Results 11 -
18 of
18
Wireless ad hoc networks with tunable topology
- In: Proceedings of the 45th Annual Allerton Conference on Communication, Control and Computing
, 2007
"... Abstract — We study the set of connectivity and topological ..."
Abstract
-
Cited by 7 (5 self)
- Add to MetaCart
(Show Context)
Abstract — We study the set of connectivity and topological
Failure-Resilient Ad Hoc and Sensor Networks in a Shadow Fading Environment
"... This paper addresses the topological design of wireless multihop networks that are robust against node failures. Given is the following scenario: The nodes are randomly distributed according to a homogeneous Poisson point pro-cess of density ρ, each node has the same transmission capabilities, and t ..."
Abstract
-
Cited by 4 (0 self)
- Add to MetaCart
(Show Context)
This paper addresses the topological design of wireless multihop networks that are robust against node failures. Given is the following scenario: The nodes are randomly distributed according to a homogeneous Poisson point pro-cess of density ρ, each node has the same transmission capabilities, and the wireless channel suffers from a log normal shadow fading. We investigate the minimum node density ρ required to ensure that all nodes inside a ran-domly chosen area of size A are kconnected with high probability (k2N). We derive a tight lower bound for this node density as a function of the channel parameters and compute it for a number of scenarios. The results give in-sight into how fading affects the network topology.
Connectivity Analysis of Wireless Ad Hoc Networks With Beamforming
"... Abstract-In this paper, we present an analytical model for evaluating the impact of shadowing and beamforming on the connectivity of wireless ad hoc networks accommodating nodes equipped with multiple antennas. We consider two simple beamforming schemes: random beamforming, where each node selects ..."
Abstract
- Add to MetaCart
Abstract-In this paper, we present an analytical model for evaluating the impact of shadowing and beamforming on the connectivity of wireless ad hoc networks accommodating nodes equipped with multiple antennas. We consider two simple beamforming schemes: random beamforming, where each node selects a main beam direction randomly with no coordination with other nodes, and center-directed beamforming, where each node points its main beam toward the geographical center of the network. Taking path loss, shadowing, and beamforming into account, we derive an expression for the effective coverage area of a node, which is used to analyze both the local network connectivity (probability of node isolation) and the overall network connectivity (1-connectivity and path probability). We verify the correctness of our analytical approach by comparing with simulations. Our results show that the presence of shadowing increases the probability of node isolation and reduces the 1-connectivity of the network, although moderate shadowing can improve the path probability between two nodes. Furthermore, we show that the impact of beamforming strongly depends on the level of the channel path loss. In particular, compared with omnidirectional antennas, beamforming improves both the local and the overall connectivity for a path loss exponent of α < 3. The analysis in this paper provides an efficient way for system designers to characterize and optimize the connectivity of wireless ad hoc networks with beamforming.
Advisor
"... Wireless Ad-hoc networks are self-organizing networks without any preexisting infrastructure to communicate. A key characteristic of these networks is the lack of centralized administration and existence of a dynamic topology. In such a dynamically changing topology, we need all the nodes to have th ..."
Abstract
- Add to MetaCart
(Show Context)
Wireless Ad-hoc networks are self-organizing networks without any preexisting infrastructure to communicate. A key characteristic of these networks is the lack of centralized administration and existence of a dynamic topology. In such a dynamically changing topology, we need all the nodes to have the ability of routing. In the wireless medium, due to the radio transmission range limitations, communication among nodes has to be established through a multi-hop path. To accomplish this task, various routing protocols have been proposed that are capable of adapting to the changes in the network topology. However, in order to understand the functions of the routing protocols and their performance in a wireless network, we need to have a good understanding of the structural properties of the underlying network. In the first part of this study, we look at the problem of message delivery in small-world networks, and validate the related theory using a modified, but more realistic for wireless network, model. In the second part of the study, we propose a probabilistic geographic routing protocol for wireless ad-hoc networks. We present the simulation results for the routing algorithm along with the
The Impacts of Radio Channels and Node Mobility on Link Statistics in Mobile Ad Hoc Networks
"... Abstract — Understanding link statistics in mobile ad hoc net-works (MANETs) is essential to design adaptive routing protocols and achieve desired network performance. While much attention has been given to the node mobility impacts, little has been done to investigate the influence of dynamic chann ..."
Abstract
- Add to MetaCart
(Show Context)
Abstract — Understanding link statistics in mobile ad hoc net-works (MANETs) is essential to design adaptive routing protocols and achieve desired network performance. While much attention has been given to the node mobility impacts, little has been done to investigate the influence of dynamic channel fadings and the joint effects of the interactions among radio channels, transmission range, node mobility and node-pair distance on link statistics. In this paper, we investigate the link stability and availability by using a distance transition probability matrix of a relative distance between two nodes. Our analysis takes the node effective transmission range Re into account. The relative node movement is based on the Semi-Markov Smooth (SMS) mobility model [1] which captures the smooth node speed (V) transition and the radio channel variations in a small time-scale. We show that the PDF of link lifetime in MANETs can be effectively approximated by the exponential distribution characterized by the parameter V/Re. Moreover, we find that the impacting factors on residual link lifetime are in the decreasing order of node speed, transmission range, node-pair distance. The analytical results are validated by extensive simulations. I.
