Search results for " protocol"

An Improved IEEE 802.11 Protocol for Reliable Data Transmission in Power Distribution Fault Diagnosis

2010

A high level of power quality in distribution networks is obtained by means of a diagnostic software, that on-line assesses the status of the network, by elaborating the measured data. An efficient telecommunication system is thus necessary. Upon occurrence of a fault the reliability of the distribution system depends on the security of the timely protective and restorative actions on the network. In this paper, after a brief examination of the diagnostic method, the telecommunication system is examined. For this purpose, the WiFi telecommunication system has been considered the most suitable due to its economy, although it is not adequately reliable for how it is managed by the IEEE 802.11…

Revealing Transmit Diversity Mechanisms in Commercial IEEE 802.11 Cards

2008

Service differentiation in WLAN has been traditionally faced at the MAC layer. However, some PHY layer parameters, such as the transmission power, the antenna, and the modulation/coding scheme, have a deep impact on network performance. Since the criterion for selecting these parameters is left to the vendor specific implementations, the performance spread of most experimental results about 802.11 WLAN could be affected by vendor proprietary schemes. The focus of this paper is an experimental analysis of the undisclosed antenna diversity mechanisms employed by some widely used cards (namely, the Atheros and Intel based cards), and a thorough understanding of the optimization goals which gui…

An energy analysis of IEEE 802.15.6 scheduled access modes

2010

Body Area Networks (BANs) are an emerging area of wireless personal communications. The IEEE 802.15.6 working group aims to develop a communications standard optimised for low power devices operating on, in or around the human body. IEEE 802.15.6 specifically targets low power medical application areas. The IEEE 802.15.6 draft defines two main channel access modes; contention based and contention free. This paper examines the energy lifetime performance of contention free access and in particular of periodic scheduled allocations. This paper presents an overview of the IEEE 802.15.6 and an analytical model for estimating the device lifetime. The analysis determines the maximum device lifeti…

Coexistence between IEEE802.15.4 and IEEE802.11 through cross-technology signaling

2017

When different technologies use the same frequency bands in close proximity, the resulting interference typically results in performance degradation. Coexistence methods exist, but these are often technology specific and requiring technology specific interference detection methods. To remove the root cause of the performance degradation, devices should be able to negotiate medium access even when using different technologies. To this end, this paper proposes an architecture that allows crosstechnology medium access by means of a Time Division Multiple Access (TDMA) scheme. In order to achieve cross-technology synchronization, which is required for the TDMA solution, an energy pattern beacon…

Cross-Technology WiFi/ZigBee Communications: Dealing With Channel Insertions and Deletions

2016

In this letter, we show how cross-technology interference can be exploited to set up a low-rate bidirectional communication channel between heterogeneous WiFi and ZigBee networks. Because of the environment noise and receivers' implementation, the cross-technology channel can be severely affected by insertions and deletions of symbols, whose effects need to be taken into account by the coding scheme and communication protocol.

A study about DDoS attacks in SIP environments

2007

Introduction To Multimedia Sip User Agents

2007

Method of changing the operation of wireless network nodes

2013

Dealing with uncertainty in consensus protocol

2009

Recent results on Consensus protocols for networks are presented. The basic tools and the main contribution available in the literature are considered, together with some of the related challenging aspects: estimation in networks and how to deal with disturbances is considered. Motivated by applications to sensor, peer-to-peer, and ad hoc networks, many papers have considered the problem of estimation in a consensus fashion. Here, the Unknown But Bounded (UBB) noise affecting the network is addressed in details. Because of the presence of UBB disturbances convergence to equilibria with all equal components is, in general, not possible. The solution of the $\epsilon$-consensus problem, where…

Toward a Society of Robots: Behavior, Misbehavior, and Security

2010

In this article, we consider how a very large numbers of robots, differing in their bodies, sensing, and intelligence, may be made to coexist, communicate, and compete fairly toward achieving their individual goals, i.e., to build a society of robots. We discuss some characteristics that the rules defining acceptable social behaviors should possess. We consider threats that may be posed to such a society by the misbehaviors of some of its members, either due to faults or malice, and the possibility to detect and isolate them through cooperation of peers. The article presents examples of motion control protocols, for arbitrarily large groups of heterogeneous robots. We discuss intrusion dete…