scholarly journals Analysis of MIMO-OFDM: Effect of Mutual Coupling, Frequency Response, SNR and Channel Capacity

YMER Digital ◽  
2021 ◽  
Vol 20 (10) ◽  
pp. 118-126
Author(s):  
Karthik Kumar Vaigandla ◽  
◽  
RadhaKrishna Karne ◽  
Allanki Sanyasi Rao ◽  
◽  
...  
Keyword(s):  
Frequency Response ◽  
Antenna Arrays ◽  
Mimo Systems ◽  
Spatial Multiplexing ◽  
Maximum Efficiency ◽  
Systematic Analysis ◽  
High Data ◽  
Mimo Ofdm ◽  
And Performance ◽  
Wireless Communications Systems

Systematic analysis of systems with Multiple Inputs and Multiple Outputs (MIMO) is presented in this paper. MIMO systems and various techniques for decoupling are discussed, including their effect on performance. As wireless communications systems progress, the challenge is to deliver high-data-rate access with good quality of service (QOS). MIMO technology can also offer greater reliability by boosting the link due to increased spectral efficiency; this can be met by incorporating spatial multiplexing gains and antenna diversity gains. OFDM signals can be used with antenna arrays at both transmitter and receiver for maximum efficiency. As a result, we have MIMO-OFDM. A generalized predictive control for MIMO systems is considered in this paper. Stability and performance of the closed-loop system are measured by using frequency response indicators.

scholarly journals On the Probability of Erasure for MIMO-OFDM

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Kasturi Vasudevan ◽  
A. Phani Kumar Reddy ◽  
Gyanesh Kumar Pathak ◽  
Shivani Singh
Keyword(s):  
Fading Channels ◽  
Communication Systems ◽  
Mimo Systems ◽  
Multiple Input Multiple Output ◽  
Spatial Multiplexing ◽  
Main Requirement ◽  
Valid Signal ◽  
Input Multiple Output ◽  
Mimo Ofdm ◽  
Wireless Standards

Detecting the presence of a valid signal is an important task of a telecommunication receiver. When the receiver is unable to detect the presence of a valid signal, due to noise and fading, it is referred to as an erasure. This work deals with the probability of erasure computation for orthogonal frequency division multiplexed (OFDM) signals used by multiple input multiple output (MIMO) systems. The theoretical results are validated by computer simulations. OFDM is widely used in present day wireless communication systems due to its ability to mitigate intersymbol interference (ISI) caused by frequency selective fading channels. MIMO systems offer the advantage of spatial multiplexing, resulting in increased bit-rate, which is the main requirement of the recent wireless standards like 5G and beyond.

scholarly journals On the Comparison of Various Overhead Arrangements for Massive MIMO-OFDM Channel Estimation

2014 ◽  
Vol 60 (2) ◽  
pp. 173-179 ◽  
Author(s):  
Pallaviram Sure ◽  
Chandra Mohan Bhuma
Keyword(s):  
System Reliability ◽  
Massive Mimo ◽  
Orthogonal Frequency Division Multiplexing ◽  
Mimo Systems ◽  
Cyclic Prefix ◽  
Doppler Spectrum ◽  
Ofdm Systems ◽  
Ofdm System ◽  
High Data ◽  
Mimo Ofdm

Abstract Massive multi input multi output (MIMO) systems incorporate orthogonal frequency division multiplexing (OFDM) technology to render high data rate services for future wireless communication applications. The channel estimator (CE) employed by a reliable massive MIMO-OFDM system requires huge amount of overhead in the form of known and null data transmissions, hence limiting the system spectral efficiency (SE). Often, CE design is a tradeoff between SE and system reliability. In this paper, CE with three different overhead arrangements, namely time domain synchronous (TDS), comb type with cyclic prefix (CTCP), 2D grid type with cyclic prefix (GTCP) are investigated and a GTCP based CE is proposed which offers both high SE and improved system reliability. The proposed CE uses autocorrelation based denoising threshold for channel impulse response (CIR) estimation and does not require any knowledge of channel statistics (KCS). A 4 x 16 MIMO-OFDM system is simulated in a rayleigh fading channel environment with U-shaped doppler spectrum. From the bit error rate (BER) performance results inWiMax SUI-4, Advanced Television Technology Center (ATTC) and Brazil A channel environments, it is verified that the proposed CE with GTCP overhead and proposed denoising scheme, indeed improves both SE and system reliability. Hence it is suitable for application in all massive MIMO-OFDM systems.

scholarly journals Performance of WiMAX Physical layer MIMO-OFDM System under Rayleigh Fading Channel

