225 research outputs found
Firefly-inspired Heartbeat Synchronization in Overlay Networks
Heartbeat synchronization strives to have nodes in a
distributed system generate periodic, local “heartbeat”
events approximately at the same time. Many useful distributed protocols rely on the existence of such heart-beats for driving their cycle-based execution. Yet, solving the problem in environments where nodes are unreliable and messages are subject to delays and failures
is non-trivial. We present a heartbeat synchronization
protocol for overlay networks inspired by mathematical models of flash synchronization in certain species of
fireflies. In our protocol, nodes send flash messages to
their neighbors when a local heartbeat triggers. They
adjust the phase of their next heartbeat based on incoming flash messages using an algorithm inspired by
mathematical models of firefly synchronization. We report simulation results of the protocol in various realistic failure scenarios typical in overlay networks and
show that synchronization emerges even when messages
can have significant delay subject to large jitter
E-MAC: an evolutionary solution for collision avoidance in wireless ad hoc networks
Transmission collision is a main cause of throughput degradation and non-deterministic latency in wireless networks. Existing collision-avoidance mechanisms for distributed wireless networks are mostly based on the random backoff strategy, which cannot guarantee collision-free accesses. In this paper, we design a simple collision-avoidance MAC (E-MAC) for distributed wireless networks that can iteratively achieve collision-free access. In E-MAC, each transmitter will adjust its next transmission time according to which part of its packets suffering from the collision. And the iteration of this adjustment will quickly lead group of nodes converging to a collision-free network. E-MAC does not require any central coordination or global time synchronization. It is scalable to new entrants to the network and variable packet lengths. And it is also robust to system errors, such as inaccurate timing.Transmission collision is a main cause of throughput degradation and non-deterministic latency in wireless networks. Existing collision-avoidance mechanisms for distributed wireless networks are mostly based on the random backoff strategy, which cannot guarantee collision-free accesses. In this paper, we design a simple collision-avoidance MAC (E-MAC) for distributed wireless networks that can iteratively achieve collision-free access. In E-MAC, each transmitter will adjust its next transmission time according to which part of its packets suffering from the collision. And the iteration of this adjustment will quickly lead group of nodes converging to a collision-free network. E-MAC does not require any central coordination or global time synchronization. It is scalable to new entrants to the network and variable packet lengths. And it is also robust to system errors, such as inaccurate timing
Formal Verification of Synchronisation, Gossip and Environmental Effects for Wireless Sensor Networks
The Internet of Things (IoT) promises a revolution in the monitoring and control of a wide range of applications, from urban water supply networks and precision agriculture food production, to vehicle connectivity and healthcare monitoring. For applications in such critical areas, control software and protocols for IoT systems must be verified to be both robust and reliable. Two of the largest obstacles to robustness and reliability in IoT systems are effects on the hardware caused by environmental conditions, and the choice of parameters used by the protocol. In this paper we use probabilistic model checking to verify that a synchronisation and dissemination protocol for Wireless Sensor Networks (WSNs) is correct with respect to its requirements, and is not adversely affected by the environment. We show how the protocol can be converted into a logical model and then analysed using the probabilistic model-checker, PRISM. Using this approach we prove under which circumstances the protocol is guaranteed to synchronise all nodes and disseminate new information to all nodes. We also examine the bounds on synchronisation as the environment changes the performance of the hardware clock, and investigate the scalability constraints of this approach
Formal verification of synchronisation, gossip and environmental effects for wireless sensor networks
The Internet of Things (IoT) promises a revolution in the monitoring and control of a wide range of applications, from urban water supply networks and precision agriculture food production, to vehicle connectivity and healthcare monitoring. For applications in such critical areas, control software and protocols for IoT systems must be verified to be both robust and reliable. Two of the largest obstacles to robustness and reliability in IoT systems are effects on the hardware caused by environmental conditions, and the choice of parameters used by the protocol. In this paper we use probabilistic model checking to verify that a synchronisation and dissemination protocol for Wireless Sensor Networks (WSNs) is correct with respect to its requirements, and is not adversely affected by the environment. We show how the protocol can be converted into a logical model and then analysed using the probabilistic model-checker, PRISM. Using this approach we prove under which circumstances the protocol is guaranteed to synchronise all nodes and disseminate new information to all nodes. We also examine the bounds on synchronisation as the environment changes the performance of the hardware clock, and investigate the scalability constraints of this approach. © 2019 Universitatsbibliothek TU Berlin
Bio-Inspired Tools for a Distributed Wireless Sensor Network Operating System
The problem which I address in this thesis is to find a way to organise and manage a network
of wireless sensor nodes using a minimal amount of communication. To find a solution I explore
the use of Bio-inspired protocols to enable WSN management while maintaining a low
communication overhead. Wireless Sensor Networks (WSNs) are loosely coupled distributed
systems comprised of low-resource, battery powered sensor nodes. The largest problem with
WSN management is that communication is the largest consumer of a sensor node’s energy.
WSN management systems need to use as little communication as possible to prolong their operational
lifetimes. This is the Wireless Sensor Network Management Problem. This problem
is compounded because current WSN management systems glue together unrelated protocols
to provide system services causing inter-protocol interference. Bio-inspired protocols provide a
good solution because they enable the nodes to self-organise, use local area communication, and
can combine their communication in an intelligent way with minimal increase in communication.
I present a combined protocol and MAC scheduler to enable multiple service protocols to
function in a WSN at the same time without causing inter-protocol interference. The scheduler
is throughput optimal as long as the communication requirements of all of the protocols remain
within the communication capacity of the network. I show that the scheduler improves a dissemination
protocol’s performance by 35%. A bio-inspired synchronisation service is presented
which enables wireless sensor nodes to self organise and provide a time service. Evaluation of
the protocol shows an 80% saving in communication over similar bio-inspired synchronisation
approaches. I then add an information dissemination protocol, without significantly increasing
communication. This is achieved through the ability of our bio-inspired algorithms to combine
their communication in an intelligent way so that they are able to offer multiple services
without requiring a great deal of inter-node communication.Open Acces
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