145 research outputs found
An Analysis of Packet Fragmentation Impact in LPWAN
Packet fragmentation has mostly been addressed in the literature when
referring to splitting data that does not fit a frame. It has received
attention in the IoT community after the 6LoWPAN working group of IETF started
studying the fragmentation headers to allow IPv6 1280 B MTU to be sent over
IEEE 802.15.4 networks supporting a 127 B MTU. In this paper, and following
some of the recent directions taken by the IETF LPWAN WG, an analysis of packet
fragmentation in LPWANs has been done. We aim to identify the impact of sending
the data in smaller fragments considering the restrictions of industrial
duty-cycled networks. The analyzed parameters were the energy consumption,
throughput, goodput and end to end delay introduced by fragmentation. The
results of our analysis show that packet fragmentation can increase the
reliability of the communication in duty-cycle restricted networks. This is of
especial relevance when densifying the network. We observed relevant impact in
energy consumption and extra latency, and identified the need for
acknowledgements from the gateway/sink to exploit some of the benefits raised
by fragmentation.Comment: paper accepted and presented at IEEE Wireless Communications and
Networking Conference, 15-18 April, Barcelona, Spai
Aggressive Fragmentation Strategy for Enhanced Network Performance in Dense LPWANs
Low Power Wide Area Networks (LPWANs) are gaining ground in the IoT landscape
and, in particular, for Industrial IoT applications. However, given the strict
duty cycle restrictions (e.g. 1% in SubGHz bands) and the limited power supply
of devices, requirements of some applications can not always be met. This paper
analyzes the potential of the combination of packet fragmentation -in the
direction of the IETF LPWAN working group- and negative group acknowledgement
(NACK) in LoRaWAN networks, a widespread LPWAN technology. Results show that
the proposed strategy can lead to significant gains in terms of goodput and
energy efficiency under congested situations.Comment: 2018 IEEE 29th Annual International Symposium on Personal, Indoor and
Mobile Radio Communications (PIMRC
LoRa Multi-Hop Networks for Monitoring Underground Mining Environments
Internet of Things applications have gained widespread recognition for their
efficacy in typical scenarios, such as smart cities and smart healthcare.
Nonetheless, there exist numerous unconventional situations where IoT
technologies have not yet been massively applied, though they can be extremely
useful. One of such domains is the underground mining sector, where enhancing
automation monitoring through wireless communications is of essential
significance. In this paper, we focus on the development, implementation, and
evaluation of a LoRa-based multi-hop network tailored specifically for
monitoring underground mining environments, where data traffic is sporadic, but
energy efficiency is of paramount importance. We hence define a synchronization
framework that makes it possible for the nodes to sleep for most of the time,
waking up only when they need to exchange traffic. Notably, our network
achieves a sub 40us proven synchronization accuracy between parent-child pairs
with minimum overhead for diverse topologies, rendering it highly viable for
subterranean operations. Furthermore, for proper network dimensioning, we model
the interplay between network's throughput, frame size, and sampling periods of
potential applications. Moreover, we propose a model to estimate devices' duty
cycle based on their position within the multi-hop network, along with
empirical observations for its validation. The proposed models make it possible
to optimize the network's performance to meet the specific demands that can
arise from the different subterranean use cases, in which robustness, low power
operation, and compliance with radio-frequency regulations are key requirements
that must be met
REMOTE, a Wireless Sensor Network Based System to Monitor Rowing Performance
In this paper, we take a hard look at the performance of REMOTE, a sensor network based application that provides a detailed picture of a boat movement, individual rower performance, or his/her performance compared with other crew members. The application analyzes data gathered with a WSN strategically deployed over a boat to obtain information on the boat and oar movements. Functionalities of REMOTE are compared to those of RowX [1] outdoor instrument, a commercial wired sensor instrument designed for similar purposes. This study demonstrates that with smart geometrical configuration of the sensors, rotation and translation of the oars and boat can be obtained. Three different tests are performed: laboratory calibration allows us to become familiar with the accelerometer readings and validate the theory, ergometer tests which help us to set the acquisition parameters, and on boat tests shows the application potential of this technologies in sports
Understanding the limits of LoRaWAN
The quick proliferation of LPWAN networks, being LoRaWAN one of the most
adopted, raised the interest of the industry, network operators and facilitated
the development of novel services based on large scale and simple network
structures. LoRaWAN brings the desired ubiquitous connectivity to enable most
of the outdoor IoT applications and its growth and quick adoption are real
proofs of that. Yet the technology has some limitations that need to be
understood in order to avoid over-use of the technology. In this article we aim
to provide an impartial overview of what are the limitations of such
technology, and in a comprehensive manner bring use case examples to show where
the limits are
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