146 research outputs found
Efficient GTS Allocation Schemes for IEEE 802.15.4
IEEE 802.15.4 is a standard defined for wireless sensor network applications with limited power and relaxed throughput needs. The devices transmit data during two periods: Contention Access Period (CAP) by accessing the channel using CSMA/CA and Contention Free Period (CFP), which consists of Guaranteed Time Slots (GTS) allocated to individual devices by the network coordinator. The GTS is used by devices for cyclic data transmission and the coordinator can allocate GTS to a maximum of only seven devices. In this work, we have proposed two algorithms for an efficient GTS allocation. The first algorithm is focused on improving the bandwidth utilization of devices, while the second algorithm uses traffic arrival information of devices to allow sharing of GTS slots between more than seven devices. The proposed schemes were tested through simulations and the results show that the new GTS allocation schemes perform better than the original IEEE 802.15.4 standard
A Beacon and GTS Scheduling Scheme for IEEE 802.15.4 DSME Networks
[EN] The IEEE 802.15.4 standard is one of the widely adopted networking specification for realizing different applications of Internet of Things (IoT). It defines several physical layer options and medium access control (MAC) sublayer protocols for low-power devices supporting low-data rates. One such MAC protocol is the deterministic and synchronous multichannel extension (DSME), which addresses the limitation on the maximum number of guaranteed time slots (GTSs) in 802.15.4-2011 MAC, and provides channel diversity to increase network robustness. However, beacon scheduling in peer-to-peer networks suffers from beacon slot collisions when two or more coordinators simultaneously compete for the same vacant beacon slot. In addition, the standard does not explore DSME-GTS scheduling (DGS) across multiple channels. This article addresses the beacon slot collision problem by proposing a nonconflicting beacon scheduling mechanism using association order (AO). Furthermore, a distributed multichannel DSME-GTS schedule is proposed that optimally assigns DSME-GTSs across different channels. The objective is to minimize the number of times-lots used while maximizing the usage of available channels. Through simulations, the proposed mechanisms' performance is analyzed in terms of energy efficiency, transmission overhead, scheduling efficiency, throughput, and latency and is shown to outperform the other existing schemes.Choudhury, N.; Matam, R.; Mukherjee, M.; Lloret, J. (2022). A Beacon and GTS Scheduling Scheme for IEEE 802.15.4 DSME Networks. IEEE Internet of Things. 9(7):5162-5172. https://doi.org/10.1109/JIOT.2021.3110866516251729
MAC protocols for low-latency and energy-efficient WSN applications
Most of medium access control (MAC) protocols proposed for wireless sensor
networks (WSN) are targeted only for single main objective, the energy
efficiency. Other critical parameters such as low-latency, adaptivity to
traffic conditions, scalability, system fairness, and bandwidth utilization
are mostly overleaped or dealt as secondary objectives. The demand to address
those issues increases with the growing interest in cheap, low-power, low-
distance, and embedded WSNs. In this report, along with other vital
parameters, we discuss suitability and limitations of different WSN MAC
protocols for time critical and energy-efficient applications. As an example,
we discuss the working of IEEE 802.15.4 in detail, explore its limitations,
and derive efficient application-specific network parameter settings for time,
energy, and bandwidth critical applications. Eventually, a new WSN MAC
protocol Asynchronous Real-time Energy-efficient and Adaptive MAC (AREA-MAC)
is proposed, which is intended to deal efficiently with time critical
applications, and at the same time, to provide a better trade-off between
other vital parameters, such as energy-efficiency, system fairness,
throughput, scalability, and adaptivity to traffic conditions. On the other
hand, two different optimization problems have been formulated using
application-based traffic generating scenario to minimize network latency and
maximize its lifetime
Smart guaranteed time-slot allocation algorithm for industrial wireless sensor networks emergency message transmission
This paper is a postprint of a paper submitted to and accepted for publication in IET Wireless Sensor Systems and is subject to Institution of Engineering and Technology Copyright. The copy of record is available at IET Digital LibraryThis paper presents investigation on application of wireless sensor networks (WSNs) in wind power generation systems and highlights an important issue associated with the deadline for the delivery of messages among nodes based on the IEEE 802.15.4E standard. Owing to the limits of standard and the power system application requirements, this research proposes a smart guaranteed time slot (S-GTS) allocation algorithm which is based on the urgent/important matrix. This proposed algorithm promotes the utilisation of contention free period in a superframe. Besides, over seven GTSs can be allocated in a superframe, there are only seven GTSs that can be used in the standard. In addition, this study proves the value of BO and SO upper bound is 6 for the WSN application in power systems. Moreover, the network delay of S-GTS performs better than the 16-time-slot mechanism and i-GAME mechanism
A Performance-to-Cost Analysis of IEEE 802.15.4 MAC With 802.15.4e MAC Modes
