1,975 research outputs found
Asymptotic Mutual Information Statistics of Separately-Correlated Rician Fading MIMO Channels
Precise characterization of the mutual information of MIMO systems is
required to assess the throughput of wireless communication channels in the
presence of Rician fading and spatial correlation. Here, we present an
asymptotic approach allowing to approximate the distribution of the mutual
information as a Gaussian distribution in order to provide both the average
achievable rate and the outage probability. More precisely, the mean and
variance of the mutual information of the separatelycorrelated Rician fading
MIMO channel are derived when the number of transmit and receive antennas grows
asymptotically large and their ratio approaches a finite constant. The
derivation is based on the replica method, an asymptotic technique widely used
in theoretical physics and, more recently, in the performance analysis of
communication (CDMA and MIMO) systems. The replica method allows to analyze
very difficult system cases in a comparatively simple way though some authors
pointed out that its assumptions are not always rigorous. Being aware of this,
we underline the key assumptions made in this setting, quite similar to the
assumptions made in the technical literature using the replica method in their
asymptotic analyses. As far as concerns the convergence of the mutual
information to the Gaussian distribution, it is shown that it holds under some
mild technical conditions, which are tantamount to assuming that the spatial
correlation structure has no asymptotically dominant eigenmodes. The accuracy
of the asymptotic approach is assessed by providing a sizeable number of
numerical results. It is shown that the approximation is very accurate in a
wide variety of system settings even when the number of transmit and receive
antennas is as small as a few units.Comment: - submitted to the IEEE Transactions on Information Theory on Nov.
19, 2006 - revised and submitted to the IEEE Transactions on Information
Theory on Dec. 19, 200
Achievable Rate of Rician Large-Scale MIMO Channels with Transceiver Hardware Impairments
Transceiver hardware impairments (e.g., phase noise,
in-phase/quadrature-phase (I/Q) imbalance, amplifier non-linearities, and
quantization errors) have obvious degradation effects on the performance of
wireless communications. While prior works have improved our knowledge on the
influence of hardware impairments of single-user multiple-input multiple-output
(MIMO) systems over Rayleigh fading channels, an analysis encompassing the
Rician fading channel is not yet available. In this paper, we pursue a detailed
analysis of regular and large-scale (LS) MIMO systems over Rician fading
channels by deriving new, closed-form expressions for the achievable rate to
provide several important insights for practical system design. More
specifically, for regular MIMO systems with hardware impairments, there is
always a finite achievable rate ceiling, which is irrespective of the transmit
power and fading conditions. For LS-MIMO systems, it is interesting to find
that the achievable rate loss depends on the Rician -factor, which reveals
that the favorable propagation in LS-MIMO systems can remove the influence of
hardware impairments. However, we show that the non-ideal LS-MIMO system can
still achieve high spectral efficiency due to its huge degrees of freedom.Comment: 7 pages, 1 table, 3 figures, accepted to appear in IEEE Transactions
on Vehicular Technolog
Analysis of Coverage Region for MIMO Relay Network with Multiple Cooperative DF-Relays
We study and analyze coverage region in MIMO communication systems for a
multiple-relay network with decode-and-forward (DF) strategy at the relays.
Assuming that there is a line-of-sight (LOS) propagation environment for
source-relay channels and channel state information is available at receivers
(CSIR), we consider the objective of maximizing coverage region for a given
transmission rate and show numerically the significant effect of propagation
environment on capacity bounds, optimal relay location and coverage region.
Also, we study the situation in which two adjacent relays cooperate in
transmission signals to the destination and show analytically that the coverage
region is extended compared to noncooperative scenario.Comment: Accepted for publication in International Symposium on Wireless
Communication Systems (ISWCS) 201
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