Medium Access Control Mechanism Research Articles

Exclusive-Region-Map-Based Medium Access Control in Mobile Networks With Directional Antennas Through Deep Interference Learning

The medium access control (MAC) design in mobile networks with directional antennas is challenging due to the difficulty of defining the exact RF interference range between two neighboring directional links and the frequent changes of interference range due to node mobility. This research targets directional data reception (Rx) and transmission (Tx) coordination issues based on the computation of directional interference ranges from nearby directional links. An innovative MAC mechanism is designed with three features: (1) ER-map, i.e., the spatial expression of exclusive region (ER) model in the format of a heatmap. The ER-map helps to determine the directional interference range in typical communication scenarios. Different ER-map cases are analyzed based on the spatial layout differences for two nearby directional links. (2) Spatio-temporal ER-map evolution prediction: a Spatio-Temporal Residual Network (ST-ResNet+) model is used to describe the spatial correlations (for the ERs among neighboring links) and temporal correlations (for the ERs across different time instants) as well as the ER map evolution patterns. Such a Deep ST-ResNet+ model is used to predict the next-time ER map’s snapshot. (3) Optimized directional MAC protocol based on ER map predictions: The ST-ResNet+ prediction results are used to determine the MAC operations, such as Tx/Rx schedule arrangement in the one-hop area, sending rate adjustments, etc. Comprehensive simulations are conducted to validate the throughput efficiency for the proposed directional MAC scheme.

2DMAC: A Sustainable and Efficient Medium Access Control Mechanism for Future Wireless NoCs

Wireless Network-on-Chip (WNoC) requires a Medium Access Control (MAC) mechanism for an interference-free sharing of the wireless channel. In traditional MAC, a token is circulated among the Wireless Interfaces (WIs) in a Round Robin manner. The WI with the token holds the channel for a fixed number of cycles. However, the channel requirement of the individual WIs dynamically changes over time due to the varying traffic density across the WNoC. Moreover, the conventional WNoCs give equal importance to all the traffic taking the wireless path and transmit it in an oldest-first manner. Nevertheless, the critical data can degrade the system performance to a large extent by delaying the application runtime if not served promptly. We propose 2DMAC, which can change the token arbitration pattern and tune the channel hold time of each WI based on its runtime traffic density and criticality status. Moreover, 2DMAC prioritizes the critical traffic over the non-critical traffic during the wireless data transfer. The proposed mechanism improves the wireless channel utilization by 15.67% and the network throughput by 29.83% and reduces the critical data latency by 29.77% over the traditional MAC.

An effectual spectrum sharing and battery utilization strategy using fuzzy enabled dynamic relay polling transmission in WSN

Power dissipation at the network level to improve lifespan without degrading the bandwidth and collaboration is a fundamental impediment to effective spectral efficiency in wireless sensor networks (WSNs). This issue is made much more difficult. Wireless energy transfer (WET) for energizing remote sensor nodes gained interest. This research explores an FDD-based on-demand scenario with many relays where a transmitter is powered by direct and relayed links. A threshold is set for transmission energy & channel quality to decide whether the broadcasting can be efficient (for spectrum utilization) or the packet would not arrive at its destination. The network model offers an energy-efficient scheduling strategy to decide whether to transmit information or not depending on the stored higher energy and network status. An energy-aware polling-based medium access control (MAC) mechanism, composite energy, and information first (CEDF) has also been developed to fine-tune packet delivery ratio by utilizing datagrams and energy packages to set polling prioritization. Computational simulations indicate that energy relayed and the recommended energy-efficient scheduled technique decrease the system’s active power losses supporting all theoretical predictions.

