Ahmed Jedda

Bluetooth scatternet formation from a time-efficiency perspective

The Bluetooth Scatternet Formation (BSF) problem consists of interconnecting piconets in order to form a multi-hop topology. While a large number of BSF algorithms have been proposed, only few address time as a key parameter, and when doing so, virtually none of the solutions were tested under realistic settings. In particular, the baseband and link layers of Bluetooth are highly specific and known to have crucial impacts on performance. In this paper, we revisit performance studies for a number of time-efficient BSF algorithms, focusing on BlueStars, BlueMesh, and BlueMIS. We also introduce a novel time-efficient BSF algorithm called BSF-UED (for BSF based on Unnecessary-Edges Deletion), which forms connected scatternets deterministically and limits the outdegree of nodes to 7 heuristically. The performance of the algorithm is evaluated through detailed simulation experiments that take into account the low-level specificities of Bluetooth. We show that BSF-UED compares favorably against BlueMesh while requiring only 1/3 of its execution time. Only BlueStars is faster than BSF-UED, but at the cost of a very large number of slaves per master (much more than 7), which makes it impractical in many scenarios.

Decentralized RFID Coverage Algorithms With Applications for the Reader Collisions Avoidance Problem

We aim in this paper at eliminating data and reader redundancies in Radio Frequency Identification (RFID) reader networks. These redundancies have negative impact on the performance of an RFID reader network and in analyzing the readings of the network. We meet our objectives by introducing decentralized RFID coverage [reader collision avoidance (RCA)] algorithm. The RFID coverage problem consists of two subproblems: 1) the tag reporting problem, which aims at assigning to each tag in the network a reader responsible for reporting its data and 2) the redundant readers elimination problem, which aims at minimizing the number of readers in the network while preserving the tags coverage. We introduce two deterministic decentralized RFID coverage algorithms called orientation-based coverage and iterated orientation-based coverage (IOB-COVERAGE). The first algorithm runs in one communication round, whereas the latter runs in O(n) rounds, where n is the number of readers in the network. These algorithms are the first decentralized RFID coverage algorithms that use reader-to-reader communications only. We later introduce an algorithm that solves the RCA algorithm, called IOB-(RCA+COV). The algorithm is a minor modification of IOB-COVERAGE. We formally prove the correctness of our algorithms, and we use detailed simulation experiments to study their performance.

Time-efficient algorithms for the outdegree limited bluetooth scatternet formation problem

We present in this paper three Bluetooth Scatternet Formation (BSF) algorithms which forms deterministically connected and outdegree limited scatternets. Our algorithms improve the execution time of algorithm BlueMIS, which consists of two consecutive phases called BlueMIS I and BlueMIS II. The first phase, BlueMIS I, is a BSF algorithm that forms connected and outdegree limited scatternets in a time-efficient manner. Our algorithms improve BlueMIS by improving BlueMIS I. First, we introduce a time-efficient implementation of communication rounds, called OrderedExchange, that is more suitable for Bluetooth networks, where in a communication round each node sends and receives a message to and from all its neighbors. Using OrderedExchange, we introduce algorithms ComputeMIS I and ComputeMIS II which form the same scatternet as those formed by BlueMIS I but with less execution time. We also introduce algorithm Eliminate. Instead of letting each node u forms a maximal independent set of all its neighbors and then considers them as slaves, as in the case of BlueMIS I, Eliminate let each node u forms a maximal independent set of all its neighbors that have smaller identifiers. Eliminate forms scatternets that are similiar to those formed by BlueMIS I, and more efficient with respect to some performance metrics. Eliminate improves the execution time of ComputeMIS I and ComputeMIS II by about 60%.

Forming MS-Free and Outdegree-Limited Bluetooth Scatternets in Pessimistic Environments

This paper introduces two distributed Bluetooth scatternet formation (BSF) algorithms, called

Decentralized RFID coverage algorithms using writeable tags

\mathtt{BSFWAVVY(MSF)}

Forming MS-free and outdegree-limited Bluetooth scatternets in pessimistic environments

and

BSF-UED: A new time-efficient Bluetooth Scatternet Formation algorithm based on Unnecessary-Edges Deletion

\mathtt{BSFWAVVY(ODL)}

Connected Coverage for RFID and Wireless Sensor Networks

. The first algorithm forms scatternets that does not contain master–slave (MS) bridges (MS-free scatternets), whereas the second algorithm forms scatternets in which each piconet has at most

Enhancing DHT-based object naming service architectures with geographic-awareness

k

Some side effects of FHSS on Bluetooth networks distributed algorithms

slaves (outdegree-limited scatternets). The motivation is that MS-freeness and outdegree limitation are the two properties that significantly improve the quality of the scatternets. However, and contrary to the existing BSF algorithms, our algorithms consider these properties under pessimistic environments modeled as arbitrary networks (i.e., no assumptions are made on the underlying network topology). We give two lower bounds that prove the asymptotic optimality of our algorithms with respect to time complexity and message complexity. We also show that the problem of forming MS-free and outdegree-limited scatternets at the same time is