11 research outputs found
Laplace Functional Ordering of Point Processes in Large-scale Wireless Networks
Stochastic orders on point processes are partial orders which capture notions
like being larger or more variable. Laplace functional ordering of point
processes is a useful stochastic order for comparing spatial deployments of
wireless networks. It is shown that the ordering of point processes is
preserved under independent operations such as marking, thinning, clustering,
superposition, and random translation. Laplace functional ordering can be used
to establish comparisons of several performance metrics such as coverage
probability, achievable rate, and resource allocation even when closed form
expressions of such metrics are unavailable. Applications in several network
scenarios are also provided where tradeoffs between coverage and interference
as well as fairness and peakyness are studied. Monte-Carlo simulations are used
to supplement our analytical results.Comment: 30 pages, 5 figures, Submitted to Hindawi Wireless Communications and
Mobile Computin
Downlink Coverage and Rate Analysis of Low Earth Orbit Satellite Constellations Using Stochastic Geometry
As low Earth orbit (LEO) satellite communication systems are gaining
increasing popularity, new theoretical methodologies are required to
investigate such networks' performance at large. This is because deterministic
and location-based models that have previously been applied to analyze
satellite systems are typically restricted to support simulations only. In this
paper, we derive analytical expressions for the downlink coverage probability
and average data rate of generic LEO networks, regardless of the actual
satellites' locality and their service area geometry. Our solution stems from
stochastic geometry, which abstracts the generic networks into uniform binomial
point processes. Applying the proposed model, we then study the performance of
the networks as a function of key constellation design parameters. Finally, to
fit the theoretical modeling more precisely to real deterministic
constellations, we introduce the effective number of satellites as a parameter
to compensate for the practical uneven distribution of satellites on different
latitudes. In addition to deriving exact network performance metrics, the study
reveals several guidelines for selecting the design parameters for future
massive LEO constellations, e.g., the number of frequency channels and
altitude.Comment: Accepted for publication in the IEEE Transactions on Communications
in April 202
Stochastic Geometry Modeling and Analysis of Single- and Multi-Cluster Wireless Networks
This paper develops a stochastic geometry-based approach for the modeling and
analysis of single- and multi-cluster wireless networks. We first define finite
homogeneous Poisson point processes to model the number and locations of the
transmitters in a confined region as a single-cluster wireless network. We
study the coverage probability for a reference receiver for two strategies;
closest-selection, where the receiver is served by the closest transmitter
among all transmitters, and uniform-selection, where the serving transmitter is
selected randomly with uniform distribution. Second, using Matern cluster
processes, we extend our model and analysis to multi-cluster wireless networks.
Here, the receivers are modeled in two types, namely, closed- and open-access.
Closed-access receivers are distributed around the cluster centers of the
transmitters according to a symmetric normal distribution and can be served
only by the transmitters of their corresponding clusters. Open-access
receivers, on the other hand, are placed independently of the transmitters and
can be served by all transmitters. In all cases, the link distance distribution
and the Laplace transform (LT) of the interference are derived. We also derive
closed-form lower bounds on the LT of the interference for single-cluster
wireless networks. The impact of different parameters on the performance is
also investigated
Stochastic Geometry Modeling and Analysis of Finite Millimeter Wave Wireless Networks
This paper develops a stochastic geometry-based approach for the modeling and
analysis of finite millimeter wave (mmWave) wireless networks where a random
number of transmitters and receivers are randomly located inside a finite
region. We consider a selection strategy to serve a reference receiver by the
transmitter providing the maximum average received power among all
transmitters. Considering the unique features of mmWave communications such as
directional transmit and receive beamforming and having different channels for
line-of-sight (LOS) and non-line-of-sight (NLOS) links according to the
blockage process, we study the coverage probability and the ergodic rate for
the reference receiver that can be located everywhere inside the network
region. As key steps for the analyses, the distribution of the distance from
the reference receiver to its serving LOS or NLOS transmitter and LOS and NLOS
association probabilities are derived. We also derive the Laplace transform of
the interferences from LOS and NLOS transmitters. Finally, we propose upper and