Development and analysis of new implementations of MAC proto-cols and mobility models in LoRa networks

The technological revolution known as Internet of Things (IoT) brings together several areas of science and technology, such as data acquisition, energy consumption, Wireless Sensor Networks (WSN), data analyses and processing among others. IoT gets its name from the several applications, from wearables to cars connected to the network, spanning the transportation, health, electronics, water, and electricity industries. This massive addition of LoRa devices for its own application brings the problems of a shared medium such as frame collision. Additionally, as the devices are often battery powered there is a need to analyze the battery consumption. It was found that there is a lack of tools to estimate the consumption and performance of a network. In this paper, we implement new medium access control mechanisms for LoRaSim simulator, based on CSMA/CAD (Carrier Sense Multiple Access with Collision Avoidance and Detection). This addition tests the influence a different access protocol has on the LoRa network and its resilience. As part of this study the new access protocol is built on the existing simulator LoRaSim to study the difference between the access protocol currently used in LoRa, an ALOHA protocol variant, CSMA/CA (CSMA with Collision Avoidance) and CSMA/CAD with the purpose of analyzing the difference in collision between protocols and the respective energy consumption in mobility scenarios.

Dynamic Beacon Distribution Mechanism for Internet of Vehicles: An Analytical Study

In the last decade, with the arrival of the 5G communication technology and the increasing numbers of vehicles being connected to the internet, conventional vehicle ad-hoc networks (VANETs) are evolving towards the internet of vehicles (IoV), which makes the co-existence of IEEE 802.11p and 5G-based technologies very important for the design of a heterogeneous IoV system that takes advantage of both. The IEEE 802.11p standard is still the best candidate to support direct communications for safety critical services. In fact, both the ETSI ITS-G5 and the IEEE 1609 standard families adopt the IEEE 802.11p standard as a medium access control (MAC) mechanism, and they require vehicles to exchange periodic awareness messages to avoid dangerous situations. When the density of vehicles increases, the MAC layer will suffer from radio channel congestion problems, and this may affect the various VANET applications, especially safety applications. Therefore, the decentralized congestion control (DCC) mechanism has been specified by ETSI to mitigate the channel congestion; this was achieved by adapting the transmission parameters, such as the transmit power and data-rate. However, many research studies have demonstrated limitations and a low performance of DCC, especially when the channel load is extremely high. To deal with this, in this paper, we investigate a new promising technique, called the transmission timing control (TTC), to control the channel load for periodic cooperative awareness. It consists of spreading the transmissions over time in order to avoid contention on the transmission channel. The objective of the paper is to propose an analytical study to calculate the probability of successful transmission using TTC. The demonstrated results show the efficiency of our timing control-enabled scheme to deal with the channel load on top of different conditions.

SEEK Mobility Adaptive Protocol Destination Seeker Media Access Control Protocol for Mobile WSNs

The mobile wireless sensor network (WSN) is an emerging field as it widens the scope of applications where sensor networks can be applied. Generally, mobility in wireless communications degrades how well each pair of nodes communicate with one another. In WSN, the effect is higher because nodes have limited communication and computational capabilities. Those limitations create a challenging environment for the operation of sensor node communications. This paper proposes an energy-efficient media access control (MAC) protocol with mobility adaptive throughput based on a carrier-sense multiple access with collision avoidance MAC mechanism called the SEEK-mobility adaptive protocol (SEEK-MADP). SEEK-MADP uses a unique control packet operation to transfer data packets through as many nodes as possible in one duty cycle. The control packets, SYNC and RTS, are merged into one packet (SEEK). SEEK is then transferred to the downstream nodes to establish a connection between a stream of nodes in a duty cycle. This process minimizes the energy consumed by the handshaking process between the connected nodes. To increase throughput, the data period is adaptive to minimize/maximize the data packets according to the movement speed of the sender/receiver nodes. The proposed algorithm is assessed via extensive simulations in mobile scenarios using Network Simulator version 2. The final results show that the SEEK-MADP outperforms MAC protocols, sensor MAC (S-MAC), and SMAC with adaptive listening, which have shown good performance in mobile scenarios. The performance of the proposed algorithm is better than that of IEEE 802.15.4 standard MAC mechanism at mobile scenarios.

Enhancing LoRaWAN scalability with Longest First Slotted CSMA

Compelling features such as low power consumption and low complexity make LoRaWAN one of the most promising technologies to provide long-range connectivity to resource-constrained devices. However, LoRaWAN suffers from limited scalability since it uses an Aloha-based protocol for accessing the channel that causes a huge amount of frame collisions when the number of devices (or the network load) is high. This paper presents LFS-CSMA, a new medium access control mechanism that enhances the scalability of LoRaWAN networks by just combining the well-known slotted Aloha and CSMA schemes in a novel manner. With LFS-CSMA, longer frames are transmitted earlier within a given timeslot. Thus, devices with short frames to be transmitted can check the channel availability before sending them and avoid collisions if they detect an ongoing transmission. Performance results show that LFS-CSMA causes far less collisions than traditional MAC mechanisms, thus improving the scalability of LoRaWAN networks significantly.

