Carrier Sense Multiple Access With Collision Avoidance Research Articles

Research on AUV Multi-Node Networking Communication Based on Underwater Electric Field CSMA/CA Channel

To address the issues of high attenuation, weak reception signal, and channel blockage in the current electric field communication of underwater robots, research on autonomous underwater vehicle (AUV) multi-node networking communication based on underwater electric field Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) channel was conducted. This article, first through simulation, finds that the Optimized Link State Routing (OLSR) protocol has a smaller routing packet delay time and higher reliability compared to the Ad Hoc On-Demand Distance Vector (AODV) protocol on underwater electric field CSMA/CA channels. Then, a 2FSK underwater electric field communication system was established, and dynamic communication experiments were carried out between two AUV nodes. The experimental results showed that within a range of 0 to 3.5 m, this system can achieve underwater dynamic electric field communication with a bit error rate of 0 to 0.628%. Finally, to avoid channel blockage during underwater AUV multi-node communication, this article proposes a dynamic backoff method for AUV multi-node communication based on CSMA/CA. This system can achieve dynamic multi-node communication of underwater electric fields with an error rate ranging from 0 to 0.96%. The research results have engineering application prospects for underwater cluster operations.

Hybrid vehicular access protocol and message prioritization for real-time safety messaging

Real-time safety services rely on the exchange of messages to enhance the operations of connected and automated vehicles (CAVs). These safety messages convey vital information about traffic conditions, enabling drivers to take necessary measures to prevent accidents. The timely and reliable delivery of these messages is essential, necessitating efficient channel access. Vehicular Deterministic Access (VDA) is employed as a channel access scheme with distinct priorities and stringent timing guidelines, particularly for urgent safety warnings. In this paper, we propose a hybrid approach that combines VDA and Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) protocols, along with a message prioritization algorithm, to ensure efficient and reliable communication of safety messages in vehicular networks. Our approach leverages the strengths of both VDA and CSMA/CA to avoid message collisions; VDA is more efficient under high traffic loads, while CSMA/CA is better suited for low traffic loads. Additionally, the incorporation of the message prioritization algorithm ensures strict deadline guarantees for high-priority messages, such as Decentralized Environmental Notification Messages (DENMs). We evaluate our proposed solution using the Artery simulation framework. Our results show over a 93% delivery rate for DENM exchanges while maintaining low collision probability across various traffic loads. This research provides practical guidance for the development of efficient and reliable communication systems for CAVs. It also offers a detailed analysis of the trade-offs among different access protocols and message prioritization strategies in vehicular networks.

Mathematical analysis of busy tone in full-duplex optical MAC for hidden node mitigation

This article provides the mathematical analysis of carrier sense multiple access with collision avoidance (CSMA/CA) media access control (MAC) protocol of IEEE 802.15.7 optical wireless communication (OWC). While the prior works have performed the OWC CSMA/CA mathematical analysis using the Markov models, deviation from the simulation results has been observed. We address this by improving the Markov model calculations, which display a mere 0.2% throughput deviation, nearly matching the simulation results. Furthermore, we work on the hidden node problem of the OWC networks. This problem is solved in literature by using various full-duplex communication methods, such as bi-directional data transmission and the busy tone signal; the latter is employed in our previous work on full-duplex optical MAC (FD-OMAC). These techniques increase the coverage area of the nodes by utilizing an access point (AP) as a relay node. However, the AP response is delayed by the processing time, causing an unexpected network behavior. The quantitative effect of this delay remains unexplored, which is critical for optimizing the OWC network. We bridge this gap by extending the proposed Markov analysis to model CSMA/CA and the aforementioned full-duplex techniques. This work equips readers with mathematical insights for future OWC MAC layer enhancements.

