Medium Access Control Protocol Design Research Articles

A MAC Protocol Design for Maximizing End-to-End Throughput and Fairness Guarantee in Chain-Based Multi-Hop Wireless Backhaul Networks

Chain-based multi-hop wireless backhaul networks (WBN) have attracted considerable attention in next-generation networks since it can cost-effectively extend the service coverage area. The major challenge pertaining to such networks is the designing of a high-performance medium access control (MAC) scheme to raise the end-to-end throughput and ensure fairness. In this paper, we propose a novel MAC protocol, that is aimed at resolving the well-known location-dependent unfairness problem of chain-based networks, maximizing spatial reuse, and most importantly, achieving exceptional end-to-end throughput. Our scheme provides an elaborate control mini-slots design that resolves the different relay-traffic load problem of nodes at various positions near or far from the gateway and further provides local-traffic fairness among all nodes. Moreover, based on the traffic analysis, we provide a four-node group-transmission methodology. By using the neighbor-nodes echoes (broadcasts) the reservation-signals design, the chain-based WBN is allowed to extend to numerous nodes for concurrent and collision-free data transmission through distributed scheduling. Extensive simulation and analytic results also demonstrate that our proposed MAC scheme achieves exceptional system throughput which is approximately 1.6 times better than previous works for a four-node-chain network and also attains high system performance under a wide range of traffic loads and various system parameters.

Analyzing the impact of medium access control protocol design and control-plane uplink in asymmetric RF/OWC networks with RF congestion

As the demand for wireless capacity continues to grow, highly directional wireless communication technologies have the potential to provide massive gains in area spectral efficiency. However, novel challenges arise when considering bidirectional connectivity and multi-cell/multi-user systems with highly directional links. Some of these challenges can be alleviated with the introduction of asymmetric connectivity where the highly directional links are used solely for downlink transmission. As an example, we consider asymmetric links with an optical wireless communication (OWC) downlink and sub-6 GHz RF uplink. More specifically, we consider visible light communication as an instance of OWC, although the presented analysis and validation are applicable to alternative OWC technologies and other simplex downlink transmission technologies. While asymmetric connectivity has been previously demonstrated in scenarios like this, the impact of control-plane asymmetry has not been explored, to our knowledge. In this paper, we first introduce the novel challenges related to local handshaking in wireless networks with control-plane asymmetry. We then develop a theoretical framework for throughput analysis in a network where the sub-6 GHz RF channel is shared between a conventional RF link and an asymmetric RF/OWC link. This analysis is validated via simulation and verified in a testbed system using Mango WARP3 software defined radios and a commercially available RF access point. Finally, we use the derived throughput equations to analyze the impact of various protocol parameters and demonstrate one potential use of the derived equations to evaluate sum throughput in the presence of an unreliable OWC link.

Data concurrent transmission MAC protocol for application oriented underwater acoustic sensor networks

With the increasing demand for marine exploration, underwater acoustic sensor networks (UASNs) are prone to have the characteristics of large-scale, long term monitoring, and high data traffic load. Underwater media access control (MAC) protocols, which allow multiple users to share the common medium fairly and efficiently, are essential for the performance of UASNs. However, the design of MAC protocols is confronted with the challenges of spatial unfairness, data eruption, and low energy efficiency. In this paper, we propose a novel data concurrent transmission (DCT) MAC protocol, which is able to exploit long propagation delay and conduct concurrent transmission. Specifically, we present the theoretical performance analysis of the proposed MAC protocol in detail and give an analytical solution of the success concurrent transmission probability between nodes. In addition, simulation results are provided to demonstrate that our proposed protocol is appropriate for UASNs and can significantly improve the performance in terms of network throughput and energy consumption. Finally, we give some typical future applications of UASNs and discuss the demands on MAC protocol design.