A Preamble-Based MAC Mechanism in Ad-Hoc Network

In this paper, we propose a preamble-based medium access control (P-MAC) mechanism in Ad-Hoc network. Different from traditional carrier sense multiple access (CSMA) in Ad-Hoc network, P-MAC uses a much shorter preamble to establish the network. First, we propose the P-MAC mechanism to shorten the time of establishing the Ad-Hoc network. Based on the P-MAC, we propose a more efficient way to maintain the network. Next, focusing on the power line communication (PLC) network which is a kind of Ad-Hoc network, we propose a frequency division power line communication (FD-PLC) network architecture to obtain the best communication frequency. To obtain the best frequency, i.e., highest signal-to-noise ratio (SNR), we design the frequency sweeping mechanism which can determine the frequency of uplink and downlink communication before the transmitter and receiver communicate. Due to the large-scale networks in industry, P-MAC can be exploited to speed up the establishment of the Ad-Hoc PLC network. Finally, we compare our mechanism with CSMA. Numerical results indicate that our strategy greatly shortens the time of establishing the Ad-Hoc network.

Design and Field Test of a Low-cost Device for Real-time Livestock Tracking Using GPS/LoRa Communication

Highlights Monitoring movement is crucial to improve livestock management. GPS livestock tracking method using LoRa with an effective medium access control mechanism. Adaptive data collection with near real-time monitoring. GPS data were collected for improving home-range management. Low implementation costs with increasing lifespan of the devices. Abstract. Extensive livestock grazing systems are in line with agroecological principles. However, these systems are particularly complex to manage. Developing accurate and reliable monitoring of livestock movements and activities is a promising tool to improve the global performances of these systems. Various livestock management systems have been developed over the past decades, culminating in sophisticated systems in intensive controlled environments that allow the real-time monitoring of movements, behaviors, health and production parameters for livestock individuals/herds (e.g. dairy cattle). However, extensive and semi-extensive systems for which the animals are ranging freely outdoors at least part of the time, are presenting specific challenges for combined tracking data acquisition and communication. In this article, we present a GPS livestock tracking method using LoRa communication with a new medium access control mechanism. The node lifespan and performance of the system were evaluated in real on-farm conditions in three different locations in Thailand and Vietnam. The results showed that our system performed adequately well in terms of position accuracy and timeliness. The accuracy of GPS data collected are compatible with their usage for improved rangeland management, monitoring livestock movements and impacts on the environment, and for back-tracking epidemiological movements and contacts of individuals/herds to control diseases outbreaks. The communication system via LoRa allowed to some extent real-time location of livestock herds by farmers due to instant position updates to the Internet, although the performance depended largely on the relief of the landscape surrounding the rangeland used. Finally, reducing costs and increasing the lifespan of the devices remain critical objectives to foster the adoption of such system by farmers and by certification groups to provide field-based evidence for the traceability and quality control of livestock and animal products raised under healthy and environmental-friendly productions systems. Our current design, if produced in a large quantity of at least 100 units, would cost approximately $65 USD per unit, with an average lifetime of 20 days. Keywords: Cattle, GPS, LoRa, Tracking system.

Elastic hybrid MAC protocol for wireless sensor networks

The future is moving towards offering multiples services based on the same technology. Then, billions of sensors will be needed to satisfy the diversity of these services. Such considerable amount of connected devices must insure efficient data transmission for diverse applications. Wireless sensor network (WSN) represents the most preferred technology for the majority of applications. Researches in medium access control (MAC) mechanism have been of significant impact to the application growth because the MAC layer plays a major role in resource allocation in WSNs. We propose to enhance a MAC protocol of WSN to overcome traffic changes constraints. To achieve focused goal, we use elastic hybrid MAC scheme. The main interest of the developed MAC protocol is to design a medium access scheme that respect different quality of services (QoS) parameters needed by various established traffic. Simulation results show good improvement in measured parameters compared to typical protocol.