Multi-Disjoint Path opportunistic networks with Hidden Markov Chain modeling

Advancing the efficiency and reliability of wireless sensor networks is a paramount pursuit in modern networking research. In this context, we introduce a groundbreaking approach based on Hidden Markov Chain (HMC) modeling with opportunistic routing, harnessed by the Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) mechanism. Our innovative algorithm addresses key challenges in Wireless Body Area Networks, including delay, throughput, and bandwidth utilization. By strategically integrating the HMC model, which captures intricate state transitions and emission probabilities, our proposed method introduces a robust solution for optimizing node connections and routing decisions. This fusion of HMC and opportunistic routing capitalizes on the strengths of both paradigms, enhancing the network's ability to make intelligent decisions in dynamic scenarios. Through rigorous simulations, we showcase the algorithm's prowess in achieving efficient data transmission. The empirical evidence from these simulations underscores the algorithm's superiority when juxtaposed against state-of-the-art mechanisms such as Simple Multi-Packet Access (SMPA) and Priority-based Congestion-avoidance Routing Protocol (PCRP). Our algorithm not only outperforms existing solutions in terms of delay, throughput, and bandwidth utilization, but it also showcases its ability to adapt to varying network conditions, making it a versatile tool for diverse applications.

Learning-Based Autonomous Channel Access in the Presence of Hidden Terminals

We consider the problem of autonomous channel access (AutoCA), where a group of terminals tries to discover a communication strategy with an access point (AP) via a common wireless channel in a distributed fashion. Due to the irregular topology and the limited communication range of terminals, a practical challenge for AutoCA is the hidden terminal problem, which is notorious in wireless networks for deteriorating throughput and delay performances. To meet the challenge, this paper presents a new multi-agent deep reinforcement learning paradigm, dubbed MADRL-HT, tailored for AutoCA in the presence of hidden terminals. MADRL-HT exploits topological insights and transforms the observation space of each terminal into a scalable form independent of the number of terminals. To compensate for the partial observability, we put forth a look-back mechanism such that the terminals can infer behaviors of their hidden terminals from the carrier-sensed channel states as well as feedback from the AP. A window-based global reward function is proposed, whereby the terminals are instructed to maximize the system throughput while balancing the terminals' transmission opportunities over the course of learning. Considering short-packet machine-type communications, extensive numerical experiments verified the superior performance of our solution benchmarked against the legacy carrier-sense multiple access with collision avoidance (CSMA/CA) protocol.

A Torpor-based Enhanced Security Model for CSMA/CA Protocol in Wireless Networks

Mobile wireless networks enable the connection of devices to a network with minimal or no infrastructure. This comes with the advantages of ease and cost-effectiveness, thus largely popularizing the network. Notwithstanding these merits, the open physical media, infrastructural-less attributes, and pervasive deployment of wireless networks make the channel of communication (media access) vulnerable to attacks such as traffic analysis, monitoring, and jamming. This study designed a virtual local area network (VLAN) model to circumvent virtual jamming attacks and other intrusions at the Media Access Control (MAC) layer of the Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) protocol. A Torpor VLAN (TVLAN) Data Frame Encapsulation and the algorithm for T-VLAN security in CSMA/CA were formulated and presented. A simulation experiment was conducted on the model using OMNeT++ software. The performance metrics used to evaluate the model were packet delivery ratio, network throughput, end-to-end channel delay, and channel load. The simulation results show that the TVLAN defence mechanism did not increase the channel load arbitrarily during TVLAN defence. similarly, the system throughput was shown to be 82% during TVLAN defence. Nevertheless, the network delay of the system during TVLAN defence was significantly high but the channel load was 297 when the TVLAN security mechanism was launched. These results demonstrate the model’s ability to provide a survivability mechanism for critical systems when under attack and add a security layer to the CSMA/CA protocol in wireless networks. Such a remarkable performance is required of a CSMA/CA infrastructure for improving the cybersecurity posture of a wireless network.

Effects Investigation of MAC and PHY Layer Parameters on the Performance of IEEE 802.15.6 CSMA/CA

The recently released IEEE 802.15.6 standard specifies several physical (PHY) layer and medium access control (MAC) layer protocols for variety of medical and non-medical applications of Wireless Body Area Networks (WBAN). The most suitable way for enhancing network performance is to be the choice of different MAC and PHY parameters based on quality of service (QoS) requirements of different applications. The impact of different MAC and PHY parameters on the network performance and the tradeoff relationship between the parameters are essential to overcome the limitations of exiting carrier sense multiple access with collision avoidance (CSMA/CA) scheme of IEEE 802.15.6 standard. To address this issue, we develop a Markov chain-based analytical model of IEEE 802.15.6 CSMA/CA for all user priorities (UPs) and apply this general model to different network scenarios to investigate the effects of the packet arrival rate, channel condition, payload size, access phase length, access mechanism and number of nodes on the performance parameters viz. reliability, normalized throughput, energy consumption and average access delay. Moreover, we conclude the effectiveness of different access phases, access mechanisms and user priorities of intra-WBAN.

