81 research outputs found
From Multi-Keyholes to Measure of Correlation and Power Imbalance in MIMO Channels: Outage Capacity Analysis
An information-theoretic analysis of a multi-keyhole channel, which includes
a number of statistically independent keyholes with possibly different
correlation matrices, is given. When the number of keyholes or/and the number
of Tx/Rx antennas is large, there is an equivalent Rayleigh-fading channel such
that the outage capacities of both channels are asymptotically equal. In the
case of a large number of antennas and for a broad class of fading
distributions, the instantaneous capacity is shown to be asymptotically
Gaussian in distribution, and compact, closed-form expressions for the mean and
variance are given. Motivated by the asymptotic analysis, a simple,
full-ordering scalar measure of spatial correlation and power imbalance in MIMO
channels is introduced, which quantifies the negative impact of these two
factors on the outage capacity in a simple and well-tractable way. It does not
require the eigenvalue decomposition, and has the full-ordering property. The
size-asymptotic results are used to prove Telatar's conjecture for
semi-correlated multi-keyhole and Rayleigh channels. Since the keyhole channel
model approximates well the relay channel in the amplify-and-forward mode in
certain scenarios, these results also apply to the latterComment: accepted by IEEE IT Trans., 201
Rank-Deficiency in Indoor MIMO
This paper points out in an analytical way that rankdeficiency in indoor MIMO is typically due to the small size of scattering windows in the NLOS propagation path between the transmitter and the receiver
Reconfigurable intelligent surface (RIS): Eigenvalue Decomposition-Based Separate Channel Estimation
Reconfigurable intelligent surface (RIS) has recently drawn significant
attention in wireless communication technologies. However, identifying,
modeling, and estimating the RIS channel in multiple-input multiple-output
(MIMO) systems are considered challenging in recent studies. In this paper, a
disassembled channel estimation framework for the RIS-MIMO system is proposed
based on the eigenvalue decomposition (EVD) concept to separate the cascaded
channel links and estimate each link separately. This estimation is based on
modeling the RIS-MIMO channel as a keyhole MIMO system model. Numerical results
show that the proposed estimation method has a low estimation time overhead
while providing less estimation error.Comment: Published in: 2021 IEEE 32nd Annual International Symposium on
Personal, Indoor and Mobile Radio Communications (PIMRC
MIMO Channel Modeling: A Review
Abstract: Channel modeling plays an important role in understanding the behavior and designing of communication systems for different environments. In this paper, we make a brief review of the different channel modeling techniques used to model a multiple-input-multiple-output (MIMO) wireless channel
Ergodic Capacity of Doubly Selective Rayleigh Fading MIMO Channels
The ergodic capacity is investigated for doubly selective (frequency selective and time varying) MIMO Rayleigh fading channels. A closed form formula is derived that quantifies the effect of the ISI fading on the ergodic capacity into an ISI degradation factor. It is discovered that, in general frequency selective MIMO channels, the inter-tap correlations of the ISI fading will reduce the ergodic capacity comparing to the frequency flat fading channel. Only in the special case when the ISI fading does not have inter-tap correlations will the ergodic capacity be the same as that of the frequency flat channel. This new formula is mathematically proved and experimentally verified via Monte-Carlo simulations
Asymptotic Analysis of Double-Scattering Channels
We consider a multiple-input multiple-output (MIMO) multiple access channel
(MAC), where the channel between each transmitter and the receiver is modeled
by the doubly-scattering channel model. Based on novel techniques from random
matrix theory, we derive deterministic approximations of the mutual
information, the signal-to-noise-plus-interference-ratio (SINR) at the output
of the minimum-mean-square-error (MMSE) detector and the sum-rate with MMSE
detection which are almost surely tight in the large system limit. Moreover, we
derive the asymptotically optimal transmit covariance matrices. Our simulation
results show that the asymptotic analysis provides very close approximations
for realistic system dimensions.Comment: 5 pages, 2 figures, submitted to the Annual Asilomar Conference on
Signals, Systems, and Computers, Pacific Grove, CA, USA, 201
- …