Adaptive dynamic duty cycle mechanism for energy efficient medium access control in wireless multimedia sensor networks

AbstractMultimedia applications require significantly higher bandwidth than conventional textual applications. Furthermore, multimedia stream requires time sensitive and involves high‐energy consumption, which become more challenging on resource constrained networks such as wireless multimedia sensor network (WMSN). As a result, developing an energy efficient algorithm to prolong the network lifetime is the main reoccurring issue in WMSN. Although the duty cycling mechanism has been proven to be an efficient solution for energy saving in various WSN applications, the tradeoff between energy efficiency and quality of service (QoS) on WMSN remains striking. In this article, an adaptive dynamic duty cycle mechanism for energy‐efficient medium access control (ADE‐MAC) is proposed for WMSNs. ADE‐MAC uses a unique asynchronous duty cycle approach to schedule the sleep pattern of each sensor node which can be adapted according to the incoming traffic rate and queuing delay at each node. In the proposed system, the overhead of synchronization is avoided because every node has its own scheduling sleep, and the only sender node must wake up the receiver nodes by using preambles packets. The findings that result from comprehensive simulation show that ADE‐MAC outperforms the baseline approaches in term of delivery ratio by 12%, less packet overhead by 28%, less end‐to‐end delay by 19%, and less power consumption by 41% compared to the baseline mechanisms.

Architecting a priority-based dynamic media access control mechanism in Wireless Network-on-Chip

Wireless Network-on-Chip (WiNoC) are being examined for parallel applications to improve the performances by reducing multi-hop latency. Wireless nodes handle massive data transmission assignment, the data bandwidth and energy efficiency of the WiNoC architecture can be improved by establishing wireless links to respond to dynamically changing traffic patterns. Among them, the wireless token mechanism is widely used, since it would take little additional hardware overhead and simple operation process. However, the traditional wireless token mechanism is a time-division-multiplexed fair strategy, and cannot well cope with non-uniform traffic patterns. In this paper, a priority-based dynamic media access control (MAC) mechanism in wireless network-on-chip is architected by redefining MAC mechanism, which aims to make wireless MAC protocols more suitable for non-uniform traffic patterns. Experimental results show that the proposed scheme in this paper guarantees the network performance equivalent to the traditional token mechanism in random traffic mode, and the network throughput is increased by 14%–15% in the hotspot mode. Compared with the traditional token mechanism, the average packet delay is greatly reduced before the saturation point with little extra hardware overhead introduced simultaneously.

Thorough Performance Evaluation & Analysis of the 6TiSCH Minimal Scheduling Function (MSF)

IEEE Std 802.15.4-2015 Time Slotted Channel Hopping (TSCH) is the de facto Medium Access Control (MAC) mechanism for industrial applications. It renders communications more resilient to interference by spreading them over the time (time-slotted) and the frequency (channel-hopping) domains. The 6TiSCH architecture bases itself on this new MAC layer to enable high reliability communication in Wireless Sensor Networks (WSNs). In particular, it manages the construction of a distributed communication schedule that continuously adapts to changes in the network. In this paper, we first provide a thorough description of the 6TiSCH architecture, the 6TiSCH Operation Sublayer (6top), and the Minimal Scheduling Function (MSF). We then study its behavior and reactivity from low to high traffic rates by employing the Python-based 6TiSCH simulator. Our performance evaluation results demonstrate that the convergence pattern of MSF is the root cause of the majority of packet losses observed in the network. We also show that MSF is prone to over-provisioning of the network resources, especially in the case of varying traffic load. We propose a mathematical model to predict the convergence pattern of MSF. Finally we investigate the impact of varying parameters on the behavior of the scheduling function.

