Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: UAV Relay-Assisted Emergency Communications in IoT Networks: Resource
  Allocation and Trajectory Optimization   Unmanned aerial vehicle (UAV) communication has emerged as a prominent
technology for emergency communications (e.g., natural disaster) in the
Internet of Things (IoT) networks to enhance the ability of disaster
prediction, damage assessment, and rescue operations promptly. A UAV can be
deployed as a flying base station (BS) to collect data from time-constrained
IoT devices and then transfer it to a ground gateway (GW). In general, the
latency constraint at IoT devices and UAV's limited storage capacity highly
hinder practical applications of UAV-assisted IoT networks. In this paper,
{full-duplex (FD) radio} is adopted at the UAV to overcome these challenges. In
addition, half-duplex (HD) scheme for UAV-based relaying is also considered to
provide a comparative study between two modes (viz., FD and HD). {Herein, a
device is considered to be successfully served iff its data is collected by the
UAV and conveyed to GW timely during flight time}. In this context, we aim to
maximize the number of served IoT devices by jointly optimizing bandwidth,
power allocation, and the UAV trajectory while satisfying each device's
requirement and the UAV's limited storage capacity. The formulated optimization
problem is troublesome to solve due to its non-convexity and combinatorial
nature. {Towards appealing applications, we first relax binary variables into
continuous ones and transform the original problem into a more computationally
tractable form.} By leveraging inner approximation framework, we derive newly
approximated functions for non-convex parts and then develop a simple yet
efficient iterative algorithm for its solutions. Next, we attempt to maximize
the total throughput subject to the number of served IoT devices. Finally,
numerical results show that the proposed algorithms significantly outperform
benchmark approaches in terms of the number of served IoT devices and system
throughput.

34
The categories of this paper are: chem-ph
32
The categories of this paper are: atom-ph
25
The categories of this paper are: patt-sol
37
The categories of this paper are: supr-con
18
The categories of this paper are: econ
10
The categories of this paper are: q-bio
30
The categories of this paper are: q-alg
12
The categories of this paper are: nucl-th
33
The categories of this paper are: plasm-ph
17
The categories of this paper are: q-fin
14
The categories of this paper are: math-ph
0
The categories of this paper are: hep-ph
31
The categories of this paper are: ao-sci
22
The categories of this paper are: chao-dyn
9
The categories of this paper are: nlin
15
The categories of this paper are: nucl-ex