scholarly journals A Flexible FPGA-Based Channel Emulator for Non-Stationary MIMO Fading Channels

2020 ◽  
Vol 10 (12) ◽  
pp. 4161
Author(s):  
Qiuming Zhu ◽  
Wei Huang ◽  
Kai Mao ◽  
Weizhi Zhong ◽  
Boyu Hua ◽  
...  
Keyword(s):  
Fading Channels ◽  
Channel Model ◽  
Multiple Input Multiple Output ◽  
Mimo Channel ◽  
Channel Fading ◽  
Power Delay Profile ◽  
Channel Emulator ◽  
Field Programmable ◽  
Fpga Chip ◽  
Doppler Power

In this paper, a discrete non-stationary multiple-input multiple-output (MIMO) channel model suitable for the fixed-point realization on the field-programmable gate array (FPGA) hardware platform is proposed. On this basis, we develop a flexible hardware architecture with configurable channel parameters and implement it on a non-stationary MIMO channel emulator in a single FPGA chip. In addition, an improved non-stationary channel emulation method is employed to guarantee accurate channel fading and phase, and the schemes of other key modules are also illustrated and implemented in a single FPGA chip. Hardware tests demonstrate that the output statistical properties of proposed channel emulator, i.e., the probability density function (PDF), cross-correlation function (CCF), Doppler power spectrum density (DPSD), and the power delay profile (PDP) agree well with the corresponding theoretical ones.

scholarly journals MIMO Fading Emulator Development with FPGA and Its Application to Performance Evaluation of Mobile Radio Systems

2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
Yoshio Karasawa ◽  
Katsuhiro Nakada ◽  
Guijiang Sun ◽  
Rikako Kotani
Keyword(s):  
Channel Model ◽  
Multiple Input Multiple Output ◽  
New Developments ◽  
Performance Limit ◽  
Stage Scheme ◽  
Mobile Radio Systems ◽  
Multiple Input ◽  
Field Programmable ◽  
Input Multiple Output ◽  
Radio Systems

We present four new developments for a multiple-input multiple-output (MIMO) over-the-air measurement system based on our previous studies. The first two developments relate to the channel model for multipath environment generation. One is a further simplification of the circuit configuration without performance degradation by reducing the number of delay generation units, which dominate the performance limit when implementing the circuit on a field-programmable gate array (FPGA). The other is to realize spatial correlation characteristics among the input ports on the transmission side, whereas the previously proposed channel model did not consider this correlation. The third development involves the details of implementing the MIMO fading emulator on an FPGA as a two-stage scheme. The fourth is the demonstration of application examples of the developed system.

scholarly journals MIMO Self-Encoded Spread Spectrum with Iterative Detection over Rayleigh Fading Channels

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Shichuan Ma ◽  
Lim Nguyen ◽  
Won Mee Jang ◽  
Yaoqing (Lamar) Yang
Keyword(s):  
Fading Channels ◽  
Spread Spectrum ◽  
Rayleigh Fading ◽  
Mimo Systems ◽  
Signal To Noise Ratio ◽  
Multiple Input Multiple Output ◽  
Spatial Diversity ◽  
Iterative Detection ◽  
Channel Fading ◽  
Input Multiple Output

Self-encoded spread spectrum (SESS) is a novel communication technique that derives its spreading code from the randomness of the source stream rather than using conventional pseudorandom noise (PN) code. In this paper, we propose to incorporate SESS in multiple-input multiple-output (MIMO) systems as a means to combat against fading effects in wireless channels. Orthogonal space-time block-coded MIMO technique is employed to achieve spatial diversity, and the inherent temporal diversity in SESS modulation is exploited with iterative detection. Simulation results demonstrate that MIMO-SESS can effectively mitigate the channel fading effect such that the system can achieve a bit error rate of with very low signal-to-noise ratio, from 3.3 dB for a antenna configuration to just less than 0 dB for a configuration under Rayleigh fading. The performance improvement for the case is as much as 6.7 dB when compared to an MIMO PN-coded spread spectrum system.

Research on Improvement of the Next Generation IEEE802.11ac Channel Model

2013 ◽  
Vol 712-715 ◽  
pp. 1741-1745
Author(s):  
Hao Cai ◽  
Dan Ao Han
Keyword(s):  
Wireless Local Area Network ◽  
Channel Model ◽  
Local Area Network ◽  
Local Area ◽  
Task Group ◽  
Mimo Channel ◽  
Area Network ◽  
Power Delay Profile ◽  
Ieee 802.11Ac ◽  
Set Up

Based on the special correlation of antennas and the power delay profile (PDP) of the cluster model, six models of A-F have been established by the TGn task-group in total. On the basis of the new broadband wireless local area network (WLAN) standard--IEEE 802.11ac with larger bandwidth and multi-user requirements drawn up by the TGac task-group, in this paper, the IEEE 802.11ac channel model is set up by means of improving and simulating the indoor MIMO channel.

