64 research outputs found
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Radio Resource Management for Satellite UMTS. Dynamic scheduling algorithm for a UMTS-compatible satellite network.
The third generation of mobile communication systems introduce
interactive Multicast and Unicast multimedia services at a fast data rate of
up to 2 Mbps and is expected to complete the globalization of the mobile
telecommunication systems. The implementation of these services on
satellite systems, particularly for broadcast and multicast applications to
complement terrestrial services is ideal since satellite systems are capable
of providing global coverage in areas not served by terrestrial
telecommunication services. However, the main bottleneck of such
systems is the scarcity of radio resources for supporting multimedia
applications which has resulted in the rapid growth in research efforts for
deriving efficient radio resource management techniques. This issue is
addressed in this thesis, where the main emphasis is to design a dynamic
scheduling framework and algorithm that can improve the overall
performance of the radio resource management strategy of a UMTS
compatible satellite network, taking into account the unique characteristics
of wireless channel conditions.
This thesis will initially be focused on the design of the network and
functional architecture of a UMTS -compatible satellite network. Based on
this architecture, an effective scheduling framework is designed, which
can provide different types of resource assigning strategies. A functional
model of scheduler is defined to describe the behaviours and interactions
between different functional entities.
An OPNET simulation model with a complete network protocol stack is
developed to validate the performance of the scheduling algorithms
implemented in the satellite network. Different types of traffic are
considered for the OPNET simulation, such as the Poisson Process, ONOFF
Source and Self Similar Process, so that the performance of
scheduling algorithm can be analyzed for different types of services.
A novel scheduling algorithm is proposed to optimise the channel
utilisation by considering the characteristics of the wireless channel, which
are bursty and location dependent. In order to overcome the channel
errors, different code rates are applied for the user under different channel
conditions. The proposed scheduling algorithm is designed to give higher
priority to users with higher code rate, so that the throughput of network is
optimized and at the same time, maintaining the end users¿ service level
agreements. The fairness of the proposed scheduling algorithm is
validated using OPNET simulation. The simulation results show that the
algorithm can fairly allocate resource to different connections not only
among different service classes but also within the same service class
depending on their QoS attributes.Inmarsat Global Ltd. BGAN and the European Space Agency (ESA
Revolutionizing Future Connectivity: A Contemporary Survey on AI-empowered Satellite-based Non-Terrestrial Networks in 6G
Non-Terrestrial Networks (NTN) are expected to be a critical component of 6th
Generation (6G) networks, providing ubiquitous, continuous, and scalable
services. Satellites emerge as the primary enabler for NTN, leveraging their
extensive coverage, stable orbits, scalability, and adherence to international
regulations. However, satellite-based NTN presents unique challenges, including
long propagation delay, high Doppler shift, frequent handovers, spectrum
sharing complexities, and intricate beam and resource allocation, among others.
The integration of NTNs into existing terrestrial networks in 6G introduces a
range of novel challenges, including task offloading, network routing, network
slicing, and many more. To tackle all these obstacles, this paper proposes
Artificial Intelligence (AI) as a promising solution, harnessing its ability to
capture intricate correlations among diverse network parameters. We begin by
providing a comprehensive background on NTN and AI, highlighting the potential
of AI techniques in addressing various NTN challenges. Next, we present an
overview of existing works, emphasizing AI as an enabling tool for
satellite-based NTN, and explore potential research directions. Furthermore, we
discuss ongoing research efforts that aim to enable AI in satellite-based NTN
through software-defined implementations, while also discussing the associated
challenges. Finally, we conclude by providing insights and recommendations for
enabling AI-driven satellite-based NTN in future 6G networks.Comment: 40 pages, 19 Figure, 10 Tables, Surve
Telecommunications Networks
This book guides readers through the basics of rapidly emerging networks to more advanced concepts and future expectations of Telecommunications Networks. It identifies and examines the most pressing research issues in Telecommunications and it contains chapters written by leading researchers, academics and industry professionals. Telecommunications Networks - Current Status and Future Trends covers surveys of recent publications that investigate key areas of interest such as: IMS, eTOM, 3G/4G, optimization problems, modeling, simulation, quality of service, etc. This book, that is suitable for both PhD and master students, is organized into six sections: New Generation Networks, Quality of Services, Sensor Networks, Telecommunications, Traffic Engineering and Routing
Resource Allocation in Relay-based Satellite and Wireless Communication Networks
A two-level bandwidth allocation scheme is proposed for a slotted Time-Division Multiple Access high data rate relay satellite communication link to provide efficient and fair channel utilization. The long-term allocation is implemented to provide per-flow/per-user Quality-of-Service guarantees and shape the average behavior. The time-varying short-term allocation is determined by solving an optimal timeslot scheduling problem based on the requests and other parameters. Through extensive simulations, the performance of a suitable MAC protocol with two-level bandwidth allocation is analyzed and compared with that of the existing static fixed-assignment scheme in terms of end-to-end delay and successful throughput. It is also shown that pseudo-proportional fairness is achieved for our hybrid protocol.