An adaptive backoff and dynamic clear channel assessment mechanisms in IEEE 802.15.4 MAC for wireless body area networks

The low power connectivity and short distance communication qualities of the IEEE 802.15.4 standard suits its application in wireless body (personal) area networks (WBAN). IEEE 802.15.4 protocol use carrier sense multiple access and collision avoidance (CSMA-CA) medium access control (MAC) mechanism for aperiodic data communication; however, it faces performance degradation with a gradual increase in the number of network devices. Performance challenges arise due to; several heterogeneous and dynamic packet sources sharing limited resources during contention in a finite backoff period, association delay, and traffic channel access through clear channel assessment (CCA) algorithms. Due to such constraints, channel conditions increase packet collision and queuing delay, which raises power demand and impedes performance indicators, such as throughput, packet delivery ratio (PDR), and end to end (E2E) delay. This article proposes an alternative combination of the backoff and CCA adaptation mechanisms to improve WBAN performance characteristics in a highly dynamic environment considering network residue energy, PDR, throughput, and E2E delay. We use the Markov model to demonstrate a theoretical analysis of the proposed CSMA-CA MAC mechanism. A comparative study shows the proposed methods outperform conventional protocol in PDR, throughput, and reduced E2E delay by 13.1%, 21.44%, and 41.13%, respectively, where energy efficiency drops by 0.43%.

A new medium access control mechanism for energy optimization in WSN: traffic control and data priority scheme

Over the last few years, energy optimization in wireless sensor networks (WSNs) has drawn the attention of both the research community and actual users. Sensor nodes are powered by attached batteries that are considered as a critical aspect of sensor nodes design. Besides, the constraint of the limited battery capacity is associated with the concern on how to reduce the energy consumption of nodes to extend the network lifetime. In this context, the purpose of this study is to implement an adaptive medium access control (MAC) for energy saving and traffic control enhancement. This program was designed to arrange nodes into two priority groups according to their traffic rate and data transmission packet delay. This fuzzy algorithm depends on their queue length where it is implemented into the carrier sense multiple access with collision avoidance (CSMA/CA) algorithm. However, other types of nodes should send their data during the contention-free period with a GTS reallocation scheme. Those nodes are classified as low priority access to the medium, and their data transmission is scheduled using time division multiple access methods. Moreover, this proposed scheme dynamically adjusts the contention access period length to ensure that nodes can complete their data transmission during the same super-frame. Simulation results are done using the network simulator tool (NS-2), and it has improved efficiency regarding the IEEE-802.15.4 standard.

A simple cross-layer mechanism for congestion control and performance enhancement in a localized multiple wireless body area networks

Commercialization of the wireless body area network (WBAN) envisions future new normal for WBAN devices coexistence in a localized area. The coexistence may allow devices to freely change positions, associate, or dissociate with the neighbours as users interact. Devices’ interaction in a stationary or mobile fashion radiates heat and also competes for the limited network resources resulting to unreliable communication and other performance challenges. Besides alarming user safety, device mobility affects network performance through topology changes, which result to recursive link disconnections, energy waste, packet delay, degraded throughput, and congestion due to excessive control messaging during route repair. In this article, we propose WBAN performance optimization criteria focusing on improving energy efficiency, network throughput, and reducing the end to end delay in multiple existence schemes. Firstly, we propose an alternative routing algorithm, whose routing decision depends on a cost function considering the parameterized residue energy to node distance ratio, link energy reliability, and specific heat absorption in addition to node sequence number and hop count as fundamental route selection metrics. Secondly, we implement congestion control adaptation in the medium access control (IEEE 802.11MAC) mechanism, which improves throughput, reduces congestion, and delay. Due to link discontinuities during mobility, we demonstrate a comparative network performance to address the effect of WBAN speed at different hello intervals. The comparative analysis show, protocol implementation with a cross-layer approach outperforms the conventional protocol without MAC adaptations in terms of energy efficiency, network throughput, and a reduced end to end delay, by an average of 0.45%, 2.8%, and 13.7%, respectively.

A dynamic resource assignment scheme with aggregation node selection and power conservation for WBAN based applications

For real-time health status monitoring and treatment, the development of an efficient resource management scheme is an important research issue for wireless body area network (WBAN) based medical applications. To cope with the different application requirements, the coordination of cluster head selection, dynamic medium access control mechanism (MAC) considering both critical and normal data transfer, end-to-end connectivity, data transfer to multiple processing and destination device, intermediate node selection, and proper path selection, is mandatory. In this paper, a dynamic resource assignment scheme is proposed that assigns bandwidth and medical server resources to WBAN users for data transfer without any backoff delay and selects both the cluster head node and aggregation sensor node for the aid of WBAN sensors. The evaluation results show that the proposed dynamic resource assignment scheme performs better results than the compared random assignment scheme in terms of the delay overhead, energy overhead, goodput, and network lifetime.