Dynamic adaptation of contention window boundaries using deep Q networks in UAV swarms

In flying ad hoc networks (FANET), medium access layer (MAC) protocols play an essential role in ensuring better network performance. The effective utilization of network resources and providing access fairness are key research issues in this area, and the contention window size directly influences these factors. This paper mainly focuses on addressing the upper and lower boundaries of the contention window in Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA) with a binary exponential back-off algorithm. Existing solutions include static and dynamic window adjustment techniques only to update the upper boundary of the contention window size. However, the static window adjustment technique is unsuitable for changing network conditions, while the dynamic window adjustment technique may need to be more efficient in dense network environments. The proposed solution uses a Deep Q-learning algorithm(DQN) framework to adjust the contention window adaptively based on the reward function, resulting in efficient and dynamic adaptation to changing network conditions among unmanned aerial vehicles (UAV). The proposed methodology is evaluated through simulations, and performance is measured using channel utilization, efficiency, delay, and collision rate. The simulation findings show that, in comparison to generic MAC protocols, the proposed algorithm is 5% more efficient in throughput and incurs a four-fold reduction in delay.

Analysis of the Efficiency of Various Receipting Multiple Access Methods with Acknowledgement in IoT Networks

An Internet of things (IoT) network is a distributed set of “smart” sensors, interconnected via a radio channel. The basic method of accessing the radio channels for these networks is Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA), in which access is carried out on the basis of contention, and confirmation of the correct reception of the packet is achieved using a receipt. If the sizes of information packets are small and comparable to the sizes of receipts, then the transmission of receipts requires a significant bandwidth of the channel, which reduces the efficiency of the network. This problem exists not only for IoT networks but also for monitoring systems, operational management of fast processes, telemetry, short messaging and many other applications. Therefore, an urgent task is to develop effective methods of multiple random access in the transmission of short information packets, the size of which is comparable to the size of receipts. To solve this problem, the authors proposed modifications of CSMA/CA random access in which, when packet collisions are detected, a diagnostic message (DM) is generated and transmitted in the broadcast mode. Based on simulation modeling, it is shown that in a wide range of network loads, the proposed random access options provide an increase in network capacity (the number of connected subscribers) of 1.5–2 times compared to the basic CSMA/CA access method when the size of the information packet is an order of magnitude larger than the size of receipts. The variant of access without acknowledgment is also considered, in which, as shown by the simulation results, at sufficiently large loads, the network can go into an unstable state.

Distributed Batteryless Access Control for Data and Energy Integrated Networks: Modeling and Performance Analysis

Radio-frequency (RF) signals are capable of simultaneously transferring data and energy from a hybrid access point (HAP) toward battery-powered and batteryless wireless devices. Battery-powered and batteryless wireless devices with the capability of RF energy harvesting need a distributed access control protocol with collision avoidance to achieve higher energy efficiency. We study the performance of a data and energy integrated network (DEIN) that adopts an enhanced carrier sensing multiple access with collision avoidance (CSMA/CA) protocol. Each device in this network can switch to RF energy harvesting mode or data reception mode according to HAP’s instruction, and freezes its backoff counter when energy storage is insufficient. By invoking a three-dimensional (3D) Markov chain, we model the operating behaviors of batteryless wireless devices and an HAP in a DEIN. Apart from backoff operations of devices, the 3D Markov chain also depicts their dynamic energy changes, including RF energy harvesting and energy consumption. Wireless devices consume energy harvested from the HAP’s downlink transmissions for powering their data upload and random backoff. With the aid of the 3D Markov chain, the upload throughput of devices can be obtained in semi-closed-form. Moreover, a decoupling method is proposed to approximate throughput performance with low complexity. The accuracy of our theoretical model is validated by simulation results. By characterizing the impact of various parameters on throughput performance, a design guideline for a DEIN with a distributed batteryless access protocol is provided.