scholarly journals An Investigation of Self-Interference Reduction Strategy in a Spatially Correlated MIMO Channel

2012 ◽  
Vol 2012 ◽  
pp. 1-10
Author(s):  
Rosdiadee Nordin
Keyword(s):  
Fading Channels ◽  
Multiple Input Multiple Output ◽  
Spatial Multiplexing ◽  
Mimo Channel ◽  
Limiting Factor ◽  
Subcarrier Allocation ◽  
Spatially Correlated ◽  
High Data ◽  
Correlated Channels ◽  
Wide Range

One of the efficient ways to transmit high data rate is by employing a multiple-input multiple-output (MIMO) transmission. One of the MIMO schemes, known as spatial multiplexing (SM), relies on the linear independence data streams from different transmit antennas to exploit the capacity from the fading channels. Consequently, SM suffers from the effect of spatial correlation which is the limiting factor in achieving the capacity benefit that SM can offer. In an attempt to increase the robustness of the SM transmission in a wide range of correlated channels, the use of dynamic subcarrier allocation (DSA) is investigated. The effective signal-to-interference-and-noise ratio (SINR) metric is used as the performance metric to determine the subcarrier quality which can then be utilised in the allocation. Two novel variants of the subcarrier allocation scheme are proposed. It is shown that the DSA-SINR approach improves the BER performance of SM transmission in highly correlated channels 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 Use Hierarchical Codebook to Improve the Primary User Detection in the Cognitive Radio’s Cooperative Spectrum Sensing

2021 ◽  
Vol 5 (6) ◽  
pp. 22-28
Author(s):  
Hoai Trung Tran
Keyword(s):  
Spectrum Sensing ◽  
Channel Model ◽  
Cooperative Spectrum Sensing ◽  
Signal To Noise Ratio ◽  
Multiple Input Multiple Output ◽  
Primary User ◽  
Mimo Channel ◽  
High Signal ◽  
Secondary Users ◽  
Input Multiple Output

Currently, the cognitive network is receiving much attention due to the advantages it brings to users. An important method in cognitive radio networks is spectrum sensing, as it allows secondary users (SUs) to detect the existence of a primary user (PU). Information of probability of false detection or warning about the PU is sent to a fusion center (FC) by the SUs, from which the FC will decide whether or not to allow the SUs to use the PU spectrum to obtain information. The transmission of information with a high signal to noise ratio (SNR) will increase the FC's ability to detect the existence of the PU. However, researchers are currently focusing on probabilistic formulas assuming that the channel is known ideally or there is nominal channel information at the FC; moreover, one model where the FC only knows the channel correlation matrix. Furthermore, studies are still assuming this is a simple multiple input – multiple output (MIMO) channel model but do not pay much attention to the signal processing at the transmitting and receiving antennas between the SUs and the FCs. A new method introduced in this paper when combining beamforming and hierarchical codebook makes the ability to detect the existence of the PU at the FC significantly increased compared to traditional methods.

scholarly journals A Semiempirical MIMO Channel Model in Obstructed Viaduct Scenarios on High-Speed Railway

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Tao Zhou ◽  
Cheng Tao ◽  
Liu Liu ◽  
Zhenhui Tan
Keyword(s):  
High Speed ◽  
Channel Model ◽  
Mimo Systems ◽  
Multiple Input Multiple Output ◽  
Time Correlation ◽  
Time Correlation Function ◽  
Mimo Channel ◽  
High Speed Railway ◽  
Single Input Single Output ◽  
Single Output

A semiempirical multiple-input multiple-output (MIMO) channel model is proposed for high-speed railway (HSR) viaduct scenarios. The proposed MIMO model is based on the combination of realistic single-input single-output (SISO) channel measurement results and a theoretical geometry-based stochastic model (GBSM). Temporal fading characteristics involvingK-factor and Doppler power spectral density (PSD) are derived from the wideband measurement under an obstructed viaduct on Zhengzhou-Xi’an HSR in China. The GBSM composed of a one-ring model and an elliptical model is employed to describe the entire propagation environment. Environment-related parameters in the GBSM are determined by the measured temporal fading properties. And a close agreement is achieved between the model results and measured data. Finally, a deterministic simulation model is established to perform the analysis of the space-time correlation function, the space-Doppler PSD, and the channel capacity for the measured scenario. This model is more realistic and particularly beneficial for the performance evaluation of MIMO systems in HSR environments.

scholarly journals Effects of Synchronization Errors on Wavelet-based CR-OFDM Systems in Doubly Selective Fading Channels

