2,136 research outputs found
Lightweight Synchronization Algorithm with Self-Calibration for Industrial LORA Sensor Networks
Wireless sensor and actuator networks are gaining momentum in the era of
Industrial Internet of Things IIoT. The usage of the close-loop data from
sensors in the manufacturing chain is extending the common monitoring scenario
of the Wireless Sensors Networks WSN where data were just logged. In this paper
we present an accurate timing synchronization for TDMA implemented on the state
of art IoT radio, such as LoRa, that is a good solution in industrial
environments for its high robustness. Experimental results show how it is
possible to modulate the drift correction and keep the synchronization error
within the requirements
Synchronization of multihop wireless sensor networks at the application layer
Time synchronization is a key issue in wireless
sensor networks; timestamping collected
data, tasks scheduling, and efficient communications
are just some applications. From all the
existing techniques to achieve synchronization,
those based on precisely time-stamping sync
messages are the most accurate. However, working
with standard protocols such as Bluetooth or
ZigBee usually prevents the user from accessing
lower layers and consequently reduces accuracy.
A receiver-to-receiver schema improves timestamping
performance because it eliminates the
largest non-deterministic error at the sender’s
side: the medium access time. Nevertheless, utilization
of existing methods in multihop networks
is not feasible since the amount of extra
traffic required is excessive. In this article, we
present a method that allows accurate synchronization
of large multihop networks, working at
the application layer while keeping the message
exchange to a minimum. Through an extensive
experimental study, we evaluate the protocol’s
performance and discuss the factors that influence
synchronization accuracy the most.Ministerio de Ciencia y Tecnología TIN2006-15617-C0
Enhanced Precision Time Synchronization for Wireless Sensor Networks
Time synchronization in wireless sensor networks (WSNs) is a fundamental issue for the coordination of distributed entities and events. Nondeterministic latency, which may decrease the accuracy and precision of time synchronization can occur at any point in the network layers. Specially, random back-off by channel contention leads to a large uncertainty. In order to reduce the large nondeterministic uncertainty from channel contention, we propose an enhanced precision time synchronization protocol in this paper. The proposed method reduces the traffic needed for the synchronization procedure by selectively forwarding the packet. Furthermore, the time difference between sensor nodes increases as time advances because of the use of a clock source with a cheap crystal oscillator. In addition, we provide a means to maintain accurate time by adopting hardware-assisted time stamp and drift correction. Experiments are conducted to evaluate the performance of the proposed method, for which sensor nodes are designed and implemented. According to the evaluation results, the performance of the proposed method is better than that of a traditional time synchronization protocol
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