179 research outputs found
Mobile Networks
The growth in the use of mobile networks has come mainly with the third generation systems and voice traffic. With the current third generation and the arrival of the 4G, the number of mobile users in the world will exceed the number of landlines users. Audio and video streaming have had a significant increase, parallel to the requirements of bandwidth and quality of service demanded by those applications. Mobile networks require that the applications and protocols that have worked successfully in fixed networks can be used with the same level of quality in mobile scenarios. Until the third generation of mobile networks, the need to ensure reliable handovers was still an important issue. On the eve of a new generation of access networks (4G) and increased connectivity between networks of different characteristics commonly called hybrid (satellite, ad-hoc, sensors, wired, WIMAX, LAN, etc.), it is necessary to transfer mechanisms of mobility to future generations of networks. In order to achieve this, it is essential to carry out a comprehensive evaluation of the performance of current protocols and the diverse topologies to suit the new mobility conditions
A Novel Adaptive Channel Allocation Scheme to Handle Handoffs
Wireless networking is becoming an increasingly important and popular way of
providing global information access to users on the move. One of the main
challenges for seamless mobility is the availability of simple and robust
handoff algorithms, which allow a mobile node to roam among heterogeneous
wireless networks. In this paper, the authors devise a scheme, A Novel Adaptive
Channel Allocation Scheme (ACAS) where the number of guard channel(s) is
adjusted automatically based on the average handoff blocking rate measured in
the past certain period of time. The handoff blocking rate is controlled under
the designated threshold and the new call blocking rate is minimized. The
performance evaluation of the ACAS is done through simulation of nodes. The
result shows that the ACAS scheme outperforms the Static Channel Allocation
Scheme by controlling a hard constraint on the handoff rejection probability.
The proposed scheme achieves the optimal performance by maximizing the resource
utilization and adapts itself to changing traffic conditions automatically.Comment: 9 Pages; in International Journal of Distributed and Parallel system
Efficient Utilization of Channels Using Dynamic Guard Channel Allocation with Channel Borrowing Strategy in Handoffs
User mobility in wireless data networks is increasing because of
technological advances and the desire for voice and multimedia applications.
These applications, however, require fast handoffs between base stations to
maintain the quality of the connections. In this paper, the authors describe
the use of novel and efficient data structure which dynamically allocates guard
channel for handoffs and introduces the concept of channel borrowing strategy.
The proposed scheme allocates the guard channels for handoff requests
dynamically, based on the traffic load for certain time period. A new
originating call in the cell coverage area also uses these guard channels if
they are unused. Our basic idea is to allow Guard channels to be shared between
new calls and handoff calls. This approach maximizes the channel utilization.
The simulation results prove that the channel borrowing scheme improves the
overall throughput.Comment: International Conference CCSEA 2012 at New Delhi May 27. arXiv admin
note: substantial text overlap with arXiv:1206.306
Recent Advances in Wireless Communications and Networks
This book focuses on the current hottest issues from the lowest layers to the upper layers of wireless communication networks and provides "real-time" research progress on these issues. The authors have made every effort to systematically organize the information on these topics to make it easily accessible to readers of any level. This book also maintains the balance between current research results and their theoretical support. In this book, a variety of novel techniques in wireless communications and networks are investigated. The authors attempt to present these topics in detail. Insightful and reader-friendly descriptions are presented to nourish readers of any level, from practicing and knowledgeable communication engineers to beginning or professional researchers. All interested readers can easily find noteworthy materials in much greater detail than in previous publications and in the references cited in these chapters
Analysis of BGP4 Peering Establishment Time on IPv6 Connection over 6PE and 6VPE
Nowadays, because of the exhaustion of IPv4 address space, IPv6 is increasingly being used on enterprise networks. Usually, an enterprise uses an MPLS network from a Service Provider to interconnect their IPv4 network sites. Although MPLS Service Providers mostly built their MPLS backbone based on IPv4, their MPLS backbone have the capability to transport IPv6 traffic of their customers. Two methods can be used by the MPLS Service Provider to connect its customer IPv6 network, which is 6PE (IPv6 Provider Edge Routers) and 6VPE (IPv6 VPN Provider Edge Router). Enterprises generally use a BGP routing protocol to interconnect their networks, and they need to use the best method that suits their requirement from their MPLS Service Provider to transport their IPv6 traffic (including the BGP protocol). The MPLS Service Providers need to consider the advantages and disadvantages of both methods. This paper illustrates the analysis of BGP4 (current BGP version) IPv6 peering establishment time over 6PE and 6VPE methods. The MPLS Service Providers can use the analysis results of this study to determine the suited method to interconnect its customers' IPv6 networks
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Radio network management in cognitive LTE-Femtocell Systems
This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University London.There is a strong uptake of femtocell deployment as small cell application
platforms in the upcoming LTE networks. In such two-tier networks of LTEfemtocell
base stations, a large portion of the assigned spectrum is used
sporadically leading to underutilisation of valuable frequency resources.
Novel spectrum access techniques are necessary to solve these current spectrum
inefficiency problems. Therefore, spectrum management solutions should have
the features to improve spectrum access in both temporal and spatial manner.
Cognitive Radio (CR) with the Dynamic Spectrum Access (DSA) is considered
to be the key technology in this research in order to increase the spectrum
efficiency. This is an effective solution to allow a group of Secondary Users
(SUs) to share the radio spectrum initially allocated to the Primary User (PUs) at
no interference.
The core aim of this thesis is to develop new cognitive LTE-femtocell systems
that offer a 4G vision, to facilitate the radio network management in order to
increase the network capacity and further improve spectrum access probabilities.
In this thesis, a new spectrum management model for cognitive radio networks is
considered to enable a seamless integration of multi-access technology with
existing networks. This involves the design of efficient resource allocation
algorithms that are able to respond to the rapid changes in the dynamic wireless
environment and primary users activities. Throughout this thesis a variety of
network upgraded functions are developed using application simulation
scenarios. Therefore, the proposed algorithms, mechanisms, methods, and system
models are not restricted in the considered networks, but rather have a wider
applicability to be used in other technologies.
This thesis mainly investigates three aspects of research issues relating to the
efficient management of cognitive networks: First, novel spectrum resource
management modules are proposed to maximise the spectrum access by rapidly
detecting the available transmission opportunities. Secondly, a developed pilot
power controlling algorithm is introduced to minimise the power consumption by
considering mobile position and application requirements. Also, there is
investigation on the impact of deploying different numbers of femtocell base
stations in LTE domain to identify the optimum cell size for future networks.
Finally, a novel call admission control mechanism for mobility management is
proposed to support seamless handover between LTE and femtocell domains.
This is performed by assigning high speed mobile users to the LTE system to
avoid unnecessary handovers.
The proposed solutions were examined by simulation and numerical analysis to
show the strength of cognitive femtocell deployment for the required
applications. The results show that the new system design based on cognitive
radio configuration enable an efficient resource management in terms of
spectrum allocation, adaptive pilot power control, and mobile handover. The
proposed framework and algorithms offer a novel spectrum management for self organised LTE-femtocell architecture.
Eventually, this research shows that certain architectures fulfilling spectrum
management requirements are implementable in practice and display good
performance in dynamic wireless environments which recommends the
consideration of CR systems in LTE and femtocell networks
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