Self‐Organized Efficient Spectrum Management through Parallel Sensing in Cognitive Radio Network

In this paper, we propose an innovative self‐organizing medium access control mechanism for a distributed cognitive radio network (CRN) in which utilization is maximized by minimizing the collisions and missed opportunities. This is achieved by organizing the users of the CRN in a queue through a timer and user ID and providing channel access in an orderly fashion. To efficiently organize the users in a distributed, ad hoc network with less overhead, we reduce the sensing period through parallel sensing wherein the users are divided into different groups and each group is assigned a different portion of the primary spectrum band. This consequently augments the number of discovered spectrum holes which then are maximally utilized through the self‐organizing access scheme. The combination of two schemes augments the effective utilization of primary holes to above 95%, even in impasse situations due to heavy primary network loading, thereby achieving higher network throughput than that achieved when each of the two approaches are used in isolation. By efficiently combining parallel sensing with the self‐organizing MAC (PSO‐MAC), a synergy has been achieved that affords the gains which are more than the sum of the gains achieved through each one of these techniques individually. In an experimental scenario with 50% primary load, the network throughput achieved with combined parallel sensing and self‐organizing MAC is 50% higher compared to that of parallel sensing and 37% better than that of self‐organizing MAC. These results clearly demonstrate the efficacy of the combined approach in achieving optimum performance in a CRN.

Performance Analysis of Synchronous Multi-Radio Multi-Link MAC Protocols in IEEE 802.11be Extremely High Throughput WLANs

The representative media access control (MAC) mechanism of IEEE 802.11 is a distributed coordination function (DCF), which operates based on carrier-sense multiple access with collision avoidance (CSMA/CA) with binary exponential backoff. The next amendment of IEEE 802.11 being developed for future Wi-Fi by the task group-be is called IEEE 802.11be, where the multi-link operation is mainly discussed when it comes to MAC layer operation. The multi-link operation discussed in IEEE 802.11be allows multi-link devices to establish multiple links and operate them simultaneously. Since the medium access on a link may affect the other links, and the conventional MAC mechanism has just taken account of a single link, the DCF should be used after careful consideration for multi-link operation. In this paper, we summarize the DCFs being reviewed to support the multi-radio multi-link operation in IEEE 802.11be and analyze their performance using the Markov chain model. Throughout the extensive performance evaluation, we summarize each MAC protocol’s pros and cons and discuss essential findings of the candidate MAC protocols.

A Network-Aware Internet-Wide Scan for Security Maximization of IPv6-Enabled WLAN IoT Devices

Despite unprecedented advancements, wireless local area network (WLAN) technologies for the Internet of Things (IoT), such as IEEE 802.11ah (i.e., WiFi-HaLow), are prone to serious security threats, owing to their constrained computational and memory resources, which limit the use of heavyweight intrusion protection and security protocols. To address this problem, security administrators (sec-admins) must perform regular and comprehensive vulnerability assessments of IoT devices. An Internet-wide port scan (IWPS) is the initial step. However, the medium access control mechanism of IEEE 802.11ah, designed specifically for heterogeneous IoT traffic and low-power operations, can degrade network performance in the case of traditional port-scan traffic. Moreover, Internet-security (IPSec) protocol support is mandatory for IPv6-enabled IoT devices to ensure data confidentiality, integrity, and availability. Although the objective of a port scan is to improve IoT security, the resultant network performance can adversely affect IPSec services. Therefore, in this study, we optimize the IWPS to maximize the IoT security over IEEE 802.11ah WLAN. To this end, we propose novel mathematical models to evaluate IoT security based on port-scan network performance and IPsec services, which derives an optimal scan rate for sec-admins. The effectiveness of the proposed framework is verified by comprehensive numerical analysis, which shows that our approach minimizes the risk to IoT devices while probing them at an optimal scan rate.