1,721,055 research outputs found
IP Mobile Multicast over Next Generation Satellite Networks. Design and Evaluation of a Seamless Mobility Framework for IP Multicast Communications over a Multi-beam Geostationary Satellite Network
Get PDFThe inherent broadcast nature of satellites, their global coverage and direct
access to a large number of subscribers give satellites unrivalled advantages in
supporting IP multicast applications. A new generation of satellite systems that
support regenerative on-board processors and multiple spot beam technology
have opened new possibilities of implementing IP multicast communication over
satellites. These new features enable satellites to make efficient use of their
allocated bandwidth resources and provide cost effective network services but
equally, create new challenges for mobile satellite terminals. IP mobility support
in general and IP mobile multicast support in particular on mobile satellite
terminals like the ones mounted on continental flights, maritime vessels, etc.,
still remain big challenges that have received very little attention from the
research community.
Up till now, there are no proposed mechanisms to support IP multicast for
mobile receivers/sources in multi-beam satellite networks in open literature.
This study explores the suitability of IP multicast mobility support schemes
defined for terrestrial networks in a satellite environment and proposes novel
schemes based on the concepts of Home and Remote subscription-based approaches, multiple interface and PMIPv6 protocol. Detailed analysis and
comparison of results obtained from the proposed schemes, Mobile IP (MIP)
Home and Remote subscription-based approaches (for terrestrial networks)
when implemented on a reference multi-beam satellite network are presented.
From these results, the proposed schemes outperform the MIP Home and
Remote subscription-based approaches in terms of gateway handover latency,
number of multicast packets lost and signalling cost over the satellite air
interface
Wireless mosaic eyes based robot path planning and control. Autonomous robot navigation using environment intelligence with distributed vision sensors.
No full textAs an attempt to steer away from developing an autonomous robot with complex centralised intelligence, this thesis proposes an intelligent environment infrastructure where intelligences are distributed in the environment through collaborative vision sensors mounted in a physical architecture, forming a wireless sensor network, to enable the navigation of unintelligent robots within that physical architecture. The aim is to avoid the bottleneck of centralised robot intelligence that hinders the application and exploitation of autonomous robot. A bio-mimetic snake algorithm is proposed to coordinate the distributed vision sensors for the generation of a collision free Reference-snake (R-snake) path during the path planning process. By following the R-snake path, a novel Accompanied snake (A-snake) method that complies with the robot's nonholonomic constraints for trajectory generation and motion control is introduced to generate real time robot motion commands to navigate the robot from its current position to the target position. A rolling window optimisation mechanism subject to control input saturation constraints is carried out for time-optimal control along the A-snake. A comprehensive simulation software and a practical distributed intelligent environment with vision sensors mounted on a building ceiling are developed. All the algorithms proposed in this thesis are first verified by the simulation and then implemented in the practical intelligent environment. A model car with less on-board intelligence is successfully controlled by the distributed vision sensors and demonstrated superior mobility
Network Coding for Multihop Wireless Networks: Joint Random Linear Network Coding and Forward Error Correction with Interleaving for Multihop Wireless Networks
Get PDFOptimising the throughput performance for wireless networks is one of the
challenging tasks in the objectives of communication engineering, since wireless
channels are prone to errors due to path losses, random noise, and fading
phenomena. The transmission errors will be worse in a multihop scenario due to its
accumulative effects. Network Coding (NC) is an elegant technique to improve the
throughput performance of a communication network. There is the fact that the bit
error rates over one modulation symbol of 16- and higher order- Quadrature
Amplitude Modulation (QAM) scheme follow a certain pattern. The Scattered
Random Network Coding (SRNC) system was proposed in the literature to exploit
the error pattern of 16-QAM by using bit-scattering to improve the throughput of
multihop network to which is being applied the Random Linear Network Coding
(RLNC). This thesis aims to improve further the SRNC system by using Forward
Error Correction (FEC) code; the proposed system is called Joint RLNC and FEC
with interleaving.
The first proposed system (System-I) uses Convolutional Code (CC) FEC. The
performances analysis of System-I with various CC rates of 1/2, 1/3, 1/4, 1/6, and
1/8 was carried out using the developed simulation tools in MATLAB and compared
to two benchmark systems: SRNC system (System-II) and RLNC system (System-
III). The second proposed system (System-IV) uses Reed-Solomon (RS) FEC
code. Performance evaluation of System IV was carried out and compared to three
systems; System-I with 1/2 CC rate, System-II, and System-III. All simulations were
carried out over three possible channel environments: 1) AWGN channel, 2) a
Rayleigh fading channel, and 3) a Rician fading channel, where both fading
channels are in series with the AWGN channel. The simulation results show that
the proposed system improves the SRNC system. How much improvement gain
can be achieved depends on the FEC type used and the channel environment.Indonesian Government and the University of Bradfor
Managing Next Generation Networks (NGNs) based on the Service-Oriented Architechture (SOA). Design, Development and testing of a message-based Network Management platform for the integration of heterogeneous management systems.