lower bounds on the coverage probability that can be evaluated easier than the
exact results, and investigate the impact of different parameters including the
receiver location, the beamwidth, and the blockage process exponent on the
system performance
Optimal Deployment of Tethered Drones for Maximum Cellular Coverage in User Clusters
Unmanned aerial vehicle (UAV) assisted cellular communication is gaining
significant interest recently. Although it offers several advantages over
terrestrial communication, UAV communication suffers from two main
shortcomings. The typical untethered UAV (uUAV) has a limited battery power
supply and therefore limited flying time, and it needs an extra wireless
backhaul link to connect users to the core network. In this paper, we propose
the utilization of the tethered UAV (tUAV) to assist the cellular network,
where the tether provides power supply and connects the tUAV to the core
network through high capacity link. The tUAV however has a limited mobility due
to the limited tether length. A stochastic geometry-based analysis is provided
for the coverage probability of an UAV-assisted cellular network where the
mobile users located within a circular hot-spot. For that setup, we analyze and
compare two scenarios: (i) utilizing uUAV and (ii) utilizing tUAV, for
offloading the terrestrial base station (TBS). We capture the aforementioned
limitations of each of the uUAV and the tUAV in our analysis. A novel user
association analysis is provided given the TBS and the UAV locations. Next, we
study the optimal locations of the uUAV and the tUAV to maximize the coverage
probability. Multiple useful insights are revealed. For instance, numerical
results show that tUAVs outperform uUAVs when the tether length is above 75 m,
given that the uUAV is available for 80% of the time due to its battery
limitations.Comment: Accepted at the IEEE Transaction on Wireless Communication
Outage Performance of Uplink Rate Splitting Multiple Access with Randomly Deployed Users
With the rapid proliferation of smart devices in wireless networks, more
powerful technologies are expected to fulfill the network requirements of high
throughput, massive connectivity, and diversify quality of service. To this
end, rate splitting multiple access (RSMA) is proposed as a promising solution
to improve spectral efficiency and provide better fairness for the
next-generation mobile networks. In this paper, the outage performance of
uplink RSMA transmission with randomly deployed users is investigated, taking
both user scheduling schemes and power allocation strategies into
consideration. Specifically, the greedy user scheduling (GUS) and cumulative
distribution function (CDF) based user scheduling (CUS) schemes are considered,
which could maximize the rate performance and guarantee scheduling fairness,
respectively. Meanwhile, we re-investigate cognitive power allocation (CPA)
strategy, and propose a new rate fairness-oriented power allocation (FPA)
strategy to enhance the scheduled users' rate fairness. By employing order
statistics and stochastic geometry, an analytical expression of the outage
probability for each scheduling scheme combining power allocation is derived to
characterize the performance. To get more insights, the achieved diversity
order of each scheme is also derived. Theoretical results demonstrate that both
GUS and CUS schemes applying CPA or FPA strategy can achieve full diversity
orders, and the application of CPA strategy in RSMA can effectively eliminate
the secondary user's diversity order constraint from the primary user.
Simulation results corroborate the accuracy of the analytical expressions, and
show that the proposed FPA strategy can achieve excellent rate fairness
performance in high signal-to-noise ratio region.Comment: 38 pages,8 figure
Optimizing the number of fog nodes for finite fog radio access networks under multi-slope path loss model
Fog Radio Access Network (F-RAN) is a promising technology to address the bandwidth bottlenecks and network latency problems, by providing cloud-like services to the end nodes (ENs) at the edge of the network. The network latency can further be decreased by minimizing the transmission delay, which can be achieved by optimizing the number of Fog Nodes (FNs). In this context, we propose a stochastic geometry model to optimize the number of FNs in a finite F-RAN by exploiting the multi-slope path loss model (MS-PLM), which can more precisely characterize the path loss dependency on the propagation environment. The proposed approach shows that the optimum probability of being a FN is determined by the real root of a polynomial equation of a degree determined by the far-field path loss exponent (PLE) of the MS-PLM. The results analyze the impact of the path loss parameters and the number of deployed nodes on the optimum number of FNs. The results show that the optimum number of FNs is less than 7% of the total number of deployed nodes for all the considered scenarios. It also shows that optimizing the number of FNs achieves a significant reduction in the average transmission delay over the unoptimized scenarios