Use of Logarithmic Rates in Multi-Armed Bandit-Based Transmission Rate Control Embracing Frame Aggregations in Wireless Networks

Herein, we propose the use of the logarithmic values of data transmission rates for multi-armed bandit (MAB) algorithms that adjust the modulation and coding scheme (MCS) levels of data packets in carrier-sensing multiple access/collision avoidance (CSMA/CA) wireless networks. We argue that the utilities of the data transmission rates of the MCS levels may not be proportional to their nominal values and suggest using their logarithmic values instead of directly using their data transmission rates when MAB algorithms compute the expected throughputs of the MCS levels. To demonstrate the effectiveness of the proposal, we introduce two MAB algorithms that adopt the logarithmic rates of the transmission rates. The proposed MAB algorithms also support frame aggregations available in wireless network standards that aim for a high throughput. In addition, the proposed MAB algorithms use a sliding window over time to adapt to rapidly changing wireless channel environments. To evaluate the performance of the proposed MAB algorithms, we used the event-driven network simulator, ns-3. We evaluated their performance using various scenarios of stationary and non-stationary wireless network environments including multiple spatial streams and frame aggregations. The experiment results show that the proposed MAB algorithms outperform the MAB algorithms that do not adopt the logarithmic transmission rates in both the stationary and non-stationary scenarios.

A score based link delay aware routing protocol to improve energy optimization in wireless sensor network

The Wireless Sensor Network (WSN) is the most appearing expertise that has potential applications broad ranges that include environment examining, smart spaces, medical systems, and robotic study. Energy efficiency is a consideration of vital design for WSN. The collision is occurred owing to the transmission of data from the sensor nodes and the traffic at the SINK node is high because of the excess data transmission by the sensor nodes. An essential division of the consumption of resources in a WSN is managed by the mechanism of Medium Access Control (MAC). An existing MAC protocols initiated for the utilization of WSNs single channel for data transmission. The deployment of wireless sensor nodes is concerned in the harsh environment in which the drastic change of conditions suffers from sudden changes in the status of a node and the quality of a link. With limited energy, the sensor nodes are supplied and a major concern is towards improving the lifetime of a network. To deal with these issues, a novel and simple routing mechanism Score based Link Delay Aware Routing (SBLDAR) is proposed, which utilizes the multi-channel MAC procedure comprises of Carrier Sense Multiple Access/ Collision Avoidance (CSMA/CA), to exchange the data, the activity of Time Division Multiple Access (TDMA) sequencing nodes and also Frequency Division Multiple Access FDMA) to allow collision-free exchange simultaneously. Also, in order to overcome this issue, an approach has been put out in this work that involves leveraging a variety of trust variables to identify malicious nodes and then using fuzzy based Modified Sun Flower Optimization (FMSFO) algorithm to elect an effective cluster head. The score based route selection increases the network lifetime and improves network performance. By comparing with the other protocols, the proposed SBLDAR combined with the technique of multi-MAC protocol has shown that it increases the network’s overall performance based on the simulation studies.

Timeliness of wireless sensor networks with random multiple access

In this paper, we consider a wireless sensor network in which N sensor nodes deliver the observed information of interest to a remote receiver by competing for a sharing channel through the Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) protocol or the slotted ALOHA protocol. For this network, we evaluate the information freshness of the two random multiple access protocols using the age of information (AoI) metric. In order to explicitly express the average AoI of the CSMA/CA based network, we establish an equivalent and tractable transmission model for the network, in which the transmission probabilities and the collision probabilities are assumed to be identical over time and among sensor nodes. For the slotted ALOHA based network, we derive the average AoI by focusing on a randomly chosen reference node. Our theoretical results show that 1) the transmission probability and collision probability of the two networks increase with both the arrival rate and the number of sensor nodes; 2) with the same transmission probability, the average AoI of the CSMA/CA based network is always smaller than that of the slotted ALOHA based network, no matter how the arrival rate and the number of nodes change. Our Monte Carlo simulation results also validate the correctness of our theoretical calculations.

