scholarly journals Realistic antenna modeling for MIMO systems in microcell scenarios

2005 ◽  
Vol 2 ◽  
pp. 141-146
Author(s):  
C. Waldschmidt ◽  
C. Kuhnert ◽  
T. Fügen ◽  
W. Wiesbeck
Keyword(s):  
Antenna Arrays ◽  
Mutual Coupling ◽  
Mimo Systems ◽  
Mimo System ◽  
Cellular Systems ◽  
Handheld Devices ◽  
Communication Link ◽  
Cellular Phones ◽  
Power Budget ◽  
Spaced Antennas

Abstract. This paper shows the potential of MIMO in cellular systems, where small handheld devices are used for the terminals. A complete model of a MIMO communication link is used to integrate accurate antenna modelling into MIMO system simulations. All different effects of mutual coupling between closely spaced antennas are considered. The efficiency or power budget respectively of the antenna arrays in the terminals, which are influenced by mutual coupling effects, is taken into account. Capacity simulation results based on a channel obtained from ray-tracing simulations are shown with cellular phones with up to three Inverted-F antennas.

scholarly journals Capacity of fully correlated MIMO system using character expansion of groups

2005 ◽  
Vol 2005 (15) ◽  
pp. 2461-2471 ◽  
Author(s):  
Ejaz Khan ◽  
Conor Heneghan
Keyword(s):  
Antenna Arrays ◽  
Rayleigh Fading ◽  
Mimo Systems ◽  
Mimo System ◽  
Mimo Channel ◽  
Communication Link ◽  
Channel State ◽  
State Information ◽  
Perfect Channel State Information ◽  
Propagation Medium

It is well known that the use of antenna arrays at both sides of communication link can result in high channel capacities provided that the propagation medium is rich scattering. In most previous works presented on MIMO wireless structures, Rayleigh fading conditions were considered. In this work, the capacity of MIMO systems under fully correlated (i.e., correlations between rows and columns of channel matrix) fading is considered. We use replica method and character expansions to calculate the capacity of correlated MIMO channel in closed form. In our calculations, it is assumed that the receiver has perfect channel state information (CSI) but no such information is available at the transmitter.

scholarly journals Self-Interference Cancellation-Based Mutual-Coupling Model for Full-Duplex Single-Channel MIMO Systems

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Pawinee Meerasri ◽  
Peerapong Uthansakul ◽  
Monthippa Uthansakul
Keyword(s):  
Interference Cancellation ◽  
Mutual Coupling ◽  
Single Channel ◽  
Mimo Systems ◽  
Mimo System ◽  
Coupling Model ◽  
The Self ◽  
Full Duplex ◽  
Channel System ◽  
Interference Signals

The challenge of a full-duplex single-channel system is the method to transmit and receive signals simultaneously at the same time and on the same frequency. Consequently, a critical issue involved in such an operation is the resulting self-interference. Moreover, for MIMO system, the full-duplex single-channel system is subjected to the very strong self-interference signals due to multiple transmitting and receiving antennas. So far in the pieces of literature, there have not been any suitable techniques presented to reduce the self-interference for full-duplex single-channel MIMO systems. This paper initially proposes the method to cancel the self-interference by utilizing the mutual-coupling model for self-interference cancellation. The interference can be eliminated by using a preknown interference, that is, the mutual-coupling signals. The results indicate that the channel capacity performance of the proposed technique can significantly be improved due to the reduction of the self-interference power. The measurement results indicate that the proposed MIMO system can suppress the self-interference and mutual-interference signals with the reduction of 31 dB received power.

scholarly journals Angular Domain Data-Assisted Channel Estimation for Pilot Decontamination in Massive MIMO

2017 ◽  
Vol 2017 ◽  
pp. 1-9
Author(s):  
Yihenew Beyene ◽  
Kalle Ruttik ◽  
Riku Jäntti
Keyword(s):  
Channel Estimation ◽  
Antenna Arrays ◽  
Mean Squared Error ◽  
Mimo Systems ◽  
Mimo System ◽  
Base Station ◽  
Pilot Contamination ◽  
Angular Domain ◽  
Matrix Estimation ◽  
Minimum Mean Squared Error