2019 ◽  
Vol 9 (2S3) ◽  
pp. 269-273
Keyword(s):  
Rural Areas ◽  
Orthogonal Frequency Division Multiplexing ◽  
Low Cost ◽  
Multiple Input Multiple Output ◽  
Physical Layer ◽  
Spatial Multiplexing ◽  
System Level ◽  
High Data ◽  
Mimo Ofdm ◽  
Phy Layer

WiMAX infrastructure will meet the needs of multiple consumers at very low cost and without the time required to install a wired network, for those who need quick access to rural areas where cable systems cannot be feasible because of the distances and costs involved. Multi-Input (MIMO) technology in combination with orthogonal frequency-division multiplexing (MIMO-OFDM) is an appealing architecture for wireless systems of the next decade. This system level approach has been used in many WiMAX simulator developments, both public and private. In this paper we are investigating the performance of Wi- MAX PHY layer for PHY-layer modifications of 2×2 MIMO (multiple-input multiple-output), spatial multiplexing, to provide high throughput, bandwidth efficiency and low bit error rate at high data rates. The paper provides necessary description for the simulation process of WiMAX model, addresses the important elements for specific inaccuracies that are existed in the physical layer with the BER for various modulation schemes.

scholarly journals PAPR Reduction in MIMO-OFDM Using Modified PTS Scheme With Hybride ABC-FF Algorithem

2018 ◽  
Vol 7 (4.5) ◽  
pp. 423
Author(s):  
K. Aruna Kumari ◽  
Dr. K. Sri Rama Krishna
Keyword(s):  
Antenna Arrays ◽  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
System Capacity ◽  
Papr Reduction ◽  
Partial Transmit Sequence ◽  
High Data ◽  
In Series ◽  
Mimo Ofdm ◽  
Selective Mapping

Orthogonal Frequency Division Multiplexing (OFDM) is an admired method for high data rate wireless transmission. OFDM can be clubbed with antenna arrays at the transmitter and receiver to increase diversity gain to enhance the system capacity on time variant and frequency selective channels, resulting in (Multi input and Multi output)MIMO. One main flaw of MIMO-OFDM is that the signals transmitted on different antennas might exhibit a prohibitively large Peak-to-Average Power Ratio (PAPR). There are two techniques mainly used to mitigate the effect of PAPR namely Partial Transmit Sequence (PTS) and Selective Mapping (SLM). In this paper a new optimized Partial Transmit Sequence (PTS) scheme and SLM for PAPR reduction in MIMO-OFDM have been proposed. Both the techniques are connected in series to get efficient throughput. Hybrid of ABC–FF algorithm has been intended for optimal phase factor. The proposed technique has achieved better results than existing techniques. This intended technique has been implemented on the working platform of MATLAB.  

scholarly journals Impact of Mutual Coupling and Polarization of Antennas on BER Performances of Spatial Multiplexing MIMO Systems

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Jianfeng Zheng ◽  
Yue Li ◽  
Zhenghe Feng
Keyword(s):  
Antenna Array ◽  
Antenna Arrays ◽  
Mutual Coupling ◽  
Mimo Systems ◽  
Multiple Input Multiple Output ◽  
Spatial Multiplexing ◽  
Polarization Diversity ◽  
Matching Networks ◽  
Diversity Antenna ◽  
Ber Performance

This paper is aimed at studying the impacts of mutual coupling, matching networks, and polarization of antennas on performances of Multiple-Input Multiple-Output (MIMO) systems employing Spatial Multiplexing (SM). In particular, the uncoded average Bit Error Rate (BER) of MIMO systems is investigated. An accurate signal analysis framework based on circuit network parameters is presented to describe the transmit/receive characteristics of the matched/unmatched antenna array. The studied arrays consist of matched/unmatched compact copolarization and polarization diversity antenna array. Monte-Carlo numerical simulations are used to study the BER performances of the SM MIMO systems using maximum-likelihood and/or zero-forcing detection schemes. The simulation results demonstrate that the use of matching networks can improve the BER performance of SM MIMO systems significantly, and the BER performance deterioration due to antenna orientation randomness can be compensated by use of polarization diversity antenna arrays.

scholarly journals MIMO performance of a planar logarithmically periodic antenna with respect to measured channel matrices

2008 ◽  
Vol 6 ◽  
pp. 55-61
Author(s):  
H. Rabe ◽  
D. Kornek ◽  
M. Stege ◽  
I. Rolfes
Keyword(s):  
Outage Probability ◽  
Communication Systems ◽  
Mimo Systems ◽  
Multiple Input Multiple Output ◽  
Research Area ◽  
Wide Frequency Range ◽  
Spatial Multiplexing ◽  
High Data ◽  
Data Rates ◽  
Input Multiple Output

