A Scalable Wireless Channel Emulator for Broadband MIMO Systems

2007 ◽  
Author(s):  
H. Eslami ◽  
A. M. Eltawil
Keyword(s):  
Mimo Systems ◽  
Wireless Channel ◽  
Channel Emulator

scholarly journals Joint Design of Massive MIMO Precoder and Security Scheme for Multiuser Scenarios under Reciprocal Channel Conditions

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Gustavo Anjos ◽  
Daniel Castanheira ◽  
Adão Silva ◽  
Atílio Gameiro ◽  
Marco Gomes ◽  
...  
Keyword(s):  
Channel Capacity ◽  
Massive Mimo ◽  
Mimo Systems ◽  
Mimo System ◽  
Wireless Channel ◽  
Joint Design ◽  
Security Scheme ◽  
Working Principle ◽  
Transmitted Signal ◽  
Intended Receiver

The exploration of the physical layer characteristics of the wireless channel is currently the object of intensive research in order to develop advanced secrecy schemes that can protect information against eavesdropping attacks. Following this line of work, in this manuscript we consider a massive MIMO system and jointly design the channel precoder and security scheme. By doing that we ensure that the precoding operation does not reduce the degree of secrecy provided by the security scheme. The fundamental working principle of the proposed technique is to apply selective random rotations in the transmitted signal at the antenna level in order to achieve a compromise between legitimate and eavesdropper channel capacities. These rotations use the phase of the reciprocal wireless channel as a common random source between the transmitter and the intended receiver. To assess the security performance, the proposed joint scheme is compared with a recently proposed approach for massive MIMO systems. The results show that, with the proposed joint design, the number of antenna elements does not influence the eavesdropper channel capacity, which is proved to be equal to zero, in contrast to previous approaches.

scholarly journals Practical and Simple Wireless Channel Models for Use in Multipolarized Antenna Systems

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
KwangHyun Jeon ◽  
Xin Su ◽  
Bing Hui ◽  
KyungHi Chang
Keyword(s):  
Channel Model ◽  
Mimo Systems ◽  
Wireless Channel ◽  
Spatial Multiplexing ◽  
Channel Models ◽  
Data Rates ◽  
Outdoor Environments ◽  
Wireless Channel Models ◽  
2D And 3D ◽  
Antenna Systems

The next-generation wireless systems are expected to support data rates of more than 100 Mbps in outdoor environments. In order to support such large payloads, a polarized antenna may be employed as one of the candidate technologies. Recently, the third generation partnership standards bodies (3GPP/3GPP2) have defined a cross-polarized channel model in SCM-E for MIMO systems; however, this model is quite complex since it considers a great many channel-related parameters. Furthermore, the SCM-E channel model combines the channel coefficients of all the polarization links into one complex output, making it impossible to exploit the MIMO spatial multiplexing or diversity gains in the case of employing polarized antenna at transmitter and receiver side. In this paper, we present practical and simple 2D and 3D multipolarized multipath channel models, which take into account both the cross-polarization discrimination (XPD) and the Rician factor. After verifying the proposed channel models, the BER and PER performances and throughput using the EGC and MRC combining techniques are evaluated in multipolarized antenna systems.

scholarly journals Space-Time Trellis Coding with Equalization

2019 ◽  
Vol 4 (9) ◽  
pp. 207-211
Author(s):  
Ibukunoluwa Adetutu Adebanjo ◽  
Yekeen Olajide Olasoji ◽  
Micheal Olorunfunmi Kolawole
Keyword(s):  
Mean Squared Error ◽  
Mimo Systems ◽  
Multiple Input Multiple Output ◽  
Space Time ◽  
Wireless Channel ◽  
Cyclic Prefix ◽  
Single Carrier ◽  
Minimum Mean Squared Error ◽  
Mmse Receiver ◽  
Input Multiple Output