We study rate control systems with heterogeneous time-varying propagation delays, based on analytic fluid flow models composed of first-order delay-differential equations. Both single-flow and multi-flow system models are analyzed, with special attention paid to the Mitra-Seery algorithm. The stationary solutions are investigated. For the fluctuating solutions, their dynamic behavior is analyzed in detail, analytically and numerically, in terms of amplitude, transient behavior, fairness and adaptability, etc.. Especially the effects of heterogeneous time-varying delays are investigated. It is shown that with proper parameter design the system can achieve stable behavior with close to pointwise proportional fairness among flows.
Finally we investigate the resource allocation in 802.16j multi-hop relay systems with rate fairness constraints for two mutually exclusive options: transparent and non-transparent relay systems (T-RS and NT-RS). Single-Input Single-Output and Multi-Input Multi-Output antenna systems are considered in the links between the Base Station (BS) and Relay Stations (RS). 1 and 3 RSs per sector are considered. The Mobile Station (MS) association rule, which determines the access station (BS or RS) for each MS, is also studied. Two rules: Highest MCS scheme with the highest modulation and coding rate, and Highest (Mod) ESE scheme with the highest (modified) effective spectrum efficiency, are studied along with the optimal rule that maximizes system capacity with rate fairness constraints. Our simulation results show that the highest capacity is always achieved by NT-RS with 3 RSs per sector in distributed scheduling mode, and that the Highest (Mod) ESE scheme performs closely to the optimal rule in terms of system capacity
Applications of Repeated Games in Wireless Networks: A Survey
A repeated game is an effective tool to model interactions and conflicts for
players aiming to achieve their objectives in a long-term basis. Contrary to
static noncooperative games that model an interaction among players in only one
period, in repeated games, interactions of players repeat for multiple periods;
and thus the players become aware of other players' past behaviors and their
future benefits, and will adapt their behavior accordingly. In wireless
networks, conflicts among wireless nodes can lead to selfish behaviors,
resulting in poor network performances and detrimental individual payoffs. In
this paper, we survey the applications of repeated games in different wireless
networks. The main goal is to demonstrate the use of repeated games to
encourage wireless nodes to cooperate, thereby improving network performances
and avoiding network disruption due to selfish behaviors. Furthermore, various
problems in wireless networks and variations of repeated game models together
with the corresponding solutions are discussed in this survey. Finally, we
outline some open issues and future research directions.Comment: 32 pages, 15 figures, 5 tables, 168 reference
A Vision and Framework for the High Altitude Platform Station (HAPS) Networks of the Future
A High Altitude Platform Station (HAPS) is a network node that operates in
the stratosphere at an of altitude around 20 km and is instrumental for
providing communication services. Precipitated by technological innovations in
the areas of autonomous avionics, array antennas, solar panel efficiency
levels, and battery energy densities, and fueled by flourishing industry
ecosystems, the HAPS has emerged as an indispensable component of
next-generations of wireless networks. In this article, we provide a vision and
framework for the HAPS networks of the future supported by a comprehensive and
state-of-the-art literature review. We highlight the unrealized potential of
HAPS systems and elaborate on their unique ability to serve metropolitan areas.
The latest advancements and promising technologies in the HAPS energy and
payload systems are discussed. The integration of the emerging Reconfigurable
Smart Surface (RSS) technology in the communications payload of HAPS systems
for providing a cost-effective deployment is proposed. A detailed overview of
the radio resource management in HAPS systems is presented along with
synergistic physical layer techniques, including Faster-Than-Nyquist (FTN)
signaling. Numerous aspects of handoff management in HAPS systems are
described. The notable contributions of Artificial Intelligence (AI) in HAPS,
including machine learning in the design, topology management, handoff, and
resource allocation aspects are emphasized. The extensive overview of the
literature we provide is crucial for substantiating our vision that depicts the
expected deployment opportunities and challenges in the next 10 years
(next-generation networks), as well as in the subsequent 10 years
(next-next-generation networks).Comment: To appear in IEEE Communications Surveys & Tutorial
TRAFFIC ENGINEERING ALGORITHMS FOR SOFTWARE DEFINED SATELLITE-TERRESTRIAL NETWORKS
The telecom industry foresaw a constant change over the decades. Alongside the standardization of 5G, not only the traffic demand increased, but also the different requirements of the provided services, e.g., latency, traffic load and pattern, datarate. To match this trend, the traditional telecom infrastructure has been revolutionized, going from the "one-size-fits-all" model to a shared approach, where the infrastructure is shared among enterprise customers with even very different requirements. In this context, a paradigm, named network slicing, has considerably attracted the network operators. Network slicing is a successful enabling model for the 5G and beyond networks because it allows operators to tailor their networks based on the end use case, release unused functionalities and resources and dynamically assign them to different customers. In addition, 6G networks are advertised to bring the terrestrial and satellite networks closer, to work in a coordinated way and provide ubiquitous, heterogenous and reliable services. In this context, this thesis investigates the optimization of network slicing in an integrated satellite-terrestrial network. Well-known enabling technologies for network slicing, such as Software-Defined Networking (SDN), are included as a proof-of-concept SDN-based testbed to demonstrate and support the proposed optimization algorithms. As network slicing is a resource allocation problem, where virtualized resources are accommodated on the substrate network, we investigate this optimization problem that is well-known in the literature as Virtual Network Embedding (VNE). Firstly, we study the application of VNE to an integrated Medium Earth Orbit (MEO)terrestrial network with the objective of minimizing the traffic migrations, considering the existence of inter-satellite links (ISLs) too. As satellite handovers are unavoidable, we showed as including the minimization of traffic handovers in the objective function, brings to a gain in terms of traffic migrations and packet loss up to 2.5-5% compared to the traditional approaches. Secondly, we investigated the benefit of flexibly accommodating traffic demands without fully assigning the required resources while keeping the user satisfaction probability (USP) under control. Thanks to the SDN-based testbed, the traffic is generated and the statistics are collected to real-time match the need of each user. This showed an increase in the acceptance
ratio up to 11% compared to the baselines.