Medium access control protocol design for wireless communications and networks review

<p><span>Medium access control (MAC) protocol design plays a crucial role to increase the performance of wireless communications and networks. The channel access mechanism is provided by MAC layer to share the medium by multiple stations. Different types of wireless networks have different design requirements such as throughput, delay, power consumption, fairness, reliability, and network density, therefore, MAC protocol for these networks must satisfy their requirements. In this work, we proposed two multiplexing methods for modern wireless networks: Massive multiple-input-multiple-output (MIMO) and power domain non-orthogonal multiple access (PD-NOMA). The first research method namely Massive MIMO uses a massive number of antenna elements to improve both spectral efficiency and energy efficiency. On the other hand, the second research method (PD-NOMA) allows multiple non-orthogonal signals to share the same orthogonal resources by allocating different power level for each station. PD-NOMA has a better spectral efficiency over the orthogonal multiple access methods. A review of previous works regarding the MAC design for different wireless networks is classified based on different categories. The main contribution of this research work is to show the importance of the MAC design with added optimal functionalities to improve the spectral and energy efficiencies of the wireless networks.</span></p>

An Analysis on Contemporary MAC Layer Protocols in Vehicular Networks: State-of-the-Art and Future Directions

Traffic density around the globe is increasing on a day-to-day basis, resulting in more accidents, congestion, and pollution. The dynamic vehicular environment induces challenges in designing an efficient and reliable protocol for communication. Timely delivery of safety and non-safety messages is necessary for traffic congestion control and for avoiding road mishaps. For efficient resource sharing and optimized channel utilization, the media access control (MAC) protocol plays a vital role. An efficient MAC protocol design can provide fair channel access and can delay constraint safety message dissemination, improving road safety. This paper reviews the applications, characteristics, and challenges faced in the design of MAC protocols. A classification of the MAC protocol is presented based on contention mechanisms and channel access. The classification based on contention is oriented as contention-based, contention-free, and hybrid, whereas the classification based on channel access is categorized as distributed, centralized, cluster-based, cooperative, token-based, and random access. These are further sub-classified as single-channel and multi-channel, based on the type of channel resources they utilize. This paper gives an analysis of the objectives, mechanisms, advantages/disadvantages, and simulators used in specified protocols. Finally, the paper concludes with a discussion on the future scope and open challenges for improving the MAC protocol design.

Energy-Efficient Collision Avoidance MAC Protocols for Underwater Sensor Networks: Survey and Challenges

The Medium Access Control (MAC) layer protocol is the most important part of any network, and is considered to be a fundamental protocol that aids in enhancing the performance of networks and communications. However, the MAC protocol’s design for underwater sensor networks (UWSNs) has introduced various challenges. This is due to long underwater acoustic propagation delay, high mobility, low available bandwidth, and high error probability. These unique acoustic channel characteristics make contention-based MAC protocols significantly more expensive than other protocol contentions. Therefore, re-transmission and collisions should effectively be managed at the MAC layer to decrease the energy cost and to enhance the network’s throughput. Consequently, handshake-based and random access-based MAC protocols do not perform as efficiently as their achieved performance in terrestrial networks. To tackle this complicated problem, this paper surveys the current collision-free MAC protocols proposed in the literature for UWSNs. We first review the unique characteristic of underwater sensor networks and its negative impact on the MAC layer. It is then followed by a discussion about the problem definition, challenges, and features associated with the design of MAC protocols in UWANs. Afterwards, currently available collision-free MAC design strategies in UWSNs are classified and investigated. The advantages and disadvantages of each design strategy along with the recent advances are then presented. Finally, we present a qualitative comparison of these strategies and also discuss some possible future directions.

