMIMO and C-mMIMO systems, in an indoor environment considering a 400 MHz bandwidth centered at 3.5 GHz. In both cases, we have considered an array of 64 antennas in the base station and eight simultaneously active users. The work focuses on the characterization of both schemes in the up-link, considering the analysis of the sum capacity, the total spectral efficiency (SE) achievable by using the zero forcing (ZF) combining method, as well as the user fairness. The effect of the power imbalance between the different transmitters or user terminal (UT) locations, and thus, the benefits of performing an adequate power control are also investigated. The differences between the C-mMIMO and D-mMIMO channel performances are explained through the observation of the structure of their respective measured channel matrices through parameters such as the condition number or the power imbalance between the channels established by each UT. The channel measurements have been performed in the frequency domain, emulating a massive MIMO system in the framework of a time-domain duplex orthogonal frequency multiple access network (TDD-OFDM-MIMO). The characterization of the MIMO channel is based on the virtual array technique for both C-mMIMO and D-mMIMO systems. The deployment of the C-mMIMO and D-MIMO systems, as well as the distribution of users in the measurement environment, has been arranged as realistically as possible, avoiding the movement of people or machines.

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