365 research outputs found
Performance Analysis of Optimal Single Stream Beamforming in MIMO Dual-Hop AF Systems
This paper investigates the performance of optimal single stream beamforming
schemes in multiple-input multiple-output (MIMO) dual-hop amplify-and-forward
(AF) systems. Assuming channel state information is not available at the source
and relay, the optimal transmit and receive beamforming vectors are computed at
the destination, and the transmit beamforming vector is sent to the transmitter
via a dedicated feedback link. Then, a set of new closed-form expressions for
the statistical properties of the maximum eigenvalue of the resultant channel
is derived, i.e., the cumulative density function (cdf), probability density
function (pdf) and general moments, as well as the first order asymptotic
expansion and asymptotic large dimension approximations. These analytical
expressions are then applied to study three important performance metrics of
the system, i.e., outage probability, average symbol error rate and ergodic
capacity. In addition, more detailed treatments are provided for some important
special cases, e.g., when the number of antennas at one of the nodes is one or
large, simple and insightful expressions for the key parameters such as
diversity order and array gain of the system are derived. With the analytical
results, the joint impact of source, relay and destination antenna numbers on
the system performance is addressed, and the performance of optimal beamforming
schemes and orthogonal space-time block-coding (OSTBC) schemes are compared.
Results reveal that the number of antennas at the relay has a great impact on
how the numbers of antennas at the source and destination contribute to the
system performance, and optimal beamforming not only achieves the same maximum
diversity order as OSTBC, but also provides significant power gains over OSTBC.Comment: to appear in IEEE Journal on Selected Areas in Communications special
issue on Theories and Methods for Advanced Wireless Relay
Performance Analysis of Project-and-Forward Relaying in Mixed MIMO-Pinhole and Rayleigh Dual-Hop Channel
In this letter, we present an end-to-end performance analysis of dual-hop
project-and-forward relaying in a realistic scenario, where the source-relay
and the relay-destination links are experiencing MIMO-pinhole and Rayleigh
channel conditions, respectively. We derive the probability density function of
both the relay post-processing and the end-to-end signal-to-noise ratios, and
the obtained expressions are used to derive the outage probability of the
analyzed system as well as its end-to-end ergodic capacity in terms of
generalized functions. Applying then the residue theory to Mellin-Barnes
integrals, we infer the system asymptotic behavior for different channel
parameters. As the bivariate Meijer-G function is involved in the analysis, we
propose a new and fast MATLAB implementation enabling an automated definition
of the complex integration contour. Extensive Monte-Carlo simulations are
invoked to corroborate the analytical results.Comment: 4 pages, IEEE Communications Letters, 201
How to Understand LMMSE Transceiver Design for MIMO Systems From Quadratic Matrix Programming
In this paper, a unified linear minimum mean-square-error (LMMSE) transceiver
design framework is investigated, which is suitable for a wide range of
wireless systems. The unified design is based on an elegant and powerful
mathematical programming technology termed as quadratic matrix programming
(QMP). Based on QMP it can be observed that for different wireless systems,
there are certain common characteristics which can be exploited to design LMMSE
transceivers e.g., the quadratic forms. It is also discovered that evolving
from a point-to-point MIMO system to various advanced wireless systems such as
multi-cell coordinated systems, multi-user MIMO systems, MIMO cognitive radio
systems, amplify-and-forward MIMO relaying systems and so on, the quadratic
nature is always kept and the LMMSE transceiver designs can always be carried
out via iteratively solving a number of QMP problems. A comprehensive framework
on how to solve QMP problems is also given. The work presented in this paper is
likely to be the first shoot for the transceiver design for the future
ever-changing wireless systems.Comment: 31 pages, 4 figures, Accepted by IET Communication
Ergodic Capacity Analysis of Amplify-and-Forward MIMO Dual-Hop Systems
This paper presents an analytical characterization of the ergodic capacity of
amplify-and-forward (AF) MIMO dual-hop relay channels, assuming that the
channel state information is available at the destination terminal only. In
contrast to prior results, our expressions apply for arbitrary numbers of
antennas and arbitrary relay configurations. We derive an expression for the
exact ergodic capacity, simplified closed-form expressions for the high SNR
regime, and tight closed-form upper and lower bounds. These results are made
possible to employing recent tools from finite-dimensional random matrix theory
to derive new closed-form expressions for various statistical properties of the
equivalent AF MIMO dual-hop relay channel, such as the distribution of an
unordered eigenvalue and certain random determinant properties. Based on the
analytical capacity expressions, we investigate the impact of the system and
channel characteristics, such as the antenna configuration and the relay power
gain. We also demonstrate a number of interesting relationships between the
dual-hop AF MIMO relay channel and conventional point-to-point MIMO channels in
various asymptotic regimes.Comment: 40 pages, 9 figures, Submitted to to IEEE Transactions on Information
Theor
A virtual MIMO dual-hop architecture based on hybrid spatial modulation
International audienceIn this paper, we propose a novel Virtual Multiple-Input-Multiple-Output (VMIMO) architecture based on the concept of Spatial Modulation (SM). Using a dual-hop and Decode-and-Forward protocol, we form a distributed system, called Dual-Hop Hybrid SM (DH-HSM). DH-HSM conveys information from a Source Node (SN) to a Destination Node (DN) via multiple Relay Nodes (RNs). The spatial position of the RNs is exploited for transferring information in addition to, or even without, a conventional symbol. In order to increase the performance of our architecture, while keeping the complexity of the RNs and DN low, we employ linear precoding using Channel State Information (CSI) at the SN. In this way, we form a Receive-Spatial Modulation (R-SM) pattern from the SN to the RNs, which is able to employ a centralized coordinated or a distributed uncoordinated detection algorithm at the RNs. In addition, we focus on the SN and propose two regularized linear precoding methods that employ realistic Imperfect Channel State Information at the Transmitter. The power of each precoder is analyzed theoretically. Using the Bit Error Rate (BER) metric, we evaluate our architecture against the following benchmark systems: 1) single relay; 2) best relay selection; 3) distributed Space Time Block Coding (STBC) VMIMO scheme; and 4) the direct communication link. We show that DH-HSM is able to achieve significant Signal-to-Noise Ratio (SNR) gains, which can be as high as 10.5 dB for a very large scale system setup. In order to verify our simulation results, we provide an analytical framework for the evaluation of the Average Bit Error Probability (ABEP)
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