Massive Multiple-Input-Multiple-Output (M-MIMO) system is a promising technology that offers to mobile networks substantial increase in throughput. In Time-Division Duplexing (TDD), the uplink training allows a Base Station (BS) to acquire Channel State Information (CSI) for both uplink reception and downlink transmission. This is essential for M-MIMO systems where downlink training pilots would consume large portion of the bandwidth. In densely populated areas, pilot symbols are reused among neighboring cells. Pilot contamination is the fundamental bottleneck on the performance of M-MIMO systems. Pilot contamination effect in antenna arrays can be mitigated by treating the channel estimation problem in angular domain where channel sparsity can be exploited. In this paper, we introduce a codebook that projects the channel into orthogonal beams and apply Minimum Mean-Squared Error (MMSE) criterion to estimate the channel. We also propose data-aided channel covariance matrix estimation algorithm for angular domain MMSE channel estimator by exploiting properties of linear antenna array. The algorithm is based on simple linear operations and no matrix inversion is involved. Numerical results show that the algorithm performs well in mitigating pilot contamination where the desired channel and other interfering channels span overlapping angle-of-arrivals.

scholarly journals Hybrid Precoding Design Using MMSE Baseband Precoder for mm-Wave Multi-User MIMO Systems

2019 ◽  
Vol 8 (2S11) ◽  
pp. 3486-3490
Keyword(s):  
Communication Networks ◽  
Antenna Arrays ◽  
Mimo Systems ◽  
Minimum Mean Square Error ◽  
Path Loss ◽  
Cellular Systems ◽  
Base Stations ◽  
System Capacity ◽  
Achievable Rate ◽  
Hybrid Precoding

For future 5G wireless communication networks, millimeter-wave (mmWave) cellular systems is considered to be the key enabling technology because of its high data rates, low latency, high system capacity, and huge available bandwidths. However, multiuser networks in mmWave frequency bands encounter high path loss and interference, thus degrading the performance. Applying large antenna arrays at the base stations (BS) in order to achieve high beamforming gains with the help of precoding techniques is an efficient way of improving the performance of the system. Although multi-user beamforming can improve spectral efficiencies, full digital beamforming strategies used in the conventional microwave systems increase the hardware cost and consumes high power for large number of antennas in mmW systems. In this paper, a low-complexity multi-user hybrid precoding structure is proposed for mmWave multiple input multiple output (MIMO) channels utilizing Minimum Mean Square Error (MMSE) precoders at the BS with perfect channel knowledge. Simulations show that the achievable rate obtained by the proposed hybrid precoding scheme is very close to the single-user rate and also performs better compared to other hybrid precoding approaches.

Performance Evaluation of Precoding Schemes for Multi User Massive MIMO System Over Nakagami-m Fading Channel

2021 ◽  
Author(s):  
Sultan.F Feisso Meko ◽  
Muluneh Mekonnen Tulu ◽  
Terefe Bahiru Bashu
Keyword(s):  
Performance Evaluation ◽  
Wireless Communication ◽  
Antenna Arrays ◽  
Interference Cancellation ◽  
Fading Channel ◽  
Massive Mimo ◽  
Mimo System ◽  
Base Station ◽  
Communication Link ◽  
User Interference

Abstract Nowadays, wireless communication system plays great roles in our dailyactivities and different improvements are requiring because the number of users increase from time to time. At the same time, users need high throughput and link reliability. The forthcoming generation of wireless communication will have to deal with some core requirements for serving large number of users simultaneously, upholdinghigh throughput for each user, assuring less energy consumption, etc. Inter-user interference has a major impact when a wireless communication link has a large number of users. To maintain a particular desired quality of service, sophisticated transmission mechanisms such as interference cancellation need be implemented. As a result, MU-massive MIMO with extremely huge antenna arrays is recommended. The term ”MU-massive MIMO” refers to a system with hundreds or thousands of antennas servicing tens of thousands of customers.Inter-user interference was greatly decreased once the channel vectors were closely orthogonal. As a result, high data rates can be supplied to multiple users at the same time. In this work, researcher investigated performance evaluation of a MU-massive MIMO utilizing different precoding schemes (like, MMSE, ZF, MRT) over nakagami-m fading channel with CSI at base station and users’ terminal. In addition, the researcher analyzed the outcome of pilot reuse factors and shaping (m) parameter.

scholarly journals Performance Analysis of 3D Massive MIMO Cellular Systems with Collaborative Base Station

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Xingwang Li ◽  
Lihua Li ◽  
Ling Xie ◽  
Xin Su ◽  
Ping Zhang
Keyword(s):  
Lower Bound ◽  
Massive Mimo ◽  
Mimo Systems ◽  
Mimo System ◽  
Base Station ◽  
Cellular Systems ◽  
Small Scale ◽  
Pilot Contamination ◽  
3D Mimo ◽  
Sum Rate

