Medium Access Control Algorithm Research Articles

A Distributed Medium Access Control Algorithm With an Enhanced Physical-Link Layer Interface

A Distributed Medium Access Control Algorithm With an Enhanced Physical-Link Layer Interface

Restrained medium access control on adversarial shared channels

We study the fundamental problem of utilization of the channel shared by stations competing to transmit packets on the channel. In their turn, packets are continuously injected into stations' queues by an adversary at a rate at most ρ packets per round. The aim of the distributed medium access control algorithms is to successfully transmit packets and maintain system stability (bounded queues). We further restrain algorithms by introducing an upper bound k on the allowed number of active stations in any given round. We construct adaptive and full sensing protocols with optimal throughput 1 and almost optimal throughput 1−ϵ (for any positive ϵ), respectively, in a constant-restrained channel. On the opposite side, we show that restricted protocols based on schedules known in advance suffer from a substantial drop of throughput, at most min⁡{kn,1log⁡n}. We compare our algorithms experimentally with well-known backoff protocols.

Analytical Study of Different Parameters of Antenna for Wireless Networks

In this paper, we studied about Wireless networks which is a relatively new and promising key technology for next generation wireless networking that have recently attracted both the academic and industrial interest. Their popularity comes from the fact that they are self-organized, self-configurable and easily adaptable to different traffic requirements and network changes. The high-capacity needs of the access nodes which have to forward the accumulated traffic of their underling users. They have to cope with the delay and other strict quality-of-service (QoS) requirements of the end user applications. They must provide a large enough effective communication range to ensure that no APs (or groups of APs) are isolated from the Internet gateways. In order to satisfy the above requirements, a range of novel techniques has to be exploited. Such technology enablers include but not limited to multi-hopping, various multiple antennas techniques and novel medium access control (MAC) and routing algorithms.

QoS-oriented media access control using reinforcement learning for next-generation WLANs

Orthogonal frequency division multiple access (OFDMA) is introduced in IEEE 802.11ax to satisfy massive transmission demands. However, the uplink OFDMA-based random access (UORA) mechanism provides poor quality of service (QoS), and restricts channel utilization efficiency, especially in the dynamic network environment. To solve these issues, in this study, the transmission period is decoupled into a contention stage and a transmission stage, and an intelligent media access control (MAC) algorithm with QoS-guaranteed for next-generation wireless local area networks (WLANs) is presented. Specifically, we consider stochastic and various traffic in time-varying wireless communication conditions and propose two contention window (CW) optimization mechanisms based on Q-learning (QL) and a deep Q-network (DQN) (referred to as QL-MAC and DQN-MAC) for static and dynamic network scenarios, respectively. Meanwhile, the access point (AP) acts as the reinforcement learning (RL) agent and centrally optimizes the CW for all stations to eventually maximize the system throughput. Furthermore, we provide the QoS-guaranteed channel access mechanism for different priority data traffic, in which high-priority traffic can obtain more channel access opportunities in the uplink contention stage. Simulation results demonstrate that the proposed algorithms can significantly improve the network performance in terms of convergence, throughput, delay, and fairness compared to the adaptive grouping-based two-stage mechanism (BTM) and double random access QoS-oriented OFDMA MAC (DRA-OFDMA) algorithm in various scenarios.

Node Classification-Based Bandwidth Allocation: A New Scheduling Algorithm for TDMA-Based LANs

Local area networks often comprise nodes that run applications that belong to different traffic classes, with each class having different bandwidth requirements. Traditional Medium Access Control (MAC) protocols treat all nodes in the same manner. This may lead to a disproportionate allocation of bandwidth to the nodes and, consequently, to significant performance degradation. In this paper, a new MAC algorithm, is presented, that allocates different amounts of bandwidth to the nodes according to their traffic class. The bandwidth allocated to the nodes of each traffic class is proportional to the bandwidth requirements of the nodes of that class. The performance of the proposed Node Classification-based Bandwidth Allocation (NCBA) algorithm is studied via extensive simulation results, which indicate that it achieves a significant performance improvement compared to the well-known TDMA scheme. Overall, the new protocol achieves higher throughput, lower delay and exhibits a higher delay Fairness compared to TDMA for various network configurations, under asymmetric bursty traffic.

