80 research outputs found
A High-Diversity Transceiver Design for MISO Broadcast Channels
In this paper, the outage behavior and diversity order of the mixture
transceiver architecture for multiple-input single-output broadcast channels
are analyzed. The mixture scheme groups users with closely-aligned channels and
applies superposition coding and successive interference cancellation decoding
to each group composed of users with closely-aligned channels, while applying
zero-forcing beamforming across semi-orthogonal user groups. In order to enable
such analysis, closed-form lower bounds on the achievable rates of a general
multiple-input single-output broadcast channel with superposition coding and
successive interference cancellation are newly derived. By employing
channel-adaptive user grouping and proper power allocation, which ensures that
the channel subspaces of user groups have angle larger than a certain
threshold, it is shown that the mixture transceiver architecture achieves full
diversity order in multiple-input single-output broadcast channels and
opportunistically increases the multiplexing gain while achieving full
diversity order. Furthermore, the achieved full diversity order is the same as
that of the single-user maximum ratio transmit beamforming. Hence, the mixture
scheme can provide reliable communication under channel fading for
ultra-reliable low latency communication. Numerical results validate our
analysis and show the outage superiority of the mixture scheme over
conventional transceiver designs for multiple-input single-output broadcast
channels.Comment: The inner region is evaluated. The single-group SIC performance is
evaluate
Optimal and Suboptimal Detection of Gaussian Signals in Noise: Asymptotic Relative Efficiency
The performance of Bayesian detection of Gaussian signals using noisy
observations is investigated via the error exponent for the average error
probability. Under unknown signal correlation structure or limited processing
capability it is reasonable to use the simple quadratic detector that is
optimal in the case of an independent and identically distributed (i.i.d.)
signal. Using the large deviations principle, the performance of this detector
(which is suboptimal for non-i.i.d. signals) is compared with that of the
optimal detector for correlated signals via the asymptotic relative efficiency
defined as the ratio between sample sizes of two detectors required for the
same performance in the large-sample-size regime. The effects of SNR on the ARE
are investigated. It is shown that the asymptotic efficiency of the simple
quadratic detector relative to the optimal detector converges to one as the SNR
increases without bound for any bounded spectrum, and that the simple quadratic
detector performs as well as the optimal detector for a wide range of the
correlation values at high SNR.Comment: To appear in the Proceedings of the SPIE Conference on Advanced
Signal Processing Algorithms, Architectures and Implementations XV, San
Diego, CA, Jul. 1 - Aug. 4, 200
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