Abstract. The increasing interest in wireless transmission of highest data rates for multimedia applications (e.g. HDTV) demands the use of communication systems as e.g. described in the IEEE 802.11n draft specification for WLAN including spatial multiplexing or transmit diversity to achieve a constant high data rate and a small outage probability. In a wireless communications system the transmission of parallel data stream leads to multiple input/multiple output (MIMO) systems, whose key parameters heavily depend on the properties of the mobile channel. Assuming an uncorrelated channel matrix the correlation between the multiplexed data streams is caused by the coupling of the antennas, so that the radiation element becomes an even more important part of the system. Previous work in this research area (Klemp and Eul, 2006) has shown that planar log.-per four arm antennas are promising candidates for MIMO applications providing two nearly decorrelated radiators, which cover a wide frequency range including both WLAN bands at 2.4 GHz and 5.4 GHz. Up to now the MIMO performance of this antenna is mainly analyzed by simulations. In this contribution measured channel matrices in a real office environment are studied in terms of the antenna's MIMO performance such as outage probability. The obtained results recorded by using a commercial platform are compared to the simulated ones.

Approaches to estimating the efficiency and performance of the trade enterprise activity: modern view

2019 ◽  
pp. 71-77
Author(s):  
Lyudmyla Shymanovska-Dianych ◽  
Nataliya Pedchenko
Keyword(s):  
Market Economy ◽  
Continuous Improvement ◽  
Systematic Analysis ◽  
Modern View ◽  
And Performance ◽  
Enterprise Activity

In the article, the existing variety of terms of "efficiency" and "performance" is structured and the features of each concept and the differences between them are defined. The article proves that it is necessary to divide the categories "performance" and "efficiency" for trade enterprises. Each of them has an independent value, equally important for the evaluation of their activities, and can not replace another concept. The authors prove that in a market economy, when the results of the work of some market actors depend on the clarity and coherence of the work of other actors, the problem of efficiency becomes decisive. The article argues that the key to the success of any enterprise, including commercial ones, lies in the continuous improvement of the efficiency and performance of their activities, systematic analysis, development and implementation of measures aimed at increasing its efficiency and performance. The approaches to assessing the efficiency and performance of the enterprise, which most fully cover the key criteria for assessing the efficiency and performance of different enterprises, are analyzed. Despite the obvious differences below the described approaches, they do not exclude each other, but only characterize the operation of the enterprise from different sides. These approaches are based on certain indicators by means of which the analysis, comparison and evaluation of the enterprise is carried out. The authors prove that this system of indicators is not ideal and does not take into account all characteristics of trade enterprises, which influence the efficiency and performance of their activities. Therefore, they suggest expanding this list, adding such indicators as an indicator of the overall assessment of the economic profitability of a trade company, the indicator of the effectiveness of the use of retail space and indirect indicators of profitability.

Grouped Multiuser Diversity for Spatial Multiplexing MIMO Systems

2011 ◽  
Vol 30 (1) ◽  
pp. 81-85
Author(s):  
Er-lin Zeng ◽  
Shi-hua Zhu ◽  
Xue-wen Liao ◽  
Jun Wang
Keyword(s):  
Mimo Systems ◽  
Multiuser Diversity ◽  
Spatial Multiplexing

MIMO Systems in a Composite Fading and Generalized Noise Scenario: A Review

2020 ◽  
Vol 14 ◽  
Author(s):  
Keerti Tiwari
Keyword(s):  
System Performance ◽  
Performance Enhancement ◽  
Channel Model ◽  
Mimo Systems ◽  
Mimo System ◽  
Spatial Diversity ◽  
Spatial Multiplexing ◽  
Channel Models ◽  
Efficient System ◽  
Composite Channel

: Multiple-input multiple-output (MIMO) systems have been endorsed to enable future wireless communication requirements. The efficient system designing appeals an appropriate channel model, that considers all the dominating effects of wireless environment. Therefore, some complex or less analytically acquiescent composite channel models have been proposed typically for single-input single-output (SISO) systems. These models are explicitly employed for mobile applications, though, we need a specific study of a model for MIMO system which can deal with radar clutters and different indoor/outdoor and mobile communication environments. Subsequently, the performance enhancement of MIMO system is also required in such scenario. The system performance enhancement can be examined by low error rate and high capacity using spatial diversity and spatial multiplexing respectively. Furthermore, for a more feasible and practical system modeling, we require a generalized noise model along with a composite channel model. Thus, all the patents related to MIMO channel models are revised to achieve the near optimal system performance in real world scenario. This review paper offers the methods to improve MIMO system performance in less and severe fading as well as shadowing environment and focused on a composite Weibull-gamma fading model. The development is the collective effects of selecting the appropriate channel models, spatial multiplexing/detection and spatial diversity techniques both at the transmitter and the receivers in the presence of arbitrary noise.

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