[[alternative]]A Smart Guiding, Pre-Warning, and Monitoring Wireless Network System for the Blind(I)

計畫編號：NSC93-2745-E032-005-URD研究期間：200408~200507研究經費：822,000[[sponsorship]]行政院國家科學委員

Randomized Initialization of a Wireless Multihop Network

Address autoconfiguration is an important mechanism required to set the IP address of a node automatically in a wireless network. The address autoconfiguration, also known as initialization or naming, consists to give a unique identifier ranging from 1 to $n$ for a set of $n$ indistinguishable nodes. We consider a wireless network where $n$ nodes (processors) are randomly thrown in a square $X$, uniformly and independently. We assume that the network is synchronous and two nodes are able to communicate if they are within distance at most of $r$ of each other ($r$ is the transmitting/receiving range). The model of this paper concerns nodes without the collision detection ability: if two or more neighbors of a processor $u$ transmit concurrently at the same time, then $u$ would not receive either messages. We suppose also that nodes know neither the topology of the network nor the number of nodes in the network. Moreover, they start indistinguishable, anonymous and unnamed. Under this extremal scenario, we design and analyze a fully distributed protocol to achieve the initialization task for a wireless multihop network of $n$ nodes uniformly scattered in a square $X$. We show how the transmitting range of the deployed stations can affect the typical characteristics such as the degrees and the diameter of the network. By allowing the nodes to transmit at a range r= \sqrt{\frac{(1+\ell) \ln{n} \SIZE}{\pi n}} (slightly greater than the one required to have a connected network), we show how to design a randomized protocol running in expected time $O(n^{3/2} \log^2{n})$ in order to assign a unique number ranging from 1 to $n$ to each of the $n$ participating nodes

Optimal Initialization and Gossiping Algorithms for Random Radio Networks

The initialization problem, also known as naming, consists to give a unique identifier ranging from $1$ to $n$ to a set of $n$ indistinguishable nodes in a given network. We consider a network where $n$ nodes (processors) are randomly deployed in a square (resp. cube) $X$. We assume that the time is slotted and the network is synchronous, two nodes are able to communicate if they are within distance at most of $r$ of each other ($r$ is the transmitting/receiving range). Moreover, if two or more neighbors of a processor $u$ transmit concurrently at the same time slot, then $u$ would not receive either messages. We suppose also that the anonymous nodes know neither the topology of the network nor the number of nodes in the network. Under this extremal scenario, we first show how the transmitting range of the deployed processors affects the typical characteristics of the network. Then, by allowing the nodes to transmit at various ranges we design sub-linear randomized initialization protocols~: In the two, resp. three, dimensional case, our randomized initialization algorithms run in $O(n^{1/2} \log{n}^{1/2})$, resp. $O(n^{1/3} \log{n}^{2/3})$, time slots. These latter protocols are based upon an optimal gossiping algorithm which is of independent interest

Random Geometric Graphs and the Initialization Problem for Wireless Networks

32 pages. Tutorial invitéInternational audienceThe initialization problem, also known as naming, assigns one unique identifier (ranging from 1 to $n$) to a set of n indistinguishable nodes (stations or processors) in a given wireless network $N$. $N$ is composed of $n$ nodes randomly deployed within a square (or a cube) $X$. We assume the time to be slotted and $N$ to be synchronous; two nodes are able to communicate if they are within a distance at most $r$ of each other ($r$ is the transmitting/receiving range). Moreover, if two or more neighbors of a processor $u$ transmit concurrently at the same round, $u$ does not receive either messages. After the analysis of various critical transmitting/sensing ranges for connectivity and coverage of randomly deployed sensor networks, we design sub-linear randomized initialization and gossip algorithms achieving $O(n^1/2 \log(n)^1/2)$ and $O(n^1/3 \log(n)^2/3) rounds in the two-dimensional and the three-dimensional cases, respectively. Next, we propose energy-efficient initialization and gossip algorithms running in$O(n^3/4 \log (n)^1/4)$rounds, with no station being awake for more than O(n^1/4 \log (n)^3/4)$ rounds

Adaptive multi-code assignment for a DS-CDMA ad hoc network

Master'sMASTER OF ENGINEERIN

Randomized Initialization Protocols for Ad Hoc Networks

AbstractÐAd hoc networks are self-organizing entities that are deployed on demand in support of various events including collaborative computing, multimedia classroom, disaster-relief, search-and-rescue, interactive mission planning, and law enforcement operations. One of the fundamental tasks that have to be addressed when setting up an ad hoc network (AHN, for short) is initialization. This involves assigning each of the n stations in the AHN a distinct ID number (e.g., a local IP address) in the range from 1 to n. Our main contribution is to propose efficient randomized initialization protocols for AHNs. We begin by showing that if the number 1 n of stations is known beforehand, an n-station, single-channel AHN can be initialized with probability exceeding 1 n,inen‡ p O … n log n† time slots, regardless of whether the AHN has collision detection capability. We then go on to show that even if n is not 1 known in advance, an n-station, single-channel AHN with collision detection can be initialized with probability exceeding 1 n,i

Efficient Passive Clustering and Gateways selection MANETs

Passive clustering does not employ control packets to collect topological information in ad hoc networks. In our proposal, we avoid making frequent changes in cluster architecture due to repeated election and re-election of cluster heads and gateways. Our primary objective has been to make Passive Clustering more practical by employing optimal number of gateways and reduce the number of rebroadcast packets