11 research outputs found
Application and Performance Analysis of DSDV Routing Protocol in ad-hoc Wireless Sensor Network with Help of NS2 Knowledge
Wireless Sensor Networks (WSNs) are characterized by multi-hop wireless connectivity, frequently changing network topology and need for efficient routing protocols. The purpose of this paper is to evaluate performance of routing protocol DSDV in wireless sensor network (WSN) scales regarding the End-to-End delay and throughput PDR with mobility factor .Routing protocols are a critical aspect to performance in mobile wireless networks and play crucial role in determining network performance in terms of packet delivery fraction, end-to-end delay and packet loss. Destination-sequenced distance vector (DSDV) protocol is a proactive protocol depending on routing tables which are maintained at each node. The routing protocol should detect and maintain optimal route(s) between source and destination nodes. In this paper, we present application of DSDV in WSN as extend to our pervious study to the design and implementation the details of the DSDV routing protocol in MANET using the ns-2 network simulator. also, the performance of DSDV protocol in sensor network of randomly distributed mobile nodes with mobile source and sink nodes is investigated for MAC IEEE802.15.4 network by ns-2 simulator.
Distributed Closed-Loop Quasi-Orthogonal Space Time Block Coding with four relay Nodes: overcoming Imperfect Synchronization
In this paper, closed-loop quasi-orthogonal space time block
coding (QO-STBC) is exploited within a four relay node transmission
scheme to achieve full-rate and increase the available
diversity gain provided by earlier two relay approaches. The
problem of imperfect synchronization between relay nodes
is overcome by applying a parallel interference cancellation
(PIC) detection scheme at the destination node. Bit error rate
simulations confirm the advantages of the proposed methodology
for a range of levels of imperfect synchronization and
that only a small number of iterations is necessary within the
PIC detectio
Application independent in location tracking framework
Due to significant popularity of location-based services and multimedia communication over mobile devices, many researches have been conducted to extend the features of location tracking and make it cost effective to users. This research focuses on the performance of an indoor location tracking system on IPv6 network island with multiple real time applications that has location assisted session transfer feature for mobile users. Received signal strength Indicator mechanism has been used to locate the moving nodes. This research involved the development of location tracking server that monitors the dynamic and centralised MySQL database management system. Session initial protocols user agent has been used to deploy intercommunicating of multimedia data such as video and audio conference, text messaging among the moving nodes and users are able to transfer the multimedia sessions seamlessly to their nearest mobile nodes which will be determined by the location server. This study, thus, presents the variation of location tracking accuracy of triangulation system and fingerprint system on different indoor surroundings to compare the performance of their location tracking accuracy. Two indoor positioning systems, triangulation method (TM) and fingerprint method (FPM) were implemented and experiments were successfully conducted in different large area and small area scenarios of indoor environment. FPM experiments were examined into two sections: FPM database with data redundancy and FPM database without data redundancy. FPM database without data redundancy achieved 94.287% tracking accuracy which is the highest comparing to the FPM database with data redundancy and TM
Received signal strength–based indoor localization using a robust interacting multiple model–extended Kalman filter algorithm
Due to the vast increase in location-based services, currently there exists an actual need of robust and reliable indoor localization solutions. Received signal strength localization is widely used due to its simplicity and availability in most mobile devices. The received signal strength channel model is defined by the propagation losses and the shadow fading. In real-life applications, these parameters might vary over time because of changes in the environment. Thus, to obtain a reliable localization solution, they have to be sequentially estimated. In this article, the problem of tracking a mobile node by received signal strength measurements is addressed, simultaneously estimating the model parameters. Particularly, a two-slope path loss model is assumed for the received signal strength observations, which provides a more realistic representation of the propagation channel. The proposed methodology considers a parallel interacting multiple model–based architecture for distance estimation, which is coupled with the on-line estimation of the model parameters and the final position determination via Kalman filtering. Numerical simulation results in realistic scenarios are provided to support the theoretical discussion and to show the enhanced performance of the new robust indoor localization approach. Additionally, experimental results using real data are reported to validate the technique
Mobile Sensing Systems
[EN] Rich-sensor smart phones have made possible the recent birth of the mobile sensing research area as part of ubiquitous sensing which integrates other areas such as wireless sensor networks and web sensing. There are several types of mobile sensing: individual, participatory, opportunistic, crowd, social, etc. The object of sensing can be people-centered or environment-centered. The sensing domain can be home, urban, vehicular Currently there are barriers that limit the social acceptance of mobile sensing systems. Examples of social barriers are privacy concerns, restrictive laws in some countries and the absence of economic incentives that might encourage people to participate in a sensing campaign. Several technical barriers are phone energy savings and the variety of sensors and software for their management. Some existing surveys partially tackle the topic of mobile sensing systems. Published papers theoretically or partially solve the above barriers. We complete the above surveys with new works, review the barriers of mobile sensing systems and propose some ideas for efficiently implementing sensing, fusion, learning, security, privacy and energy saving for any type of mobile sensing system, and propose several realistic research challenges. The main objective is to reduce the learning curve in mobile sensing systems where the complexity is very high.This work has been partially supported by the "Ministerio de Ciencia e Innovacion", through the "Plan Nacional de I+D+i 2008-2011" in the "Subprograma de Proyectos de Investigacion Fundamental", project TEC2011-27516, and by the Polytechnic University of Valencia, through the PAID-05-12 multidisciplinary projects.Macias Lopez, EM.; Suarez Sarmiento, A.; Lloret, J. (2013). Mobile Sensing Systems. Sensors. 13(12):17292-17321. https://doi.org/10.3390/s131217292S1729217321131