CSMA Protocol performance with dynamic spreading factor in LPWAN networks with LoRa RF transceivers

Long Range (LoRa) is a spread spectrum modulation technology designed for Low-Power Wide-Area Networking (LPWAN) with a growing application in Internet of Things (IoT), which plays an important role in the global digitalization process. The expansion of LORAWAN networks demands careful circuit, system and network design to improve energy efficiency and quality of service. To support this task, advanced CAD tools can offer reliable network simulations results, where the effects of building blocks can be found. LoRaSim, one of the most popular simulators available for LoRa and LoraWan, had solely implemented an ALOHA access model protocol, which is not the most common protocol in real life scenarios. To mitigate this limitation and taking advantage of the open-source nature of both LoRaWAN and LoRaSim, it is proposed a Carrier Sense Multiple Access/ Collision Avoidance (CSMA/CA) protocol extension, as well as active adaptive parameters selection to cope with collisions. To demonstrate the effectiveness of these additions to the base solution, a comparison between both on different scenarios and their simulated performance key indicators will be presented.

Graph-based conflict-free MAC protocol and conflict analysis for a two-layer ultraviolet communication network

To efficiently exploit the space division multiplexing of ultraviolet (UV) communication, we apply link coverage characteristics to construct a conflict graph and design conflict-free protocols for a two-layer UV communication network. The network is divided into two layers: the first-layer network forms a backbone and the second-layer network serves as local access. We construct a routing model and medium-access control (MAC) model. Then we propose Routing-MAC joint scheduling for the first-layer network based on the conflict graph. We investigate the system throughput and delay of joint scheduling under different node intensities. For second-layer networks, we propose a multi-link conflict-free protocol adopting protocol frames of carrier sense multiple access with collision avoidance (CSMA/CA). Numerical results show that the multi-link conflict-free protocol can improve the system throughput by more than 100% compared with CSMA/CA. Moreover, we perform a conflict analysis on the proposed protocols to investigate the influence of conflict intensity. According to the conflict analysis, we optimize the path planning of Routing-MAC joint scheduling to reduce the average delay of the network. Numerical results show that the optimized Routing-MAC joint scheduling leads to larger system throughput and lower delay.

Sensors Scheduling for Remote State Estimation Over an Unslotted CSMA/CA Channel

This article investigates the sensor selection problem for remote state estimation. A set of sensors measures a process's state and sends the measurements to a remote estimator over an unslotted carrier sense multiple access/collision avoidance (CSMA/CA) channel in IEEE 802.15.4-based wireless body area networks. This article aims to answer which sensors should be selected according to probability so that the state estimation error covariance and the energy consumption of sensors can be optimized. A common assumption in most existing methods about sensor scheduling is that the packet loss process is unrelated to the channel input. This article analyzes the relationship between channel input and packet loss rate by modeling the communication process. A scheduling scheme is proposed to increase channel utilization from the perspective of sensor information fusion. Then the constraint on the performance metrics is presented. By transforming the sensor selection problem into a constrained optimization problem, the solution to the optimization problem is obtained by a numerical algorithm. Finally, the validity of the model and the feasibility of the sensor scheduling are demonstrated by a numerical simulation.

A novel ultraviolet communication channel access protocol based on competition mechanism

Media Access Control (MAC) protocol in the Ultraviolet (UV) communication plays an important role in mobile Ad-hoc networks. However, the throughput of the existing UV MAC competitive protocol will decline with a large number of nodes. In this paper, a novel UVCA channel access protocol (UV Conflict Avoidance protocol) is proposed based on the principle of ultraviolet power superposition. The UVCA protocol can reduce the conflict loss of multi-node competing access by a special control frame. Using MATLAB, throughput and delay performance of the UVCA protocol are simulated and analyzed under the difference of nodes number, transmission probability and frame length. Compared with Carrier Sense Multiple access with Collision Avoidance (CSMA/CA) protocol, the UVCA protocol has some features of simple implementation, low protocol complexity, higher channel utilization and strong anti-collision ability. When the number of nodes change from 2 to 20, the maximum throughput of UVCA protocol is 1.02–1.27 times than that of CSMA/CA, it indicates the new UVCA protocol can meet to the requirements of the multi-node UV-ad hoc network communication.

