24,496 research outputs found
DSDV, DYMO, OLSR: Link Duration and Path Stability
In this paper, we evaluate and compare the impact of link duration and path
stability of routing protocols; Destination Sequence Distance vector (DSDV),
Dynamic MANET On- Demand (DYMO) and Optimized Link State Routing (OLSR) at
different number of connections and node density. In order to improve the
efficiency of selected protocols; we enhance DYMO and OLSR. Simulation and
comparison of both default and enhanced routing protocols is carried out under
the performance parameters; Packet Delivery Ratio (PDR), Average End-to End
Delay (AE2ED) and Normalized Routing Overhead (NRO). From the results, we
observe that DYMO performs better than DSDV, MOD-OLSR and OLSR in terms of PDR,
AE2ED, link duration and path stability at the cost of high value of NRO
Optimal Algorithms for Near-Hitless Network Restoration via Diversity Coding
Diversity coding is a network restoration technique which offers near-hitless
restoration, while other state-of-the art techniques are significantly slower.
Furthermore, the extra spare capacity requirement of diversity coding is
competitive with the others. Previously, we developed heuristic algorithms to
employ diversity coding structures in networks with arbitrary topology. This
paper presents two algorithms to solve the network design problems using
diversity coding in an optimal manner. The first technique pre-provisions
static traffic whereas the second technique carries out the dynamic
provisioning of the traffic on-demand. In both cases, diversity coding results
in smaller restoration time, simpler synchronization, and much reduced
signaling complexity than the existing techniques in the literature. A Mixed
Integer Programming (MIP) formulation and an algorithm based on Integer Linear
Programming (ILP) are developed for pre-provisioning and dynamic provisioning,
respectively. Simulation results indicate that diversity coding has
significantly higher restoration speed than Shared Path Protection (SPP) and
p-cycle techniques. It requires more extra capacity than the p-cycle technique
and SPP. However, the increase in the total capacity is negligible compared to
the increase in the restoration speed.Comment: An old version of this paper is submitted to IEEE Globecom 2012
conferenc
Cross-layer design of multi-hop wireless networks
MULTI -hop wireless networks are usually defined as a collection of nodes
equipped with radio transmitters, which not only have the capability to
communicate each other in a multi-hop fashion, but also to route each others’ data
packets. The distributed nature of such networks makes them suitable for a variety of
applications where there are no assumed reliable central entities, or controllers, and
may significantly improve the scalability issues of conventional single-hop wireless
networks.
This Ph.D. dissertation mainly investigates two aspects of the research issues
related to the efficient multi-hop wireless networks design, namely: (a) network
protocols and (b) network management, both in cross-layer design paradigms to
ensure the notion of service quality, such as quality of service (QoS) in wireless mesh
networks (WMNs) for backhaul applications and quality of information (QoI) in
wireless sensor networks (WSNs) for sensing tasks. Throughout the presentation of
this Ph.D. dissertation, different network settings are used as illustrative examples,
however the proposed algorithms, methodologies, protocols, and models are not
restricted in the considered networks, but rather have wide applicability.
First, this dissertation proposes a cross-layer design framework integrating
a distributed proportional-fair scheduler and a QoS routing algorithm, while using
WMNs as an illustrative example. The proposed approach has significant performance
gain compared with other network protocols. Second, this dissertation proposes
a generic admission control methodology for any packet network, wired and
wireless, by modeling the network as a black box, and using a generic mathematical
0. Abstract 3
function and Taylor expansion to capture the admission impact. Third, this dissertation
further enhances the previous designs by proposing a negotiation process,
to bridge the applications’ service quality demands and the resource management,
while using WSNs as an illustrative example. This approach allows the negotiation
among different service classes and WSN resource allocations to reach the optimal
operational status. Finally, the guarantees of the service quality are extended to
the environment of multiple, disconnected, mobile subnetworks, where the question
of how to maintain communications using dynamically controlled, unmanned data
ferries is investigated
A survey on OFDM-based elastic core optical networking
Orthogonal frequency-division multiplexing (OFDM) is a modulation technology that has been widely adopted in many new and emerging broadband wireless and wireline communication systems. Due to its capability to transmit a high-speed data stream using multiple spectral-overlapped lower-speed subcarriers, OFDM technology offers superior advantages of high spectrum efficiency, robustness against inter-carrier and inter-symbol interference, adaptability to server channel conditions, etc. In recent years, there have been intensive studies on optical OFDM (O-OFDM) transmission technologies, and it is considered a promising technology for future ultra-high-speed optical transmission. Based on O-OFDM technology, a novel elastic optical network architecture with immense flexibility and scalability in spectrum allocation and data rate accommodation could be built to support diverse services and the rapid growth of Internet traffic in the future. In this paper, we present a comprehensive survey on OFDM-based elastic optical network technologies, including basic principles of OFDM, O-OFDM technologies, the architectures of OFDM-based elastic core optical networks, and related key enabling technologies. The main advantages and issues of OFDM-based elastic core optical networks that are under research are also discussed
Analysis and Modeling Experiment Performance Parameters of Routing Protocols in MANETs and VANETs
In this paper, a framework for experimental parameters in which Packet
Delivery Ratio (PDR), effect of link duration over End-to-End Delay (E2ED) and
Normalized Routing Overhead (NRO) in terms of control packets is analyzed and
modeled for Mobile Ad-Hoc NETworks (MANETs) and Vehicular Ad-Hoc NETworks
(VANETs) with the assumption that nodes (vehicles) are sparsely moving in two
different road. Moreover, this paper contributes the performance comparison of
one Proactive Routing Protocol; Destination Sequenced Distance vector (DSDV)
and two reactive protocols; DYnamic Source Routing (DSR) and DYnamic MANET
On-Demand (DYMO). A novel contribution of this work is enhancements in default
versions of selected routing protocols. Three performance parameters; PDR, E2ED
and NRO with varying scalabilities are measured to analyze the performance of
selected routing protocols with their original and enhanced versions. From
extensive simulations, it is observed that DSR outperforms among all three
protocols at the cost of delay. NS-2 simulator is used for simulation with
TwoRayGround propagation model to evaluate analytical results
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