317 research outputs found
Performance Analysis of Energy-Detection-Based Massive SIMO
Recently, communications systems that are both energy efficient and reliable
are under investigation. In this paper, we concentrate on an
energy-detection-based transmission scheme where a communication scenario
between a transmitter with one antenna and a receiver with significantly many
antennas is considered. We assume that the receiver initially calculates the
average energy across all antennas, and then decodes the transmitted data by
exploiting the average energy level. Then, we calculate the average symbol
error probability by means of a maximum a-posteriori probability detector at
the receiver. Following that, we provide the optimal decision regions.
Furthermore, we develop an iterative algorithm that reaches the optimal
constellation diagram under a given average transmit power constraint. Through
numerical analysis, we explore the system performance
Design and Performance Analysis of Non-Coherent Detection Systems with Massive Receiver Arrays
Harvesting the gain of a large number of antennas in a mmWave band has mainly
been relying on the costly operation of channel state information (CSI)
acquisition and cumbersome phase shifters. Recent works have started to
investigate the possibility to use receivers based on energy detection (ED),
where a single data stream is decoded based on the channel and noise energy.
The asymptotic features of the massive receiver array lead to a system where
the impact of the noise becomes predictable due to a noise hardening effect.
This in effect extends the communication range compared to the receiver with a
small number of antennas, as the latter is limited by the unpredictability of
the additive noise. When the channel has a large number of spatial degrees of
freedom, the system becomes robust to imperfect channel knowledge due to
channel hardening. We propose two detection methods based on the instantaneous
and average channel energy, respectively. Meanwhile, we design the detection
thresholds based on the asymptotic properties of the received energy.
Differently from existing works, we analyze the scaling law behavior of the
symbol-error-rate (SER). When the instantaneous channel energy is known, the
performance of ED approaches that of the coherent detection in high SNR
scenarios. When the receiver relies on the average channel energy, our
performance analysis is based on the exact SER, rather than an approximation.
It is shown that the logarithm of SER decreases linearly as a function of the
number of antennas. Additionally, a saturation appears at high SNR for PAM
constellations of order larger than two, due to the uncertainty on the channel
energy. Simulation results show that ED, with a much lower complexity, achieves
promising performance both in Rayleigh fading channels and in sparse channels
Noncoherent Space-Time Coding: An Algebraic Perspective
Cataloged from PDF version of article.The design of space–time signals for noncoherent
block-fading channels where the channel state information is
not known a priori at the transmitter and the receiver is considered.
In particular, a new algebraic formulation for the diversity
advantage design criterion is developed. The new criterion encompasses,
as a special case, the well-known diversity advantage
for unitary space–time signals and, more importantly, applies to
arbitrary signaling schemes and arbitrary channel distributions.
This criterion is used to establish the optimal diversity-versus-rate
tradeoff for training based schemes in block-fading channels.
Our results are then specialized to the class of affine space–time
signals which allows for a low complexity decoder. Within this
class, space–time constellations based on the threaded algebraic
space–time (TAST) architecture are considered. These constellations
achieve the optimal diversity-versus-rate tradeoff over
noncoherent block-fading channels and outperform previously
proposed codes in the considered scenarios as demonstrated by
the numerical results. Using the analytical and numerical results
developed in this paper, nonunitary space–time codes are argued
to offer certain advantages in block-fading channels where the appropriate
use of coherent space–time codes is shown to offer a very
efficient solution to the noncoherent space–time communication
paradigm
Dispensing with Channel Estimation…
In this article, we investigate the feasibility of noncoherent detection schemes in wireless communication systems as a low-complexity alternative to the family of coherent schemes. The noncoherent schemes require no channel knowledge at the receiver for the detection of the received signal, while the coherent schemes require channel inherently complex estimation, which implies that pilot symbols have to be transmitted resulting in a wastage of the available bandwidth as well as the transmission power
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