No full textNext Generation Networks (NGNs) aim to provide a unified network
infrastructure to offer multimedia data and telecommunication services
through IP convergence. NGNs utilize multiple broadband, QoS-enabled
transport technologies, creating a converged packet-switched network
infrastructure, where service-related functions are separated from the
transport functions. This requires significant changes in the way how
networks are managed to handle the complexity and heterogeneity of
NGNs.
This thesis proposes a Service Oriented Architecture (SOA) based
management framework that integrates heterogeneous management
systems in a loose coupling manner. The key benefit of the proposed
management architecture is the reduction of the complexity through
service and data integration. A network management middleware layer
that merges low level management functionality with higher level
management operations to resolve the problem of heterogeneity was
proposed.
A prototype was implemented using Web Services and a testbed was
developed using trouble ticket systems as the management application to
demonstrate the functionality of the proposed framework. Test results
show the correcting functioning of the system. It also concludes that the
proposed framework fulfils the principles behind the SOA philosophy
Load balancing in heterogeneous wireless communications networks. Optimized load aware vertical handovers in satellite-terrestrial hybrid networks incorporating IEEE 802.21 media independent handover and cognitive algorithms.
No full textHeterogeneous wireless networking technologies such as satellite, UMTS, WiMax and WLAN are being used to provide network access for both voice and data services. In big cities, the densely populated areas like town centres, shopping centres and train stations may have coverage of multiple wireless networks. Traditional Radio Access Technology (RAT) selection algorithms are mainly based on the ¿Always Best Connected¿ paradigm whereby the mobile nodes are always directed towards the available network which has the strongest and fastest link. Hence a large number of mobile users may be connected to the more common UMTS while the other networks like WiMax and WLAN would be underutilised, thereby creating an unbalanced load across these different wireless networks. This high variation among the load across different co-located networks may cause congestion on overloaded network leading to high call blocking and call dropping probabilities. This can be alleviated by moving mobile users from heavily loaded networks to least loaded networks.
This thesis presents a novel framework for load balancing in heterogeneous wireless networks incorporating the IEEE 802.21 Media Independent Handover (MIH). The framework comprises of novel load-aware RAT selection techniques and novel network load balancing mechanism. Three new different load balancing algorithms i.e. baseline, fuzzy and neural-fuzzy algorithms have also been presented in this thesis that are used by the framework for efficient load balancing across the different co-located wireless networks. A simulation model developed in NS2 validates the performance of the proposed load balancing framework. Different attributes like load distribution in all wireless networks, handover latencies, packet drops, throughput at mobile nodes and network utilization have been observed to evaluate the effects of load balancing using different scenarios. The simulation results indicate that with load balancing the performance efficiency improves as the overloaded situation is avoided by load balancing
Energy Efficient Cloud Computing Based Radio Access Networks in 5G. Design and evaluation of an energy aware 5G cloud radio access networks framework using base station sleeping, cloud computing based workload consolidation and mobile edge computing
Get PDFFifth Generation (5G) cellular networks will experience a thousand-fold increase in data traffic with over 100 billion connected devices by 2020. In order to support this skyrocketing traffic demand, smaller base stations (BSs) are deployed to increase capacity. However, more BSs increase energy consumption which contributes to operational expenditure (OPEX) and CO2 emissions. Also, an introduction of a plethora of 5G applications running in the mobile devices cause a significant amount of energy consumption in the mobile devices. This thesis presents a novel framework for energy efficiency in 5G cloud radio access networks (C-RAN) by leveraging cloud computing technology. Energy efficiency is achieved in three ways; (i) at the radio side of H-C-RAN (Heterogeneous C-RAN), a dynamic BS switching off algorithm is proposed to minimise energy consumption while maintaining Quality of Service (QoS), (ii) in the BS cloud, baseband workload consolidation schemes are proposed based on simulated annealing and genetic algorithms to minimise energy consumption in the cloud, where also advanced fuzzy based admission control with pre-emption is implemented to improve QoS and resource utilisation (iii) at the mobile device side, Mobile Edge Computing (MEC) is used where computer intensive tasks from the mobile device are executed in the MEC server in the cloud. The simulation results show that the proposed framework effectively reduced energy consumption by up to 48% within RAN and 57% in the mobile devices, and improved network energy efficiency by a factor of 10, network throughput by a factor of 2.7 and resource utilisation by 54% while maintaining QoS
Intelligent based Packet Scheduling Scheme using Internet Protocol/Multi-Protocol Label Switching (IP/MPLS) Technology for 5G. Design and Investigation of Bandwidth Management Technique for Service-Aware Traffic Engineering using Internet Protocol/Multi-Protocol Label Switching (IP/MPLS) for 5G
Get PDFMulti-Protocol Label Switching (MPLS) makes use of traffic engineering (TE)
techniques and a variety of protocols to establish pre-determined highly
efficient routes in Wide Area Network (WAN). Unlike IP networks in which
routing decision has to be made through header analysis on a hop-by-hop
basis, MPLS makes use of a short bit sequence that indicates the forwarding
equivalence class (FEC) of a packet and utilises a predefined routing table to
handle packets of a specific FEC type. Thus header analysis of packets is not
required, resulting in lower latency. In addition, packets of similar
characteristics can be routed in a consistent manner. For example, packets
carrying real-time information can be routed to low latency paths across the
networks. Thus the key success to MPLS is to efficiently control and distribute
the bandwidth available between applications across the networks.
