2 research outputs found
Optimization of Wireless Relaying With Flexible UAV-Borne Reflecting Surfaces
This paper presents a theoretical framework to analyze the performance of
integrated unmanned aerial vehicle (UAV)-intelligent reflecting surface (IRS)
relaying system in which IRS provides an additional degree of freedom combined
with the flexible deployment of full-duplex UAV to enhance communication
between ground nodes. Our framework considers three different transmission
modes: {\bf (i)} UAV-only mode, {\bf (ii)} IRS-only mode, and {\bf (iii)}
integrated UAV-IRS mode to achieve spectral and energy-efficient relaying. For
the proposed modes, we provide exact and approximate expressions for the
end-to-end outage probability, ergodic capacity, and energy efficiency (EE) in
closed-form.
We use the derived expressions to optimize key system parameters such as the
UAV altitude and the number of elements on the IRS considering different modes.
We formulate the problems in the form of fractional programming (e.g. single
ratio, sum of multiple ratios or maximization-minimization of ratios) and
devise optimal algorithms using quadratic transformations. Furthermore, we
derive an analytic criterion to optimally select different transmission modes
to maximize ergodic capacity and EE for a given number of IRS elements.
Numerical results validate the derived expressions with Monte-Carlo simulations
and the proposed optimization algorithms with the solutions obtained through
exhaustive search. Insights are drawn related to the different communication
modes, optimal number of IRS elements, and optimal UAV height
Smart Soft-RAN for 5G: Dynamic Resource Management in CoMP-NOMA Based Systems
In this paper, we design a new smart software-defined radio access network
architecture which is flexible and traffic and density aware for the fifth
generation (5G) of cellular wireless networks and beyond. The proposed
architecture, based on network parameters such as density of users and system
traffic, performs five important tasks namely, dynamic radio resource
management (RRM), dynamic BS type selection, dynamic functionality splitting,
dynamic transmission technology selection, and dynamic framing. In this regard,
we first elaborate the structure of the proposed smart soft-RAN model and
explain the details of the proposed architecture and RRM algorithms. Next, as a
case study, based on the proposed architecture, we design a novel coordinated
multi point beamforming technique to enhance the throughput of a virtualized
software defined-based 5G network utilizing the combination of power domain
non-orthogonal multiple access and multiple-input single-output downlink
communication. In doing so, we formulate an optimization problem with the aim
of maximizing the total throughput subject to minimum required data rate of
each user and maximum transmit power constraint of each mobile virtual network
operator and each BS, and find jointly the non-orthogonal set, beamforming, and
subcarrier allocation. To solve the proposed optimization problem, based on the
network density, we design two centralized and semi-centralized algorithms.
Specifically, for the ultra-dense scenario, we use the centralized algorithm
while the semi-centralized one is used for the high and moderate density
scenarios. Numerical results illustrate the performance and signaling overhead
of the proposed algorithms, e.g., taking computational limitations into account
the number of supported users is increased by more than 60%.Comment: There are some issues about the wireless network virtualization and
CoMP-NOMA models in our paper. (The revised version of this paper can be
found in arxiv:2007.10013v1.