As we are entering the 5G era, high demand is made of wireless communication. Consistent effort has been ongoing in multiple-input multiple-output (MIMO) systems, which provide correlation on temporal and spatial domain, to meet the high throughput demand. To handle the characteristic nature of wireless channel effectively and improve the system performance, this paper considers the combination of diversity and equalization. Space-Time trellis code is combined with single-carrier modulation using two-choice equalization techniques, namely: minimum mean squared error (MMSE) equalizer and orthogonal triangular (QR) detection. MMSE gives an optimal balance between noise enhancement and net inter-symbol interference (ISI) in the transmitted signal. Use of these equalizers provides the platform of investigating the bit error rate (BER) and the pairwise error probability (PEP) at the receiver, as well as the effect of cyclic prefix reduction on the receivers. It was found that the MMSE receiver outperforms the QR receiver in terms of BER, while in terms of PEP; the QR receiver outperforms the MMSE receiver. When a cyclic prefix reduction test was carried out on both receivers, it yields a significant reduction in BER of both receivers but has no significant effect on the overall performance.

scholarly journals Linear detectors and precoding methods for massive MIMO

2021 ◽  
Vol 42 (2) ◽  
pp. 209
Author(s):  
Jean Marcel Faria Tonin ◽  
Taufik Abrao
Keyword(s):  
Massive Mimo ◽  
Communication Systems ◽  
Mean Squared Error ◽  
Mimo Systems ◽  
Multiple Input Multiple Output ◽  
Wireless Channel ◽  
Single Input Single Output ◽  
Single Output ◽  
Minimum Mean Squared Error ◽  
Input Multiple Output

Detection in multiple-input-multiple-output (MIMO) wireless communication systems is a crucial procedure in receivers since the multiple access transmission schemes generate interference due to the simultaneous transmission along with the several antennas, unlike single-input-single-output (SISO) transmission schemes. Precoding is a technique in MIMO systems used to mitigate the effects of the channel over the received signal. Hence, it is possible to adjust continuously the transmitted information to reverse the effect of the wireless channel at the receiver side. In this work, linear sub-optimal detectors and precoders for massive MIMO (M-MIMO) systems are implemented, analyzed, and compared in terms of performance-complexity trade-off. It is also being considered numerical results in both channel scenarios: a) receiver and transmitter have perfect channel state information (CSI); b) complex channel coefficients are estimated with different levels of inaccuracy. Monte-Carlo simulations (MCS) reveal that linear zero-forcing (ZF) and minimum mean squared error (MMSE) massive MIMO detectors result in a certain robustness against multi-user interference when operating under low and medium system loading, L = K/M, thanks to the favourable propagation phenomenon arising in massive MIMO systems.

The Reverberating Chamber as a Line-of-Sight Wireless Channel Emulator

2008 ◽  
Vol 56 (6) ◽  
pp. 1825-1830 ◽  
Author(s):  
Antonio Sorrentino ◽  
Giuseppe Ferrara ◽  
Maurizio Migliaccio
Keyword(s):  
Wireless Channel ◽  
Line Of Sight ◽  
Channel Emulator

scholarly journals On the secrecy performance of transmit-receive diversity and spatial multiplexing systems

2019 ◽  
Vol 5 ◽  
pp. e186
Author(s):  
Kiattisak Maichalernnukul
Keyword(s):  
Physical Layer Security ◽  
Mimo Systems ◽  
Minimum Mean Square Error ◽  
Physical Layer ◽  
Wireless Channel ◽  
Spatial Multiplexing ◽  
Secrecy Outage Probability ◽  
Receive Diversity ◽  
The Impact ◽  
Multiplexing Systems

Emerging from the information-theoretic characterization of secrecy, physical-layer security exploits the physical properties of the wireless channel for security purpose. In recent years, a great deal of attention has been paid to investigating the physical-layer security issues in multiple-input multiple-output (MIMO) wireless communications. This paper analyzes the secrecy performance of transmit-receive diversity system and spatial multiplexing systems with zero-forcing equalization and minimum mean-square-error equalization. Specifically, exact and asymptotic closed-form expressions are derived for the secrecy outage probability of such MIMO systems in a Rayleigh fading environment, and the corresponding secrecy diversity orders and secrecy array gains are determined. Numerical results are presented to corroborate the analytical results and to examine the impact of various system parameters, including the numbers of antennas at the transmitter, the legitimate receiver, and the eavesdropper. These contributions bring about valuable insights into the physical-layer security in MIMO wireless systems.

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