Lastly, as the previous two main chapters investigated the point-to-point connectivity, we expanded the work to the embedding of full slices for a combined Geostationary (GEO)-Low Earth Orbit (LEO) satellites and terrestrial network. We provided a flexible framework, for 6G use-cases with real network requirements, which operates based on prioritization, minimizes the migrations of slices when congestions occur over the substrate network and proactively manages the satellite handovers for each slice.
Finally, we discuss conclusive remarks and future research directions
Recommended from our members
A Connection Admission Control Framework for UMTS based Satellite Systems.An Adaptive Admission Control algorithm with pre-emption control mechanism for unicast and multicast communications in satellite UMTS.
In recent years, there has been an exponential growth in the use of
multimedia applications. A satellite system offers great potential for
multimedia applications with its ability to broadcast and multicast a large
amount of data over a very large area as compared to a terrestrial system.
However, the limited transmission capacity along with the dynamically
varying channel conditions impedes the delivery of good quality multimedia
service in a satellite system which has resulted in research efforts for deriving
efficient radio resource management techniques. This issue is addressed in
this thesis, where the main emphasis is to design a CAC framework which
maximizes the utilization of the scarce radio resources available in the
satellite and at the same time increases the performance of the system for a
UMTS based satellite system supporting unicast and multicast traffic.
The design of the system architecture for a UMTS based satellite system is
presented. Based on this architecture, a CAC framework is designed
consisting of three different functionalities: the admission control procedure,
the retune procedure and the pre-emption procedure. The joint use of these
functionalities is proposed to allow the performance of the system to be
maintained under congestion. Different algorithms are proposed for different
functionalities; an adaptive admission control algorithm, a greedy retune
algorithm and three pre-emption algorithms (Greedy, SubSetSum, and
Fuzzy).
A MATLAB simulation model is developed to study the performance of the
proposed CAC framework. A GUI is created to provide the user with the
flexibility to configure the system settings before starting a simulation. The
configuration settings allow the system to be analysed under different
conditions.
The performance of the system is measured under different simulation
settings such as enabling and disabling of the two functionalities of the CAC
framework; retune procedure and the pre-emption procedure. The simulation
results indicate the CAC framework as a whole with all the functionalities
performs better than the other simulation settings
Socio-economic aware data forwarding in mobile sensing networks and systems
The vision for smart sustainable cities is one whereby urban sensing is core to optimising city
operation which in turn improves citizen contentment. Wireless Sensor Networks are envisioned
to become pervasive form of data collection and analysis for smart cities but deployment of
millions of inter-connected sensors in a city can be cost-prohibitive. Given the ubiquity and
ever-increasing capabilities of sensor-rich mobile devices, Wireless Sensor Networks with Mobile
Phones (WSN-MP) provide a highly flexible and ready-made wireless infrastructure for future
smart cities. In a WSN-MP, mobile phones not only generate the sensing data but also relay the
data using cellular communication or short range opportunistic communication. The largest
challenge here is the efficient transmission of potentially huge volumes of sensor data over
sometimes meagre or faulty communications networks in a cost-effective way.
This thesis investigates distributed data forwarding schemes in three types of WSN-MP: WSN
with mobile sinks (WSN-MS), WSN with mobile relays (WSN-HR) and Mobile Phone Sensing
Systems (MPSS). For these dynamic WSN-MP, realistic models are established and distributed
algorithms are developed for efficient network performance including data routing and forwarding,
sensing rate control and and pricing. This thesis also considered realistic urban sensing
issues such as economic incentivisation and demonstrates how social network and mobility
awareness improves data transmission. Through simulations and real testbed experiments, it
is shown that proposed algorithms perform better than state-of-the-art schemes.Open Acces
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