[EN] The IEEE 802.15.4 standard is one of the widely adopted networking specification for Internet of Things (IoT). It defines several physical layer (PHY) options and medium access control (MAC) sub-layer protocols for interconnection of constrained wireless devices. These devices are usually battery-powered and need to support requirements like low-power consumption and low-data rates. The standard has been revised twice to incorporate new PHY layers and improvements learned from implementations. Research in this direction has been primarily centered around improving the energy consumption of devices. Recently, to meet specific Quality-of-Service (QoS) requirements of different industrial applications, the IEEE 802.15.4e amendment was released that focuses on improving reliability, robustness and latency. In this paper, we carry out a performance-to-cost analysis of Deterministic and Synchronous Multi-channel Extension (DSME) and Time-slotted Channel Hopping (TSCH) MAC modes of IEEE 802.15.4e with 802.15.4 MAC protocol to analyze the trade-off of choosing a particular MAC mode over others. The parameters considered for performance are throughput and latency, and the cost is quantified in terms of energy. A Markov model has been developed for TSCH MAC mode to compare its energy costs with 802.15.4 MAC. Finally, we present the applicability of different MAC modes to different application scenarios.This work was supported in part by the SERB, DST, Government of India under Grant ECRA/2016/001651.Choudhury, N.; Matam, R.; Mukherjee, M.; Lloret, J. (2020). A Performance-to-Cost Analysis of IEEE 802.15.4 MAC With 802.15.4e MAC Modes. IEEE Access. 8:41936-41950. https://doi.org/10.1109/ACCESS.2020.2976654S4193641950
Data Transmission with Reduced Delay for Distributed Acoustic Sensors
This paper proposes a channel access control scheme fit to dense acoustic
sensor nodes in a sensor network. In the considered scenario, multiple acoustic
sensor nodes within communication range of a cluster head are grouped into
clusters. Acoustic sensor nodes in a cluster detect acoustic signals and
convert them into electric signals (packets). Detection by acoustic sensors can
be executed periodically or randomly and random detection by acoustic sensors
is event driven. As a result, each acoustic sensor generates their packets
(50bytes each) periodically or randomly over short time intervals
(400ms~4seconds) and transmits directly to a cluster head (coordinator node).
Our approach proposes to use a slotted carrier sense multiple access. All
acoustic sensor nodes in a cluster are allocated to time slots and the number
of allocated sensor nodes to each time slot is uniform. All sensor nodes
allocated to a time slot listen for packet transmission from the beginning of
the time slot for a duration proportional to their priority. The first node
that detect the channel to be free for its whole window is allowed to transmit.
The order of packet transmissions with the acoustic sensor nodes in the time
slot is autonomously adjusted according to the history of packet transmissions
in the time slot. In simulations, performances of the proposed scheme are
demonstrated by the comparisons with other low rate wireless channel access
schemes.Comment: Accepted to IJDSN, final preprinted versio
DynaMO—Dynamic Multisuperframe Tuning for Adaptive IEEE 802.15.4e DSME Networks
Recent advancements in the IoT domain have been pushing for stronger demands of Qualityof-Service (QoS) and in particular for improved determinism for time-critical wireless communications
under power constraints. The IEEE 802.15.4e standard protocol introduced several new MAC behaviors that
provide enhanced time-critical and reliable communications. The Deterministic Synchronous Multichannel
Extension (DSME) is one of its prominent MAC behaviors that combines contention-based and contentionfree communication, guaranteeing bounded delays and improved reliability and scalability by leveraging
multi-channel access and CAP reduction. However, DSME has a multi-superframe structure, which is
statically defined at the beginning of the network. As the network evolves dynamically by changing its traffic
characteristics, these static settings can affect the overall throughput and increase the network delay because
of improper allocation of bandwidth. In this paper, we address this problem, and we present a dynamic
multi-superframe tuning technique that dynamically adapts the multi-superframe structure based on the size
of the network. This technique improves the QoS by providing 15-30% increase in throughput and 15-35%
decrease in delay when compared to static DSME networksinfo:eu-repo/semantics/publishedVersio
Dimensioning and worst-case analysis of cluster-tree sensor networks
Modeling the fundamental performance limits of Wireless Sensor Networks (WSNs) is of paramount
importance to understand their behavior under the worst-case conditions and to make the appropriate
design choices. This is particular relevant for time-sensitive WSN applications, where the
timing behavior of the network protocols (message transmission must respect deadlines) impacts
on the correct operation of these applications. In that direction this paper contributes with a
methodology based on Network Calculus, which enables quick and efficient worst-case dimensioning
of static or even dynamically changing cluster-tree WSNs where the data sink can either
be static or mobile. We propose closed-form recurrent expressions for computing the worst-case
end-to-end delays, buffering and bandwidth requirements across any source-destination path in a
cluster-tree WSN. We show how to apply our methodology to the case of IEEE 802.15.4/ZigBee
cluster-tree WSNs. Finally, we demonstrate the validity and analyze the accuracy of our methodology
through a comprehensive experimental study using commercially available technology, namely
TelosB motes running TinyOS
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