2021 ◽  
Author(s):  
ARJUN KETHUPURA RANGASWAMY ◽  
Surekha T P
Keyword(s):  
Fading Channels ◽  
Cognitive Radios ◽  
Channel Fading ◽  
Ofdm Systems ◽  
Local Oscillators ◽  
Power Delay Profile ◽  
Doubly Selective Channel ◽  
Time Frequency ◽  
Synchronization Errors ◽  
Selective Channel

Abstract The Major Setback of a Multi-Carrier Modulation (MCM) is Synchronization Errors, which includes time, frequency and phase offset. Especially, Wavelet based MCM catches the eyes of researchers due to its flexibilities which are seen as one of the strong contender for Cognitive Radios. Synchronization errors are mainly due to mobility between nodes and sub-optimal local oscillators and it is necessary to learn the behavior of wavelets under these channel fading conditions. In this paper, we present the joint effects of Wavelet-based Cognitive Radio OFDM (CR-WOFDM) systems under Synchronization Error in terms of based bit error rate (BER). BER Outputs of WOFDM is compared with FFT based OFDM with Cyclic Prefix (CP-OFDM) systems in a doubly-selective channel by designing a communication system for computer simulation. Several well-known wavelets are chosen and analyzed, including Daubechies (db), Symlets (sym), Coiflets (coif), Fejér-Korovkin (fk) filters, and biorthogonal (bior) wavelets. First, we show the behavior of wavelets in terms of BER by considering different doubly selective channel Power Delay Profile (PDP) like, AWGN, FLAT, Pedestrian and Vehicular and channel Doppler models like, Uniform and JAKES. Finally, we calculate and plot Signal-to-Interference Ratio (SIR) of WOFDM with Time and Frequency Offset and compared the results with FFT based CP-OFDM.

scholarly journals Analytical Nonstationary 3D MIMO Channel Model for Vehicle-to-Vehicle Communication on Slope

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Kaizhen Liu ◽  
Zaixue Wei ◽  
Sibo Chen
Keyword(s):  
Communication Systems ◽  
Channel Model ◽  
Multiple Input Multiple Output ◽  
Measurement Data ◽  
Special Kind ◽  
Mimo Channel ◽  
Future Research ◽  
Vehicle Communication ◽  
Vehicle To Vehicle ◽  
Vehicle To Vehicle Communication

Vehicle-to-vehicle communication plays a strong role in modern wireless communication systems, appropriate channel models are of great importance in future research, and propagation environment with slope is one special kind. In this study, a novel three-dimensional nonstationary multiple-input multiple-output channel model for the sub-6 GHz band is proposed. This model is a regular-shaped multicluster geometry-based analytical model, and it combines the line-of-sight component and multicluster scattering rays as the nonline-of-sight components. Each cluster of scatterers represents the influence of different moving vehicles on or near a slope, and scatterers are, respectively, distributed within two spheres around the transmitter and the receiver. In this model, it is considered that the azimuth and elevation angles of departure and arrival are jointly distributed and conform to the von Mises–Fisher distribution, which can easily control the range and concentration of the scatterers within spheres to mimic the real-world situation well. Moreover, the impulse response and the autocorrelation function of the corresponding channel is derived and proposed; then, the Doppler power spectrum density of the channel is simulated and analyzed. In addition, the nonstationary characteristics of the presented channel model are observed through simulations. Finally, the simulation results are compared with measurement data in order to validate the utility of the proposed model.

scholarly journals Hybrid Beamforming Analysis Based on MIMO Channel Measurements at 28 GHz

2020 ◽  
Author(s):  
Joerg Eisenbeis ◽  
Magnus Tingulstad ◽  
Nicolai Kern ◽  
Zsolt Kollár ◽  
Jerzy Kowalewski ◽  
...  
Keyword(s):  
Communication Systems ◽  
Channel Model ◽  
Multiple Input Multiple Output ◽  
Wireless Channel ◽  
Mimo Channel ◽  
Channel Measurements ◽  
Electromagnetic Propagation ◽  
Channel Models ◽  
Input Multiple Output ◽  
Hybrid Beamforming

<div>Hybrid beamforming systems represent an efficient</div><div>architectural solution to realize massive multiple-input multiple-output (MIMO) communication systems in the centimeter wave (cmW) and millimeter wave (mmW) region. These hybrid beamforming systems separate the beamforming process into a digital and analog beamforming network. The analog beamforming networks can be realized by different architectural solutions, which demand dedicated algorithms to determine the complex weighting factors in the digital and analog domain. To date, novel hybrid beamforming architectures and algorithms are solely compared in numerical simulations based on statistical channel models. These abstract channel models simplify the complicated electromagnetic propagation process, thereby not exactly reconstructing the wireless channel. Within this work, we present a measurement-based evaluation of hybrid beamforming algorithms and compare them with numerical results gained from a statistical path-based MIMO channel model. The results show that by adjustment of the channel model parameter the simulation achieves a good match with the measured maximum achievable spectral efficiencies.</div>

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