Search results for "802.11"

Analysis of the efficacy of a WiFi architecture for the management of medium voltage distribution systems

2010

The paper illustrates the interventions for improving security of a WiFi communication system applied in the automatic management of a Medium Voltage network. The management system fails if the data measured at the secondary substations can’t flow regularly. In this paper the security of the transmission as function of the action range of the radio channel, on the data sending time of the IEEE 802.11 protocol, and of the out of use of a WiFi node. Then, a modified IEEE 802.11 protocol is described, for making secure the transmission in presence of a high number of WiFI nodes. Finally, a probabilistic analysis in presented for analyzing the problem from an economical point of view.

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…

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…

FPGA Implementation of a Reconfigurable 802.11 Medium Access Control

THis work describes a full implementation of a reconfigurable IEEE 802.11 Medium Access Control (MAC) in FPGA using a System on Chip (SoC) architecture. The proposed implementation has been designed with a great structural flexibility, so to ease the protocol modification, and to support Quality of Service (QoS) function. Estensive tests has been carried out showing a full compliance to the 802.11 standard timing and algorithms.

MAC–Engine: a new architecture for executing MAC algorithms on commodity WiFi hardware

2011

In this demo, we prove that the flexibility supported by off–the–shelf IEEE 802.11 hardware can be significantly ex- tended if we move the control of the MAC programming interface from the driver to the firmware, i.e. from the host CPU to the card CPU. To this purpose, we introduce the concept of MAC–Engine, that is an executor of Pro- grammable Finite State Machines (PFSM) implemented at the firmware level: we show how the card itself can support different protocol logics thanks to PFSM bytecode repre- sentations that can be dynamically injected inside the card memory at run-time without incurring in down time issues or network disconnect events. We provide different PFSM examples in order…

Achieving Robustness through Caching and Retransmissions in IEEE 802.15.4-based WSNs

2007

This paper proposes a network-layer protocol for wireless sensor networks based on the IEEE 802.15.4 standard. Our protocol is devised to provide reliable data gathering in latency-constrained applications, and exploits both the flexibility of the IEEE 802.15.4 MAC layer and features of data aggregation techniques, such as implicit acknowledgment of reception. The proposed protocol acts as a routing module and a control entity for the MAC layer and provides reliable communication, while managing power saving and synchronizertion among nodes. Without relying on MAC-layer acknowledgments, the protocol implements caching and network-layer retransmissions, triggered upon detection of a link fai…

SHARP: Environment and Person Independent Activity Recognition with Commodity IEEE 802.11 Access Points

2022

In this article we present SHARP, an original approach for obtaining human activity recognition (HAR) through the use of commercial IEEE 802.11 (Wi-Fi) devices. SHARP grants the possibility to discern the activities of different persons, across different time-spans and environments. To achieve this, we devise a new technique to clean and process the channel frequency response (CFR) phase of the Wi-Fi channel, obtaining an estimate of the Doppler shift at a radio monitor device. The Doppler shift reveals the presence of moving scatterers in the environment, while not being affected by (environment-specific) static objects. SHARP is trained on data collected as a person performs seven differe…

On the Fidelity of IEEE 802.11 commercial cards

2006

The IEEE 802.11 D CF protocol is known to be fair in terms of long-term resource repartition among the contending stations. However, when considering real scenarios, where commercial 802.11 cards interact, very unpredictable as well as sometimes surprising behaviors emerge. Motivation of this paper is to investigate the reasons of the very evident disagreement between the theoretical IEEE 802.11 DCF protocol models and its practical implementations. Inparticular, we try to characterize the card behavior not only in terms of perceived throughput, but also in terms of low-level channel access operations. In fact, the simple throughput analysis does not allow to identify what affecting paramet…

A Software Defined Radio Platform Implementing a WiFi and ZigBee Receiver

2006

A successful attempt to design and implement a multi-standard compliant Basebnd Processor is here presented. By exploiting the potential of FPGA's reconfigurability, the received signal from RF stage have been processed in order to properly decode frames of IEEE 802.11 (WiFi) and IEEE 802.15.4 (ZigBee) protocols. both falling within the ISM band (centered at 2.45GHz). The experimental implementation carried out is a practical demonstration of the Software Defined Radio concept.

One size hardly fits all

2013

This paper casts recent accomplishments in the field of Wireless MAC programmability into the emerging Software Defined Networking perspective. We argue that an abstract (but formal) description of the MAC protocol logic in terms of extensible finite state machines appears a convenient and viable data-plane programming compromise for modeling and deploying realistic MAC protocol logics. Our approach is shown to comply with existing control frameworks, and entails the ability to dynamically change the MAC protocol operation based on context and scenario conditions; in essence, move from the traditional idea of "one-size-fits-all" MAC protocol stack to the innovative paradigm of opportunistic…