Performance comparison of IEEE 802.15.4 and IEEE 802.15.4e based MAC algorithm in wireless body sensor networks

One of the potential applications of Wireless Sensor Network for improving the lifestyle of human beings is Wireless Body Sensor Network (WBSN). A dedicated health monitoring system is referred to as the Ubiquitous Health Monitoring (UHM) system consisting of the Internet of Things (IoT) based access points which are made available in a cloud-based server. So, ZigBee based IEEE 802.15.4 technology is extensively used in the implementation of Medium Access Control (MAC) and Physical (PHY) layers. Hence, a comparison is provided in terms of the features of the modified IEEE 802.15.4e standard. An algorithmic approach for the MAC layer helped in regulated power consumption of the sensor node by controlling the transmission power for the packets. This is initiated in the algorithm by categorizing the packets as Delay sensitive and Delay insensitive. By regulating the channel access strategy using Medium Access Control (MAC) layer, the energy consumption of the transceiver reduces, thus improving the energy consumption of the communication system and lifetime of the sensor network. For better throughput using IEEE 802.15.4e, the performance of Deterministic and Synchronous Multi-channel Extension (DSME) is found to be trustworthy than Time Slotted Channel Hopping (TSCH).

A Novel Medium Access Control Algorithm for Ad Hoc Networks Based on Ising Model

Medium Access Control (MAC) scheduling in ad hoc networks is a challenging task due to the trade-offs between fairness, delay and throughput. In this work, we propose a distributed link scheduling algorithm based on the Ising Model from statistical mechanics, by associating a novel Hamiltonian measure with the network such that its optimization yields a feasible schedule. This work overcomes the shortcomings of previous Ising Model based algorithms by incorporating queuing and servicing dynamics as well as fairness measures for improving aggregate throughput and network latency. Our simulations show considerable improvement in performance compared to existing benchmarks over a variety of traffic arrival patterns and network topologies.

Opportunism in Spectrum Sharing for Beyond 5G With Sub-6 GHz: A Concept and Its Application to Duplexing

With the envisioned massive connectivity era, one of the challenges for 5G/Beyond 5G (B5G) wireless systems will be handling the unprecedented spectrum crunch. A potential solution has emerged in the form of spectrum sharing, which deviates from a monopolistic spectrum usage system. This paper investigates the medium access control (MAC) as a means of increasing the viability of the spectrum sharing technique. We first quantify the opportunity of spectrum access in a probabilistic manner, a method referred to as opportunistic (OP) map. Based on the OP framework, we propose a random MAC algorithm in which the access of a node is randomly determined with its own OP value. As a possible application of our OP-map based random MAC, we propose a flexible half-duplex (HD)/full-duplex (FD) communication where each pair decides the duplexing mode according to the OP values of the two pair nodes. This approach fits well with the spectrum sharing system since it enables a flexible operation for the spectrum access according to the spectrum usage level. From the numerical analysis, we validate the feasibility and verify the performance enhancements by implementing a field-programmable gate array (FPGA) based real-time prototype. We further carry out extensive 3D ray-tracing based system-level simulations on investigating the network-level performance of the proposed system. Measurements and numerical results confirm that the proposed architecture can achieve higher system throughput than conventional LTE-TDD (time division duplex) systems.

A vehicle's weight‐based prioritized reciprocity MAC

AbstractIn vehicular ad hoc networks, vehicles compete for channel access through the medium access control protocol to transmit messages. Most traditional medium access methods assign the same probability to all vehicles accessing the channel and ignore the intrinsic attributes of different vehicles. Attributes regarding the position and role of a vehicle are important factors to be considered when a vehicle is competing for the channel. In this paper, we introduce a new notion of a weight factor in a fair medium access game and propose a game model to adjust each node's channel access probability with complete information in the vehicular environment based on the weight factors of vehicles. The weight of a vehicle represents a specific property, such as the distance between vehicles, the vehicle's role, and so on, which can be used to distinguish priorities of different vehicles during channel competition. We also provide instances of relevant applications by using the distance between vehicles and a vehicle's role. Then, we analyze the incomplete information game in which each node cannot acquire the previous channel access probabilities of other nodes. Moreover, we construct a distributed best‐response learning algorithm based on the medium access game model and demonstrate that the game can converge to a unique and stable equilibrium under certain conditions. Furthermore, we investigate some performance indicators such as channel access delay and normalized throughput and perform extensive numerical analyses compared with the IEEE 802.11p protocol and an existing game‐based medium access control algorithm without consideration of weights. The performance comparison of high‐priority nodes and all nodes in a network is also studied. Finally, we analyze the effects of the proportion of high‐priority nodes on the performance of the channel. The performance improvement after introducing the weight factor is verified by these numerical results.