FD MAC Protocol Design for Co-Existing WLANs in 5G Cellular Networks

Abstract In this paper, we design full-duplex (FD) medium access control (MAC) protocol for co-existing wireless local area networks (WLANs) in 5G cellular networks (WCFD-MAC). Our design considers some significant features of 5G networks, exceptionally, beamforming and FD capabilities at both, the base station and user equipment. FD communications may generate interferences, namely self-interference (SI) in bidirectional FD (BFD) and inter-user interferences in three-node FD (TNFD). Several efforts have been performed to mitigate the SI in BFD communications. However, the inter-user interferences in TNFD are still considered as a major drawback in FD networks. These interferences must be mitigated by an efficient MAC protocol design. WCFD-MAC protocol allows two neighboring users to simultaneously participate in TNFD communication without interfering with each other by using directional transmission and a three-node angle condition (TAC). Directional transmission combined with TAC increases system throughput. WCFD-MAC protocol allows a new half-duplex (HD) communication scheme referred to as three-node HD (TNHD). This scheme may occur when bidirectional FD (BFD) and TNFD communications cannot occur. TNHD scheme includes device-to-device (D2D) communication and allows energy efficiency, which is one of the keys requirements of 5G wireless networks. Simulations results show that WCFD-MAC protocol achieves higher throughput than existing works in the literature.

Medium Access Control Protocols for Flying Ad Hoc Networks: A Review

Recently, flying ad hoc networks (FANETs) have been broadly applied to various civilian and military applications. Medium access control (MAC) protocols have attracted significant attention because of their impact on overall network performance. Owing to peculiar features such as high mobility and dynamic topology, however, the design of a MAC protocol for FANETs confronts challenges. Several MAC protocols for FANETs have been reported in literature. In early MAC protocols for FANETs, delay, throughput, and collision detection were the key design concerns. Recently, however, the design of an energy-efficient MAC protocol has become a new research focus. To the best of the authors’ knowledge, there exists no survey on MAC protocols for FANETs. This study extensively investigates the existing MAC protocols for FANETs. In this paper, the MAC design issues in FANETs are presented first. Subsequently, the existing MAC protocols are reviewed and discussed from the perspective of major features, operational principles, advantages, and limitations. The MAC protocols are then qualitatively compared in terms of major features, characteristics, and performance factors. Furthermore, open issues and research challenges are summarized and discussed.

Preamble time-division multiple access fixed slot assignment protocol for secure mobile ad hoc networks

Mobile ad hoc networks are the “spontaneous networks” which create a temporary network in any place and any time without using any extra fixed radio device of a full infrastructure network. Each device in this network works as a router to develop end-to-end communication connections and move independently in any direction. Mostly, mobile ad hoc networks use the IEEE 802.11b protocol with carrier-sense multiple access with collision avoidance medium access control layer protocol for sharing a common medium among the nodes simultaneously. Due to this distributed medium, the routing and medium access control layer of the mobile ad hoc network are prone to attacks. Among several attackers, blackhole attacker is the dangerous one which causes the loss of all data packets of devices in the network. Efficient medium access control protocol designs in this respect play a key role in determining channel utilization, network delay, and, more importantly, network security. In the proposed work, preamble information is used with time-division multiple access medium access control. The preamble time-division multiple access uses time synchronization for each time slot and does not assign much time to the blackhole attacker due to a fixed time slot. As a result, blackhole is not stable in all communications and such an attack is effectively defended. Simulation results show that, in the presence of the blackhole attacker, carrier-sense multiple access with collision avoidance has a high packet loss ratio and low network throughput as compared to the proposed preamble time-division multiple access.

Fast node cardinality estimation and cognitive MAC protocol design for heterogeneous machine-to-machine networks

Machine-to-Machine (M2M) networks are an emerging technology with applications in numerous areas including smart grids, smart cities, vehicular telematics, and healthcare. In this paper, we design two estimation protocols for rapidly obtaining separate estimates of the number of active nodes of each traffic type in a heterogeneous M2M network with $T$ types of M2M nodes (e.g., those that send emergency, periodic, normal type data etc), where $T \geq 2$ is an arbitrary integer. One of these protocols, Method I, is a simple scheme, and the other, Method II, is more sophisticated and performs better than Method I. Also, we design a medium access control (MAC) protocol that supports multi-channel operation for a heterogeneous M2M network with an arbitrary number of types of M2M nodes, operating as a secondary network using Cognitive Radio technology. Our Cognitive MAC protocol uses the proposed node cardinality estimation protocols to rapidly estimate the number of active nodes of each type in every time frame; these estimates are used to find the optimal contention probabilities to be used in the MAC protocol. We compute a closed form expression for the expected number of time slots required by Method I to execute as well as a simple upper bound on it. Also, we mathematically analyze the performance of the Cognitive MAC protocol and obtain expressions for the expected number of successful contentions per frame and the expected amount of energy consumed. Finally, we evaluate the performances of our proposed estimation protocols and Cognitive MAC protocol using simulations.

