55,036 research outputs found
Communication models for monitoring and mobility verification in mission critical wireless networks
Recent technological advances have seen wireless sensor networks emerge as an interesting research topic because of its ability to realize mission critical applications like in military or wildfire detection. The first part of the thesis focuses on the development of a novel communication scheme referred here as a distributed wireless critical information-aware maintenance network (DWCIMN), which is presented for preventive maintenance of network-centric dynamic systems. The proposed communication scheme addresses quality of service (QoS) issues by using a combination of a head-of-the-line queuing scheme, efficient bandwidth allocation, weight-based backoff mechanism, and a distributed power control scheme. A thorough analysis of a head-of-the-line priority queuing scheme is given for a single-server, finite queue with a batch arrival option and user priorities. The scheme is implemented in the Network Simulator (NS-2), and the results demonstrate reduced queuing delays and efficient bandwidth allocation for time-critical data over non time critical data. In the second part, we introduce a unique mobility verification problem in wireless sensor networks wherein the objective is to verify the claimed mobility path of a node in a co-operating mission critical operation between two allies. We address this problem by developing an efficient power-control based mobility verification model. The simulation framework is implemented in Matlab and the results indicate successful detection of altered claimed paths within a certain error bound --Abstract, page iii
Towards a System Theoretic Approach to Wireless Network Capacity in Finite Time and Space
In asymptotic regimes, both in time and space (network size), the derivation
of network capacity results is grossly simplified by brushing aside queueing
behavior in non-Jackson networks. This simplifying double-limit model, however,
lends itself to conservative numerical results in finite regimes. To properly
account for queueing behavior beyond a simple calculus based on average rates,
we advocate a system theoretic methodology for the capacity problem in finite
time and space regimes. This methodology also accounts for spatial correlations
arising in networks with CSMA/CA scheduling and it delivers rigorous
closed-form capacity results in terms of probability distributions. Unlike
numerous existing asymptotic results, subject to anecdotal practical concerns,
our transient one can be used in practical settings: for example, to compute
the time scales at which multi-hop routing is more advantageous than single-hop
routing
Drone Mobile Networks: Performance Analysis Under 3D Tractable Mobility Models
Reliable wireless communication networks are a significant but challenging mission for
post-disaster areas and hotspots in the era of information. However, with the maturity of unmanned aerial
vehicle (UAV) technology, drone mobile networks have attracted considerable attention as a prominent solution for facilitating critical communications. This paper provides a system-level analysis for drone mobile
networks on a finite three-dimensional (3D) space. Our aim is to explore the fundamental performance limits
of drone mobile networks taking into account practical considerations. Most existing works on mobile drone
networks use simplified mobility models (e.g., fixed height), but the movement of the drones in practice is
significantly more complicated, which leads to difficulties in analyzing the performance of the drone mobile
networks. Hence, to tackle this problem, we propose a stochastic geometry-based framework with a number
of different mobility models including a random Brownian motion approach. The proposed framework allows
to circumvent the extremely complex reality model and obtain upper and lower performance bounds for
drone networks in practice. Also, we explicitly consider certain constraints, such as the small-scale fading
characteristics relying on line-of-sight (LOS) and non line-of-sight (NLOS) propagation, and multi-antenna
operations. The validity of the mathematical findings is verified via Monte-Carlo (MC) simulations for
various network settings. In addition, the results reveal some design guidelines and important trends for
the practical deployment of drone networks
Spatial networks with wireless applications
Many networks have nodes located in physical space, with links more common
between closely spaced pairs of nodes. For example, the nodes could be wireless
devices and links communication channels in a wireless mesh network. We
describe recent work involving such networks, considering effects due to the
geometry (convex,non-convex, and fractal), node distribution,
distance-dependent link probability, mobility, directivity and interference.Comment: Review article- an amended version with a new title from the origina
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