148 research outputs found
Delay Performance of MISO Wireless Communications
Ultra-reliable, low latency communications (URLLC) are currently attracting
significant attention due to the emergence of mission-critical applications and
device-centric communication. URLLC will entail a fundamental paradigm shift
from throughput-oriented system design towards holistic designs for guaranteed
and reliable end-to-end latency. A deep understanding of the delay performance
of wireless networks is essential for efficient URLLC systems. In this paper,
we investigate the network layer performance of multiple-input, single-output
(MISO) systems under statistical delay constraints. We provide closed-form
expressions for MISO diversity-oriented service process and derive
probabilistic delay bounds using tools from stochastic network calculus. In
particular, we analyze transmit beamforming with perfect and imperfect channel
knowledge and compare it with orthogonal space-time codes and antenna
selection. The effect of transmit power, number of antennas, and finite
blocklength channel coding on the delay distribution is also investigated. Our
higher layer performance results reveal key insights of MISO channels and
provide useful guidelines for the design of ultra-reliable communication
systems that can guarantee the stringent URLLC latency requirements.Comment: This work has been submitted to the IEEE for possible publication.
Copyright may be transferred without notice, after which this version may no
longer be accessibl
On secure system performance over SISO, MISO and MIMO-NOMA wireless networks equipped a multiple antenna based on TAS protocol
This study examined how to improve system performance by equipping multiple antennae at a base station (BS) and all terminal users/mobile devices instead of a single antenna as in previous studies. Experimental investigations based on three NOMA down-link models involved (1) a single-input-single-output (SISO) scenario in which a single antenna was equipped at a BS and for all users, (2) a multi-input-single-output (MISO) scenario in which multiple transmitter antennae were equipped at a BS and a single receiver antenna for all users and (3) a multi-input-multi-output (MIMO) scenario in which multiple transmitter antennae were equipped at a BS and multiple receiver antenna for all users. This study investigated and compared the outage probability (OP) and system throughput assuming all users were over Rayleigh fading channels. The individual scenarios also each had an eavesdropper. Secure system performance of the individual scenarios was therefore also investigated. In order to detect data from superimposed signals, successive interference cancellation (SIC) was deployed for users, taking into account perfect, imperfect and fully imperfect SICs. The results of analysis of users in these three scenarios were obtained in an approximate closed form by using the Gaussian-Chebyshev quadrature method. However, the clearly and accurately presented results obtained using Monte Carlo simulations prove and verify that the MIMO-NOMA scenario equipped with multiple antennae significantly improved system performance.Web of Science20201art. no. 1
Secrecy Enhancement of Multiuser MISO Networks Using OSTBC and Artificial Noise
In this paper, we propose a novel physical layer
strategy to improve the secrecy performance of multiuser
multiple-input single-output networks. In this strategy, orthogonal
space-time block code (OSTBC) is employed at an AAantenna
base station (BS) and artificial noise (AN) is employed
at an AJ-antenna cooperative relay to enhance the security
level of the network. Moreover, two opportunistic scheduling
schemes, namely, selection combining (SC) and scan-and-wait
combining (SWC), are leveraged to select one legitimate user
for data transmission. To evaluate the secrecy performance of
the proposed OSTBC-SC-AN and OSTBC-SWC-AN schemes, we
derive new exact closed-form expressions for the secrecy outage
probability and the effective secrecy throughput. Using numerical
results, we show that the OSTBC-SWC-AN scheme outperforms
the OSTBC-SC-AN scheme when the switching threshold is
carefully chosen. We also show that increasing AA brings down
the secrecy performance in the presence of a high switching
threshold.ARC Discovery Projects Grant DP150103905
Short-Packet Communications for MIMO NOMA Systems over Nakagami-m Fading: BLER and Minimum Blocklength Analysis
Recently, ultra-reliable and low-latency communications (URLLC) using
short-packets has been proposed to fulfill the stringent requirements regarding
reliability and latency of emerging applications in 5G and beyond networks. In
addition, multiple-input multiple-output non-orthogonal multiple access (MIMO
NOMA) is a potential candidate to improve the spectral efficiency, reliability,
latency, and connectivity of wireless systems. In this paper, we investigate
short-packet communications (SPC) in a multiuser downlink MIMO NOMA system over
Nakagami-m fading, and propose two antenna-user selection methods considering
two clusters of users having different priority levels. In contrast to the
widely-used long data-packet assumption, the SPC analysis requires the redesign
of the communication protocols and novel performance metrics. Given this
context, we analyze the SPC performance of MIMO NOMA systems using the average
block error rate (BLER) and minimum blocklength, instead of the conventional
metrics such as ergodic capacity and outage capacity. More specifically, to
characterize the system performance regarding SPC, asymptotic (in the high
signal-to-noise ratio regime) and approximate closed-form expressions of the
average BLER at the users are derived. Based on the asymptotic behavior of the
average BLER, an analysis of the diversity order, minimum blocklength, and
optimal power allocation is carried out. The achieved results show that MIMO
NOMA can serve multiple users simultaneously using a smaller blocklength
compared with MIMO OMA, thus demonstrating the benefits of MIMO NOMA for SPC in
minimizing the transmission latency. Furthermore, our results indicate that the
proposed methods not only improve the BLER performance but also guarantee full
diversity gains for the respective users.Comment: 12 pages, 8 figures. This paper has been submitted to an IEEE journal
for possible publicatio
- …