RPCP‐MAC: Receiver preambling with channel polling MAC protocol for underwater wireless sensor networks

SummaryTo design a reliable and energy efficient medium access control (MAC) protocol for underwater wireless sensor networks (UWSNs) is an active research area due to its variety of applications. There are many issues associated with underwater acoustic channels including long and variable propagation delay, attenuation, and limited bandwidth which pose significant challenges in the design of MAC protocol. The available sender‐initiated asynchronous preamble‐based MAC protocols for UWSNs are not reliable and energy‐efficient. This is due to the problems caused by transmission of preambles for longer duration and collision of preambles from hidden nodes in sender‐initiated preamble‐based MAC protocols. To resolve these issues, the paper proposed an asynchronous receiver‐initiated preamble‐based MAC protocol named Receiver Preambling with Channel Polling MAC (RPCP‐MAC) protocol for shallow underwater monitoring applications with high data rates. The protocol is proposed to resolve data packet collision and support reliability in an energy‐efficient way without using any transmission schedule. The proposed protocol is based on the following mechanisms. Firstly, receiver preambling mechanism is adopted to reduce idle listening. Secondly, channel polling mechanism is used to determine missing data frame during its sleeping period and to minimize the active time of node and reduces energy wastage. Finally, a back‐off mechanism is applied to resolve collision when preambles are received simultaneously. In addition, performance analysis through Markov chain together with its validation with simulation‐based studies is reported in the paper. Both the analytical and simulation results have demonstrated the reliability achievable with RPCP‐MAC while providing good energy efficiency.

Mobility Aware Co-operative MAC Protocol for Reliable Transmission in VANET

The Medium Access Control (MAC) etiquette is liable for partaking the communal medium amongst the competing nodules. The unique characteristics of VANET enforce many restrictions onto the MAC protocol design. The main aims of a VANET MAC protocol are fairness, Quality of Service (QoS), reliability and so on. In case of V2V communication in VANET, if the target vehicle is not reachable, then packets may not be transmitted correctly. In this paper, a Mobility Aware Cooperative MAC protocol (MAC-MAC) for successful transmission in VANET is proposed. In this protocol, when data is transmitted from V2V, the packet error rate (PER) and packet delivery ratio (PDR) metrics are checked at the receiver end. Depending on these values, the transmission mode of the source is changed as DIRECT or COOPERATIVE. In cooperative mode, the source selects the potential relay nodes based on the residence time and distance to the receiver. By experimental results, it is shown that the proposed MAC-MAC protocol has reduced packet drops, delay and overhead with increased packet delivery ratio.

Performance of low level protocols in high traffic wireless body sensor networks

The rapid development of medical sensors has increased the interest in Wireless Body Area Network (WBAN) applications where physiological data from the human body and its environment is gathered, monitored, and analyzed to take the proper measures. In WBANs, it is essential to design MAC protocols that ensure adequate performance and Quality of Service (QoS). This paper investigates Medium Access Control (MAC) protocols used in WBAN, and compares their performance in a high traffic environment with respect to different QoS and network performance metrics. Such scenario can be induced in case of emergency for example, where physiological data collected from all sensors on human body should be sent simultaneously to take appropriate action. This study can also be extended to cover collaborative WBAN systems where information from different bodies is sent simultaneously leading to high traffic. OPNET simulations are performed to compare the performance of the different MAC protocols under the same experimental conditions. A new MAC scheme aiming to enhance the delay, throughput, and energy performance of the system is then proposed and compared to existing protocols, to evaluate its performance in high traffic environment.