A proposal of novel design on the WAVE MAC algorithm with low-latency for seamless video surveillance in V2X environment

This paper proposed an MAC (Media Access Control) operation method based on the CCH (Control Channel) and SCH (Service Channel) control mode of the WAVE (Wireless Access for Vehicle Environment) network in order to secure service performance sensitive to certain delays with no restriction to services pursued in the present WAVE network. The proposed method configures a new superframe for CCH and SCH frames in the WAVE network defined by IEEE Std. 1609.4 and applies TDM (Time Division Multiplexing) to the CCH frame in order to secure traffic stability and latency minimization in each terminal. CSMA/CA (Carrier Sense Multiple Access/Collision Avoidance) is applied to the SCH frame in order to secure autonomy in service perspectives. Additionally, delay control is secured despite congestion among multiple terminals in V2V communication without a station RSU (Road Side Unit) since the proposed MAC operation method adopts a new CCH/SCH coordination mode for the WAVE network. The proposed method’s applicability is verified as the simulation analysis results showed satisfactory low latency performance.

A Differentiated Reservation MAC Protocol for Achieving Fairness and Efficiency in Multi-Rate IEEE 802.11 WLANs

This paper focuses on designing a medium access control and channel usage algorithm in multi-rate wireless local area networks for improving the efficiency and fairly sharing channel resources among the contending nodes. Aiming for the problems that the high collision is often caused by binary exponential backoff mechanism in the legacy IEEE 802.11 and the shared channel can be overused by low bitrate nodes, we propose a differentiated reservation (DR) algorithm to reduce the collision among the contending nodes by setting their backoff counter as a deterministic value once accessing successfully to the channel. Furthermore, to eliminate the performance anomaly, some nodes are permitted to send multiple packets in one transmission opportunity according to their feature. Moreover, we present the implementation of the DR algorithm that is readily applied to both the existing 802.11 DCF and 802.11e EDCA networks with minimum modification. In addition, we also investigate the limitation of the DR algorithm and propose a group-based differentiated reservation (GDR) algorithm applied to high dense scenarios. The results of the theoretical analysis and simulation validate that our proposed algorithms (DR and GDR) can obtain high throughput, good airtime fairness, and low collision rate.

An Adaptive Beamforming Time with Round-Robin MAC Algorithm for Reducing Energy Consumption in MANET

The use of smart antenna systems (SASs) in mobile ad hoc networks (MANETs) has been promoted as the best choice to improve spatial division multiple access (SDMA) and throughput. Although directional communications are expected to provide great advantages in terms of network performance, directional MAC (medium access control) protocols introduce several issues. One of the most known problems in this context is represented by the fact that, when attempting to solve or at least mitigate the problems introduced by these kinds of antennas especially at MAC layer, a large amount of energy consumption is achieved; for example, due to excessive retransmissions introduced by very frequently issue such as deafness and handoff. The expedients proposed in order to reduce these drawbacks attempting to limit beamforming time of nodes in cooperation with a round-robin scheduling can grant high performance in terms of fairness and throughput. However, the overall energy distribution in the network is not efficient due to static approach. In view of this, we propose adaptive beamforming time with round-robin MAC providing a dynamic assignment of the beamforming time with the aim to limit the waste of energy of nodes. The proposed approach provides benefits in terms of energy consumption distribution among nodes in sectorized antennas environments and, simultaneously, improves MAC packet performance.

Distributed multiple access with a general link layer channel

This paper investigates the problem of distributed medium access control in a time slotted wireless multiple access network with an unknown finite number of homogeneous users. Assume that each user has a single transmission option. In each time slot, a user chooses either to idle or to transmit a packet. Under a general channel model, a distributed medium access control framework is proposed to adapt transmission probabilities of all users to a value that maximizes an arbitrarily chosen symmetric network utility. Probability target of each user in the proposed algorithm is calculated based upon a channel contention measure, which is defined as the success probability of a virtual packet. It is shown that the proposed algorithm falls into the classical stochastic approximation framework with guaranteed convergence when the contention measure can be directly obtained from the receiver. On the other hand, when the contention measure is not directly available, computer simulations show that a revised medium access control algorithm can still help the system to converge to the same designed equilibrium.