Starvation mitigation and priority aware of CSMA/CA in WSN with implementing Markov chain model

In the domain of wireless networking, the Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) has a wide range of applications. Based on CSMA/CA, the IEEE 802.15.6 MAC protocol is used for the body network area. For reduction of the collision’s probability, the accessing the medium, the CSMA/CA uses a distributed coordination function. For a node to transmit the data in CSMA/CA, the channel is sensed and then the transmission is initiated if it happens to be idle. For a contention period, the node is deferred for transmission, if the channel happens to be busy. When the multiple nodes attempt to access a channel, their issue of contention will be solved by this mechanism. As a side effect, there is starvation of the decaying nodes, and the data latency is noticeably increased. For a delay-sensitive application, CSMA/CA protocol becomes inapplicable as the higher risk of fatality is associated with the delay critical applications, such as vehicle cohesion avoidance system and the health-care system.In the modeling process, the channel load is not taken into account at first. For high-priority services, channel detection is performed once. For low priority services, channel detection is performed twice. Markov chain model is used to analyze the influence of algorithm parameter setting on network performance, and it shows great efficiency. Accidents may become inevitable with the exponential latency in the receiving of an emergency notification. Hence, for backing up the loopholes of IEEE 802.15.6 MAC protocol and uprising the response rate of the emergency and warning cases, the author substitutes back off the procedure by proposing a solution that considers the level of emergency or the priority of the message with the help of associated contention window and level of emergency. This reduces the chances of starvation as well. The techniques for CSMA/CA that are priority aware, surely outperform the state of the art back off and this is proved by simulation that the model has enhanced the efficiency of the channel in regards to throughput, delays in transmission, utilization of the bandwidth.

A CSMA/CA based MAC protocol for hybrid Power-line/Visible-light communication networks: Design and analysis

Hybrid Power-line/Visible-light Communication (HPVC) network has been one of the most promising Cooperative Communication (CC) technologies for constructing Smart Home due to its superior communication reliability and hardware efficiency. Current research on HPVC networks focuses on the performance analysis and optimization of the Physical (PHY) layer, where the Power Line Communication (PLC) component only serves as the backbone to provide power to light Emitting Diode (LED) devices. So designing a Media Access Control（MAC) protocol remains a great challenge because it allows both PLC and Visible Light Communication (VLC) components to operate data transmission, i.e., to achieve a true HPVC network CC. To solve this problem, we propose a new HPC network MAC protocol (HPVC MAC) based on Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA) by combining IEEE 802.15.7 and IEEE 1901 standards. Firstly, we add an Additional Assistance (AA) layer to provide the channel selection strategies for sensor stations, so that they can complete data transmission on the selected channel via the specified CSMA/CA mechanism, respectively. Based on this, we give a detailed working principle of the HPVC MAC, followed by the construction of a joint analytical model for mathematical-mathematical validation of the HPVC MAC. In the modeling process, the impacts of PHY layer settings (including channel fading types and additive noise feature), CSMA/CA mechanisms of 802.15.7 and 1901, and practical configurations (such as traffic rate, transit buffer size) are comprehensively taken into consideration. Moreover, we prove the proposed analytical model has the solvability. Finally, through extensive simulations, we characterize the HPVC MAC performance under different system parameters and verify the correctness of the corresponding analytical model with an average error rate of 4.62% between the simulation and analytical results.

A Grouping Algorithm for Random Access Networks and Supermartingale Evaluation

Wireless communications play a critical role in the applications of Internet of Things (IoT). The Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA) is a well-proven wireless random access protocol. A crucial factor affecting the performance of random access networks is “hidden node collision,” which incurs performance degradation and lower resource utilization. Grouping is an efficient strategy for hidden node avoidance. In current IoT networks, the terminals usually have different traffic load, so load balance should be considered when grouping algorithm is designed. To mitigate hidden nodes and achieve load balance simultaneously, we propose a grouping algorithm based on the game theory. By introducing the supermartingale theory, the delay performance of the completed groups is analyzed. Simulations prove that the proposed algorithm alleviates collision, balances traffic, and promotes the efficient guarantee for Quality of Service (QoS).