SAFE-MAC: Speed Aware Fairness Enabled MAC Protocol for Vehicular Ad-hoc Networks.

Highly dynamic geographical topology, two-direction mobility, and varying traffic density can lead to fairness issues in Vehicular Ad-hoc Networks (VANETs). The Medium Access Control (MAC) protocol plays a vital role in sharing the common wireless channel efficiently between vehicles in a VANET system. However, ensuring fairness between vehicles can be a challenge in designing MAC protocols for VANET systems. The existing protocol, IEEE 802.11 DCF, ensures that the packet transmission rate for a particular vehicle is directly proportional to the amount of time a vehicle spends within a service area, but it does not guarantee that faster vehicles will be able to send the minimum number of packets. Other existing MAC protocols based on IEEE 802.11 are able to provide a minimum amount of data transmission regardless of velocity, but are unable to provide an amount of data transmission that is more proportionate to the time a vehicle spends in the service area. To address the above limitations, we propose a Speed Aware Fairness Enabled MAC (SAFE-MAC) protocol that calculates the residence time of a vehicle in a service area by using mobility metrics such as position, direction, and speed to synthesize the transmission probability of each individual vehicle with respect to its residence time. This is achieved by dynamically altering the values of parameters such as minimum contention window, maximum backoff stage, and retransmission limit in the MAC protocol. We then develop an analytical model to compare the performance of our proposed protocol with contemporary MAC protocols. Numerical analysis results show that our proposed protocol significantly improves fairness among the speed-varying vehicles in VANET.

Review and Evaluation of MAC Protocols for Satellite IoT Systems Using Nanosatellites.

Extending the internet of things (IoT) networks to remote areas under extreme conditions or for serving sometimes unpredictable mobile applications has increased the need for satellite technology to provide effective connectivity. However, existent medium access control (MAC) protocols deployed in commercial satellite networks were not designed to offer scalable solutions for the increasing number of devices predicted for IoT in the near future, nor do they consider other specific IoT characteristics. In particular, CubeSats—a low-cost solution for space technology—have the potential to become a wireless access network for the IoT, if additional requirements, including simplicity and low demands in processing, storage, and energy consumption are incorporated into MAC protocol design for satellite IoT systems. Here we review MAC protocols employed or proposed for satellite systems and evaluate their performance considering the IoT scenario along with the trend of using CubeSats for IoT connectivity. Criteria include channel load, throughput, energy efficiency, and complexity. We have found that Aloha-based protocols and interference cancellation-based protocols stand out on some of the performance metrics. However, the tradeoffs among communications performance, energy consumption, and complexity require improvements in future designs, for which we identify specific challenges and open research areas for MAC protocols deployed with next low-cost nanosatellite IoT systems.

State‐of‐charge estimation to improve decision making by MAC protocols used in WSNs

Energy conservation is a topic of great interest in wireless sensor networks (WSNs). Various techniques have been proposed to minimise the energy consumption. One approach is to design medium access control (MAC) protocols capable of adjusting the sensor node cycle according to the available energy in the battery. The state of charge (SOC) is an indicator of the available energy stored in the battery before discharging. This work proposes a simplified battery model to estimate the SOC and compares the accuracy and computational load of the algorithm as metrics for the implementation of the MAC protocol design.

Exploiting Group Structure in MAC Protocol Design for Multichannel Ad Hoc Cognitive Radio Networks

The design of an efficient medium access control (MAC) protocol for multichannel ad hoc cognitive radio networks is an important problem and has been the topic of extensive recent research. In this paper, we present the design and performance evaluation of a protocol, group MAC (GMAC), which is customized for a situation that commonly arises in ad hoc networks: The network consists of multiple groups of nodes such that a large fraction of the traffic of each node needs to be sent to other nodes of its own group. Some examples are 1) units (e.g., platoons) in a military ad hoc network; 2) divisions in an emergency or disaster relief network; and 3) departments in a corporate or university network. Our protocol requires each secondary node to have only one narrowband transceiver, does not rely on a control channel, and incorporates a novel technique for dynamically balancing the traffic load of secondary nodes across the set of free channels. We formulate the problem of partitioning the network nodes into groups based on the volumes of data traffic to be sent between different pairs of nodes, which we call the group formation problem (GFP). We show that the GFP is NP-complete and propose a greedy algorithm to solve it. We analyze the stability region of the GMAC protocol using a queuing theoretic framework. Our extensive simulations show that a large fraction of the bandwidth unoccupied by primary users is utilized by the GMAC protocol for data transmissions.