Massive MIMO have drawn considerable attention as they enable significant capacity and coverage improvement in wireless cellular network. However, pilot contamination is a great challenge in massive MIMO systems. Under this circumstance, cooperation and three-dimensional (3D) MIMO are emerging technologies to eliminate the pilot contamination and to enhance the performance relative to the traditional interference-limited implementations. Motivated by this, we investigate the achievable sum rate performance of MIMO systems in the uplink employing cooperative base station (BS) and 3D MIMO systems. In our model, we consider the effects of both large-scale and small-scale fading, as well as the spatial correlation and indoor-to-outdoor high-rise propagation environment. In particular, we investigate the cooperative communication model based on 3D MIMO and propose a closed-form lower bound on the sum rate. Utilizing this bound, we pursue a “large-system” analysis and provide the asymptotic expression when the number of antennas at the BS grows large, and when the numbers of antennas at transceiver grow large with a fixed ratio. We demonstrate that the lower bound is very tight and becomes exact in the massive MIMO system limits. Finally, under the sum rate maximization condition, we derive the optimal number of UTs to be served.

scholarly journals Capacity Optimization of MIMO Systems Involving Conformal Antenna Arrays using a Search Group Algorithm

2020 ◽  
Vol 5 (4) ◽  
pp. 209-214
Author(s):  
Abdelmadjid RECIOUI
Keyword(s):  
Wireless Communication ◽  
Antenna Arrays ◽  
Communication Systems ◽  
Mimo Systems ◽  
Mimo System ◽  
Wireless Communication Systems ◽  
Capacity Optimization ◽  
Mimo Communication ◽  
Conformal Antenna

MIMO systems constitute a backbone of the fourth and fifth generations of wireless communication systems. The purpose of this paper is to introduce the involvement of conformal antenna arrays into MIMO systems. The Search Group Algorithm (SGA) is then used to further enhance the capacity of MIMO system employing conformal antenna arrays at both ends (Transmitter; Tx and Receiver; Rx). The results reveal that compared to the linear and 2D cases, conformal antenna arrays promise higher capacity values which motivates their employment in future MIMO communication systems.

scholarly journals INVESTIGATION OF CAPACITY GAINS IN MIMO CORRELATED RICIAN FADING CHANNELS SYSTEMS

2013 ◽  
pp. 76-83
Author(s):  
NIRAV D. PATEL ◽  
VIJAY K. PATEL ◽  
DHARMESH SHAH
Keyword(s):  
Fading Channels ◽  
Antenna Arrays ◽  
Power Distribution ◽  
Mimo Systems ◽  
Rician Fading ◽  
Communication Link ◽  
Mimo Channels ◽  
Rician Fading Channel ◽  
Propagation Medium ◽  
Diversity Gains

This paper investigate the effect of Rician fading and correlation on the capacity and diversity of MIMO channels. The use of antenna arrays at both sides of the wireless communication link (MIMO systems) can increase channel capacity provided the propagation medium is rich scattering or Rayleigh fading and the antenna arrays at both sides are uncorrelated. However, the presence of line-of-sight (LOS) component and correlation of real world wireless channels may affect the system performance. Along with that we also investigate power distribution methods for higher capacity gains and effect of CSI at the transmitter on the capacity for range of SNR. Our investigation follows capacity gain as function of number of antennas and signal-to-noise (SNR) power ratio Block and frequency nonselective Rician fading channel is assumed, and the effect of Rician factor (L) and the correlation parameter (ρ) on the capacity and diversity gains of MIMO channels are found. Index.

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 Mutual Coupling Reduction In Microstrip Patch Antenna Arrays Using Simple Microstrip Resonator

2021 ◽  
Author(s):  
Saeed Roshani ◽  
Haniaisieh Shahv
Keyword(s):  
Antenna Arrays ◽  
Mutual Coupling ◽  
Mimo Systems ◽  
Coupling Effect ◽  
Mutual Effect ◽  
Surface Current ◽  
Patch Antennas ◽  
Microstrip Resonator ◽  
Microstrip Patch Antennas ◽  
Microstrip Patch

Abstract In this paper a novel ladder resonator is introduced to decrease mutual coupling effect between two microstrip patch antennas. Applied patch antennas are operating at 2.45 GHz frequency (ISM band), which specially used for multiple-input–multiple-output (MIMO) systems. The edge-to-edge distance between two microstrip patch antennas is 0.05 λ. The proposed ladder resonator impressively blocks the surface current between two patch antennas at the operating frequency, which results in mutual effect reduction. The proposed configuration has been fabricated and tested. Scattering parameters with and without of proposed resonator has been investigated. The results show that, the proposed configuration increases isolation between two microstrip patch antennas about 42dB.

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