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Cognitive radio systems in LTE networks
This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University London.The most important fact in the mobile industry at the moment is that demand for wireless services will continue to expand in the coming years. Therefore, it is vital to find more spectrums through cognitive radios for the growing numbers of services and users. However, the spectrum reallocations, enhanced receivers, shared use, or secondary markets-will not likely, by themselves or in combination, meet the real exponential increases in demand for wireless resources. Network operators will also need to re-examine network architecture, and consider integrating the fibre and wireless networks to address this issue. This thesis involves driving fibre deeper into cognitive networks, deploying microcells connected through fibre infrastructure to the backbone LTE networks, and developing the algorithms for diverting calls between the wireless and fibre systems, introducing new coexistence models, and mobility management. This research addresses the network deployment scenarios to a microcell-aided cognitive network, specifically slicing the spectrum spatially and providing reliable coverage at either tier. The goal of this research is to propose new method of decentralized-to-distributed management techniques that overcomes the spectrum unavailability barrier overhead in ongoing and future deployments of multi-tiered cognitive network architectures. Such adjustments will propose new opportunities in cognitive radio-to-fibre systematic investment strategies. Specific contributions include:
1) Identifying the radio access technologies and radio over fibre solution for cognitive network infrastructure to increase the uplink capacity analysis in two-tier networks.
2) Coexistence of macro and microcells are studied to propose a roadmap for optimising the deployment of cognitive microcells inside LTE macrocells in the case of considering radio over fibre access systems.
3) New method for roaming mobiles moving between microcells and macrocell coverage areas is proposed for managing spectrum handover, operator database, authentication and accounting by introducing the channel assigning agent entity. The ultimate goal is to reduce unnecessary channel adaptation
Cooperative Medium Access Mechanisms and Service-oriented Routing in Multi-hop Wireless Networks
Doktorgradsavhandling i informasjons- og kommunikasjonsteknologi, Universitetet i Agder, Grimstad, 2011Multi-hop wireless networks have been regarded as a promising path towards future
wireless communication landscape. In the past decade, most related work has been
performed in the context of mobile ad hoc networks. In very recent years, however,
much effort has been shifted to more static networks such as wireless mesh networks
and wireless sensor networks. While significant progress has been achieved through
these years, both theoretically and experimentally, challenges still exist in various
aspects of these networks. For instance, how to use multi-hop networks as a means
for providing broadband Internet services with reliability and balanced load remains
as a challenging task. As the number of end-users is increasing rapidly and more
and more users are enjoying multimedia services, how to provide Quality of Service
(QoS) with user satisfaction in such networks remains also as a hot topic.
Meanwhile, another direction which has recently attracted lots of efforts in the
international research community is the introduction of cooperative communications.
Cooperative communications based on relaying nodes are capable of improving
network performance in terms of increased spectral and power efficiency, extended
network coverage, balanced QoS, infrastructure-less deployment, etc. Cooperation
may happen at different communication layers, at the physical layer where
the received signal is retransmitted and at the MAC and routing layers where a
packet is forwarded to the next hop in a coordinated manner towards the destination,
respectively. However, without joint consideration and design of physical
layer, MAC layer and network layer, the benefit of cooperative communication cannot
be exploited to the maximum extent. In addition, how to extend one-hop cooperative
communication into multi-hop wireless network scenarios remains as an
almost un-chartered research frontier.
In this dissertation, we enhance the state of the art technologies in the field of
multi-hop wireless networks from a layered perspective. While efficient scheduling
mechanisms are proposed at the MAC layer, elaborate routing protocols are devised
at the network layer. More specifically, by taking into account of cross layer design
we cope with network congestion problems in wireless mesh networks mainly at the
network layer. In order to further improve the performance of cooperative wireless
networks, we propose a contention-based cooperative MAC protocol in the presence
of multiple relay nodes. Since a large majority of existing cooperative MAC
protocols are designed based on widely-used IEEE 802.11 MAC protocol which
exhibits inherent design constraint when applied in multi-hop wireless networks, it
is imperative to develop a novel cooperative MAC protocol which is appropriate
for multi-hop network scenarios. Next, we propose a TDMA-based MAC protocol supporting cooperative communications in static multi-hop wireless networks. Furthermore,
a cooperative lifetime maximization MAC protocol is proposed to cope
with the energy hole problem in wireless sensor networks