MAC protocols with dynamic interval schemes for VANETs

Under the dynamically changing topology of Vehicular Ad-hoc NETworks (VANETs), the restricted intervals in Medium Access Control (MAC) protocols cannot provide sufficient capacity to carry both safety and non-safety applications. One approach which can solve these issues is a dynamic MAC protocol that can adapt itself to the vehicle density or traffic conditions. In this survey, we, therefore, study various techniques for dynamic intervals used in MAC protocols, their advantages, and disadvantages. First, we classify these protocols into three following categories: 1) contention-based, 2) contention-free, and 3) a hybrid between contention-free and contention-based medium access methods. Second, in each medium access method, we classify the methodologies depending on their operating principles. The conclusions of our study are as follows: 1) Adaptive MAC protocols improve the channel utilization and adapt themselves to various traffic states, 2) Adaptive MAC protocols perform better than protocols using fixed intervals, 3) Currently, MAC protocols using dynamic intervals, which are suitable to VANET standards, are only applicable to optimize control channel interval; therefore, it is necessary to expand to both optimize control channel interval and service channel interval according to network and traffic condition. Finally, we discuss some open issues and whether designing MAC protocols using dynamic intervals can meet the QoS requirements for different applications in the future.

Energy-Efficient Medium Access Control Protocols for Cognitive Radio Sensor Networks: A Comparative Survey.

The increase of application areas in wireless sensor networks demands novel solutions in terms of energy consumption and radio frequency management. Cognitive radio sensor networks (CRSNs) are key for ensuring efficient spectrum management, by making it possible to use the unused licensed frequency spectrum together with the unlicensed frequency spectrum. Sensor nodes powered by energy-constrained batteries necessarily require energy-efficient protocols at the routing and medium access control (MAC) layers. In CRSNs, energy efficiency is more important because the sensor nodes consume additional energy for spectrum sensing and management. To the best of authors’ knowledge, there is no survey on “energy-efficient” MAC protocols for CRSNs in the literature, even though a conceptual review on MAC protocols for CRSNs was presented at a conference recently. In this paper, energy-efficient MAC protocols for CRSNs are extensively surveyed and qualitatively compared. Open issues, and research challenges in the design of MAC protocols for CRSNs, are also discussed.

Design and Performance Analysis of Cognitive WLAN MAC Protocol

Cognitive radio networks (CRN) rely upon dynamic spectrum access that allows spectrum to be used efficiently. The role of the medium access control (MAC) protocol in CRN is to distribute efficiently the spectrum among the users. We propose a MAC protocol for cognitive wireless local area network (WLAN) that allows an unlicensed secondary user (SU) to opportunistically access and transmit data on the licensed channel owned by the primary user (PU). The proposed MAC protocol is an adaptation of IEEE 802.11 distributed coordination function. Extensive performance evaluation of the cognitive WLAN MAC protocol has been carried out as follows. First, a Markov chain model of the cognitive WLAN MAC protocol is developed. By solving our model we derive saturated throughput, packet delay, channel busy probability, conditional collision probability of SU, and interference to PU. Extension of our model for the case of multiple PUs under lightly loaded condition is also carried out. Further, we analyze the energy efficiency of the cognitive WLAN MAC protocol. We calculate the optimal sensing time interval for the SUs and the corresponding sensing energy incurred by the SUs. Effect of imperfect channel sensing on the performance of the proposed protocol is investigated. We validate our model by comparing the analytical results with simulation.