Optimal sleep time controller based on traffic prediction and residual energy in duty-cycled wireless sensor networks

In duty-cycled wireless sensor networks, energy efficiency and packet latency are two most important metrics in the design of medium access control and routing algorithms. However, these two problems cannot be addressed well at the same time. In this article, we investigate the trade-off between energy consumption and latency and formulate them into a multi-objective optimization problem. By applying the single exponential smoothing method, we estimate the amount of data of next period and design two optimal sleep time controllers according to time scheduling model of network, so as to dynamically adjust the duty cycle of end node. Our controllers also consider the residual energy of end node. Finally, we propose two dynamic and adaptive medium access control algorithms for synchronous and asynchronous duty-cycled wireless sensor networks, respectively. We evaluate our protocols with different parameters and compare them with existing works. Performance results show that our proposed algorithms can balance power consumption among nodes and improve power efficiency while guaranteeing packet latency is minimized.

Location based transmission using a neighbour aware with optimized EIFS MAC for ad hoc networks

In a typical Ad Hoc network, participating nodes have scarce shared bandwidth and limited battery life resources, so resource optimization and enhancing the overall network performance are the primary aims to maintain functionality. This paper proposes a new cross layer Medium Access Control (MAC) algorithm called Location Based Transmission using a Neighbour Aware with optimized Extended Inter-Frame Spacing (EIFS) for Ad Hoc Networks MAC (LBT-NA with optimized-EIFS MAC) that aims to reduce the transmission power when communicating with the next hop receiver based on node's location which is made available during node deployment. However, node mobility is not taken into account in the study of this paper. According to the algorithm the node dynamically adjusts its transmission power, if there is an active neighbour located beyond the communicating source and destination pair to avoid hidden nodes. The new protocol also defines an optimized EIFS when frame collision, frame error or frame capture takes place, in-order to maintain a fair channel access among the contending nodes. The proposed MAC also uses a modified range of random backoff values, based on the degree of contention unlike IEEE 802.11 series which uses a fixed random backoff value for fresh frames irrespective of the degree of contention. Simulation results indicate that in a random topology with a random source and destination, when the two sources are separated by a minimum distance of 200m, the performance gain of power controlled MAC over IEEE 802.11b ranges from 30% to 70% depending on the type of traffics in the network and the degree of fairness ranges from 62% to 99.99% for a location based MAC with minimum power transmission, whereas LBT-NA with optimized-EIFS MAC secures fairness index ranging from 75% to 99.99%. Communication with a node that is 20m away can save 40% of the battery life in comparison to the traditional transmission power MAC from 802.11b. The validation tests demonstrate that the proposed algorithm increases battery life and reduces the interference impact on shorter distance communication and increases the probability of parallel transmission. The proposed protocol also provides a scope for active nodes to transmit with a higher degree of probability, providing higher degree of overall network throughput in the environment and alleviate the starvation of hidden node by using Dynamic EIFS scheme.

Adaptive Sleep Efficient Hybrid Medium Access Control algorithm for next-generation wireless sensor networks

The scheduling algorithm is a fundamental design problem to allocate resources amongst different entities in distributive wireless sensor networks (WSNs). These sensor nodes have limited power and non-replenishable energy resources. In WSNs, the duty cycling mechanism is commonly used to save energy due to idle listening. On the other hand, a fixed duty cycling mechanism increases transmission latency in WSNs. Therefore, in order to ensure the prolonged network-life of WSNs, the medium access control (MAC) protocol should be tackled in an efficient manner to improve energy efficiency by minimizing idle listening, maximizing sleep duration, and eliminating data collision. This paper proposes a practical Adaptive Sleep Efficient Hybrid Medium Access Control (AEH-MAC) algorithm in which the key idea is to dynamically adjust nodes’ sleep time to improve the scheduling in WSNs. The AEH-MAC allows nodes to adjust sleep time dynamically according to the traffic load and coordinate wakeup time with neighbour nodes. A series of short taken packets are transmitted to wake the receiver, and a prediction field is introduced in the ACK packets (GRANT/RELEASE) to reduce the waiting time of the source node. In the proposed algorithm, each node maps a conflict-free time slot for itself up to two-hop neighbouring nodes. The simulation results show that the AEH-MAC algorithm achieves high performance in terms of runtime, number of rounds, energy consumption, and slot reservation.

