10 research outputs found
Constructive Interference in 802.15.4: A Tutorial
International audienceConstructive Interference (CI) can happen when multiple wireless devices send the same frame at the same time. If the time offset between the transmissions is less than 500 ns, a receiver will successfully decode the frame with high probability. CI can be useful for achieving low-latency communication or low-overhead flooding in a multi-hop low-power wireless network. The contribution of this article is threefold. First, we present the current state-of-the-art CI-based protocols. Second, we provide a detailed hands-on tutorial on how to implement CI-based protocols on TelosB motes, with well documented open-source code. Third, we discuss the issues and challenges of CI-based protocols, and list open issues and research directions. This article is targeted at the level of practicing engineers and advanced researchers and can serve both as a primer on CI technology and a reference to its implementation
Atomic-SDN: Is Synchronous Flooding the Solution to Software-Defined Networking in IoT?
The adoption of Software Defined Networking (SDN) within traditional networks
has provided operators the ability to manage diverse resources and easily
reconfigure networks as requirements change. Recent research has extended this
concept to IEEE 802.15.4 low-power wireless networks, which form a key
component of the Internet of Things (IoT). However, the multiple traffic
patterns necessary for SDN control makes it difficult to apply this approach to
these highly challenging environments. This paper presents Atomic-SDN, a highly
reliable and low-latency solution for SDN in low-power wireless. Atomic-SDN
introduces a novel Synchronous Flooding (SF) architecture capable of
dynamically configuring SF protocols to satisfy complex SDN control
requirements, and draws from the authors' previous experiences in the IEEE EWSN
Dependability Competition: where SF solutions have consistently outperformed
other entries. Using this approach, Atomic-SDN presents considerable
performance gains over other SDN implementations for low-power IoT networks. We
evaluate Atomic-SDN through simulation and experimentation, and show how
utilizing SF techniques provides latency and reliability guarantees to SDN
control operations as the local mesh scales. We compare Atomic-SDN against
other SDN implementations based on the IEEE 802.15.4 network stack, and
establish that Atomic-SDN improves SDN control by orders-of-magnitude across
latency, reliability, and energy-efficiency metrics
Opportunistic Routing and Synchronous Transmissions Meet TSCH
Low-power wireless networking commonly uses either Time-Slotted Channel Hopping (TSCH), synchronous transmissions, or opportunistic routing. All three of these different, orthogonal approaches strive for efficient and reliable communication but follow different trajectories. With this paper, we combine these concepts into one protocol: AUTOBAHN.AUTOBAHN merges TSCH scheduling with opportunistically routed, synchronous transmissions. This opens the possibility to create long-term stable schedules overcoming local interference. We prove the stability of schedules over several days in our experimental evaluation. Moreover, AUTOBAHN outperforms the autonomous scheduler Orchestra under interference in terms of reliability by 13.9 percentage points and in terms of latency by a factor of 9 under a minor duty cycle increase of 2.1 percentage points
Synchronous Transmissions in Low-Power Wireless: A Survey of Communication Protocols and Network Services
Low-power wireless communication is a central building block of
Cyber-physical Systems and the Internet of Things. Conventional low-power
wireless protocols make avoiding packet collisions a cornerstone design choice.
The concept of synchronous transmissions challenges this view. As collisions
are not necessarily destructive, under specific circumstances, commodity
low-power wireless radios are often able to receive useful information even in
the presence of superimposed signals from different transmitters. We survey the
growing number of protocols that exploit synchronous transmissions for higher
robustness and efficiency as well as unprecedented functionality and
versatility compared to conventional designs. The illustration of protocols
based on synchronous transmissions is cast in a conceptional framework we
establish, with the goal of highlighting differences and similarities among the
proposed solutions. We conclude the paper with a discussion on open research
questions in this field.Comment: Submitted to ACM Computing Survey
Estudio y modificación de una cinta de fitness
El centro comarcal ocupacional ADISPAZ alza la inquietud acerca de la posibilidad de devolver al servicio una de las cintas ergométricas que utilizan para brindarcinesioterapia de la marcha y otras actividades deportivas.Se emplea un método de trabajo iterativo para analizar la cuestión y llevar a cabo un desarrollo con diferentes fases en función de los distintos condicionantes que se presentanSe observa que el uso de un método objetivo permite la consecución de buenas aproximaciones a objetivos en condiciones variables. El modelo en V proporciona un marco de trabajo que propicia la mejora continua en los resultados, fomentando la iteración de procesos de desarrollo técnico.También se sientan las bases para futuras lÃneas de trabajo. Incitando a llevar a cabo actividades posteriores similares, para que asà continúe el proceso de estudio cientÃfico y desarrollo técnico, en esta y otras materias.<br /