A lot of research effort on bandwidth management in MPLS networks has
already been devoted in the past. However, with the imminent roll out of 5G,
MPLS is seen as a key technology for mobile backhaul. To cope with the 5G
demands of rich, context aware and multimedia-based user applications, more
efficient bandwidth management solutions need to be derived.
This thesis focuses on the design of bandwidth management algorithms, more
specifically QoS scheduling, in MPLS network for 5G mobile backhaul. The
aim is to ensure the reliability and the speed of packet transfer across the
network. As 5G is expected to greatly improve the user experience with
innovative and high quality services, users’ perceived quality of service (QoS)
needs to be taken into account when deriving such bandwidth management
solutions. QoS expectation from users are often subjective and vague. Thus
this thesis proposes the use of fuzzy logic based solution to provide service aware and user-centric bandwidth management in order to satisfy
requirements imposed by the network and users.
Unfortunately, the disadvantage of fuzzy logic is scalability since dependable
fuzzy rules and membership functions increase when the complexity of being
modelled increases. To resolve this issue, this thesis proposes the use of neuro-fuzzy to solicit interpretable IF-THEN rules.The algorithms are
implemented and tested through NS2 and Matlab simulations. The
performance of the algorithms are evaluated and compared with other
conventional algorithms in terms of average throughput, delay, reliability, cost,
packet loss ratio, and utilization rate.
Simulation results show that the neuro-fuzzy based algorithm perform better
than fuzzy and other conventional packet scheduling algorithms using IP and
IP over MPLS technologies.Tertiary Education Trust Fund (TETFUND
Scheduling and Resource Efficiency Balancing: Discrete Species Conserving Cuckoo Search for Scheduling in an Uncertain Execution Environment
Get PDFThe main goal of a scheduling process is to decide when and how to execute each of the project’s activities. Despite large variety of researched scheduling problems, the majority of them can be described as generalisations of the resource-constrained project scheduling problem (RCPSP). Because of wide applicability and challenging difficulty, RCPSP has attracted vast amount of attention in the research community and great variety of heuristics have been adapted for solving it. Even though these heuristics are structurally different and operate according to diverse principles, they are designed to obtain only one solution at a time. In the recent researches on RCPSPs, it was proven that these kind of problems have complex multimodal fitness landscapes, which are characterised by a wide solution search spaces and presence of multiple local and global optima.
The main goal of this thesis is twofold. Firstly, it presents a variation of the RCPSP that considers optimisation of projects in an uncertain environment where resources are modelled to adapt to their environment and, as the result of this, improve their efficiency. Secondly, modification of a novel evolutionary computation method Cuckoo Search (CS) is proposed, which has been adapted for solving combinatorial optimisation problems and modified to obtain multiple solutions. To test the proposed methodology, two sets of experiments are carried out. First, the developed algorithm is applied to a real-life software development project. Second, performance of the algorithm is tested on universal benchmark instances for scheduling problems which were modified to take into account specifics of the proposed optimisation model. The results of both experiments demonstrate that the proposed methodology achieves competitive level of performance and is capable of finding multiple global solutions, as well as prove its applicability in real-life projects
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.
No full textIn 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
A service orientated architecture and wireless sensor network approach applied to the measurement and visualisation of a micro injection moulding process. Design, development and testing of an ESB based micro injection moulding platform using Google Gadgets and business processes for the integration of disparate hardware systems on the factory shop floor
Get PDFFactory shop floors of the future will see a significant increase in interconnected devices for monitoring and control. However, if a Service Orientated Architecture (SOA) is implemented on all such devices then this will result in a large number of permutations of services and composite services. These services combined with other business level components can pose a huge challenge to manage as it is often difficult to keep an overview of all the devices, equipment and services. This thesis proposes an SOA based novel assimilation architecture for integrating disparate industrial hardware based processes and business processes of an enterprise in particular the plastics machinery environment. The key benefits of the proposed architecture are the reduction of complexity when integrating disparate hardware platforms; managing the associated services as well as allowing the Micro Injection Moulding (µIM) process to be monitored on the web through service and data integration. An Enterprise Service Bus (ESB) based middleware layer integrates the Wireless Sensor Network (WSN) based environmental and simulated machine process systems with frontend Google Gadgets (GGs) based web visualisation applications. A business process framework is proposed to manage and orchestrate the resulting services from the architecture.
Results from the analysis of the WSN kits in terms of their usability and reliability showed that the Jennic WSN was easy to setup and had a reliable communication link in the polymer industrial environment with the PER being below 0.5%. The prototype Jennic WSN based µIM process monitoring system had limitations when monitoring high-resolution machine data, therefore a novel hybrid integration architecture was proposed. The assimilation architecture was implemented on a distributed server based test bed. Results from test scenarios showed that the architecture was highly scalable and could potentially allow a large number of disparate sensor based hardware systems and services to be hosted, managed, visualised and linked to form a cohesive business process
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