Tree TDMA MAC Algorithm Using Time and Frequency Slot Allocations in Tree-Based WSNs

In this paper, we propose a tree-based time division multiple access (Tree TDMA) media access control (MAC) algorithm based on the IEEE 802.15.4 PHY standard. The method involves the simultaneous use of two algorithms, a time slot allocation algorithm (TSAA) and a frequency slot allocation algorithm (FSAA), at low power consumption to support voice and data communication to solve the problems afflicting prevalent MAC protocols in tree topology networks. The TSAA first generates routing paths through the control channel in a super frame prior to transmitting packets, and allocates time slots for each node to transmit packets. The FSAA then allocates frequencies to each path according to the routing paths generated following its application. The overhearing problem and the funneling effect in TDMA as well as carrier sense multiple access with collision avoidance (CSMA/CA) MACs are resolved by these two algorithms because a given node and its neighbors are orthogonal in terms of time and frequency. The problem of inter-node synchronization is addressed by periodically sending a beacon from higher to lower nodes, and the issue of low power is solved by leaving unsigned time slots in an idle state. To test the effectiveness of the proposed algorithm, we used a MATLAB simulation to compare its performance with that of contention-based CSMA MAC and non-contention-based TreeMAC in terms of network throughput, network delay, energy efficiency, and energy consumption. We also tested the performance of the algorithms for increasing number of nodes and transmission packets in the tree topology network.

ResVMAC: A Novel Medium Access Control Protocol for Vehicular Ad hoc Networks

Abstract: Efficient medium access control (MAC) is a key part of any wireless network communication architecture. MAC protocols are needed for nodes to access the shared wireless medium efficiently. Vehicular Ad hoc networks (VANETs) are an emerging network technology on the verge of large-scale deployment. The dynamic network topologies in VANETs caused by high mobility rates of vehicles presents a great challenge in reliable data transfer. A MAC protocol that enables quick reservation of packet transmission slots by vehicles that wish to send packets is crucial in addressing this challenge. In this paper, we propose a new distributed MAC algorithm ResVMAC for VANETs. We demonstrate using simulations, that our algorithm outperforms two state-of-the-art algorithms in key performance metrics.

Real‐world testbed for multi‐tag UWB chipless RFID system based on a novel collision avoidance MAC protocol

ABSTRACTChipless radio frequency identification (RFID) tags are dummy, memoryless, with limited number of bits, very low backscattered power, and short reading range. Therefore, the existing RFID standards and protocols designed for the chipped RFID systems are not applicable for the chipless systems. Main objective of this contribution is to introduce a novel real‐world testbed for multi‐tag ultra‐wideband (UWB) chipless RFID system. In this testbed, a new Notch Position Modulation scheme is implemented as the first medium access control algorithm for handling the multi‐tag identification scenario of the frequency signature based chipless RFID tags. This intelligent Notch Position Modulation algorithm reduces the sensing and identification time and accordingly the overall system latency. The proposed protocol enables fetching the frequency signatures of the chipless RFID tags through the whole UWB range effectively. Moreover, an advanced signaling scheme is designed for the RFID reader in order to make the best use of the Federal Communications Commission UWB regulations for increasing the maximum transmitted power and the corresponding reading range. The signaling scheme, real‐time channel estimation, and clutter removal technique are implemented on the software defined radio platform in a heavily dense multipath indoor environment. Based on the medium access control protocol, the mitigation of the undesired environmental reflections as well as the interference between the chipless RFID tags is well demonstrated in the developed testbed.

Pliable Cognitive MAC for Heterogeneous Adaptive Cognitive Radio Sensor Networks.

The rapid expansion of wireless monitoring and surveillance applications in several domains reinforces the trend of exploiting emerging technologies such as the cognitive radio. However, these technologies have to adjust their working concepts to consider the common characteristics of conventional wireless sensor networks (WSNs). The cognitive radio sensor network (CRSN), still an immature technology, has to deal with new networks that might have different types of data, traffic patterns, or quality of service (QoS) requirements. In this paper, we design and model a new cognitive radio-based medium access control (MAC) algorithm dealing with the heterogeneous nature of the developed networks in terms of either the traffic pattern or the required QoS for the node applications. The proposed algorithm decreases the consumed power on several fronts, provides satisfactory levels of latency and spectrum utilization with efficient scheduling, and manages the radio resources for various traffic conditions. An intensive performance evaluation is conducted to study the impact of key parameters such as the channel idle time length, node density, and the number of available channels. The performance evaluation of the proposed algorithm shows a better performance than the comparable protocols. Moreover, the results manifest that the proposed algorithm is suitable for real time monitoring applications.