178 research outputs found
Hardware Impairments Aware Transceiver Design for Bidirectional Full-Duplex MIMO OFDM Systems
In this paper we address the linear precoding and decoding design problem for
a bidirectional orthogonal frequencydivision multiplexing (OFDM) communication
system, between two multiple-input multiple-output (MIMO) full-duplex (FD)
nodes. The effects of hardware distortion as well as the channel state
information error are taken into account. In the first step, we transform the
available time-domain characterization of the hardware distortions for FD MIMO
transceivers to the frequency domain, via a linear Fourier transformation. As a
result, the explicit impact of hardware inaccuracies on the residual
selfinterference (RSI) and inter-carrier leakage (ICL) is formulated in
relation to the intended transmit/received signals. Afterwards, linear
precoding and decoding designs are proposed to enhance the system performance
following the minimum-mean-squarederror (MMSE) and sum rate maximization
strategies, assuming the availability of perfect or erroneous CSI. The proposed
designs are based on the application of alternating optimization over the
system parameters, leading to a necessary convergence. Numerical results
indicate that the application of a distortionaware design is essential for a
system with a high hardware distortion, or for a system with a low thermal
noise variance.Comment: Submitted to IEEE for publicatio
Random Access Protocols for Cell-Free Wireless Network Exploiting Statistical Behavior of THz Signal Propagation
The current body of research on terahertz (THz) wireless communications
predominantly focuses on its application for single-user backhaul/fronthaul
connectivity at sub-THz frequencies. First, we develop a generalized
statistical model for signal propagation at THz frequencies encompassing
physical layer impairments, including random path-loss with Gamma distribution
for the molecular absorption coefficient, short-term fading characterized by
the --- distribution, antenna misalignment errors,
and transceiver hardware impairments. Next, we propose random access protocols
for a cell-free wireless network, ensuring successful transmission for multiple
users with limited delay and energy loss, exploiting the combined effect of
random atmospheric absorption, non-linearity of fading, hardware impairments,
and antenna misalignment errors. We consider two schemes: a fixed transmission
probability (FTP) scheme where the transmission probability (TP) of each user
is updated at the beginning of the data transmission and an adaptive
transmission probability (ATP) scheme where the TP is updated with each
successful reception of the data. We analyze the performance of both protocols
using delay, energy consumption, and outage probability with scaling laws for
the transmission of a data frame consisting of a single packet from users at a
predefined quality of service (QoS).Comment: This work has been submitted to IEEE for possible publcation. arXiv
admin note: substantial text overlap with arXiv:2310.1861
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