Medium Access Control Performance Research Articles

Cooperative optimization techniques in distributed MAC protocols – a survey

Purpose Cross-layer approach in media access control (MAC) layer will address interference and jamming problems. Hybrid distributed MAC can be used for simultaneous voice, data transmissions in wireless sensor network (WSN) and Internet of Things (IoT) applications. Choosing the correct objective function in Nash equilibrium for game theory will address fairness index and resource allocation to the nodes. Game theory optimization for distributed may increase the network performance. The purpose of this study is to survey the various operations that can be carried out using distributive and adaptive MAC protocol. Hill climbing distributed MAC does not need a central coordination system and location-based transmission with neighbor awareness reduces transmission power. Design/methodology/approach Distributed MAC in wireless networks is used to address the challenges like network lifetime, reduced energy consumption and for improving delay performance. In this paper, a survey is made on various cooperative communications in MAC protocols, optimization techniques used to improve MAC performance in various applications and mathematical approaches involved in game theory optimization for MAC protocol. Findings Spatial reuse of channel improved by 3%–29%, and multichannel improves throughput by 8% using distributed MAC protocol. Nash equilibrium is found to perform well, which focuses on energy utility in the network by individual players. Fuzzy logic improves channel selection by 17% and secondary users’ involvement by 8%. Cross-layer approach in MAC layer will address interference and jamming problems. Hybrid distributed MAC can be used for simultaneous voice, data transmissions in WSN and IoT applications. Cross-layer and cooperative communication give energy savings of 27% and reduces hop distance by 4.7%. Choosing the correct objective function in Nash equilibrium for game theory will address fairness index and resource allocation to the nodes. Research limitations/implications Other optimization techniques can be applied for WSN to analyze the performance. Practical implications Game theory optimization for distributed may increase the network performance. Optimal cuckoo search improves throughput by 90% and reduces delay by 91%. Stochastic approaches detect 80% attacks even in 90% malicious nodes. Social implications Channel allocations in centralized or static manner must be based on traffic demands whether dynamic traffic or fluctuated traffic. Usage of multimedia devices also increased which in turn increased the demand for high throughput. Cochannel interference keep on changing or mitigations occur which can be handled by proper resource allocations. Network survival is by efficient usage of valid patis in the network by avoiding transmission failures and time slots’ effective usage. Originality/value Literature survey is carried out to find the methods which give better performance.

An Adaptive and Spectrally Efficient Multi-Channel Medium Access Control Protocol for Dynamic Ad Hoc Networks.

Medium access control (MAC) protocols in ad hoc networks have evolved from single-channel independent transmission mechanisms to multi-channel concurrent mechanisms to efficiently manage the demands placed on modern networks. The primary aim of this study is to compare the performance of popular multi-channel MAC (MMAC) protocols under saturated network traffic conditions and propose improvements to the protocols under these conditions. A novel, dynamically adaptive MMAC protocol was devised to take advantage of the performance capabilities of the evaluated protocols in changing wireless ad hoc network conditions. A simulation of the familiar MAC protocols was developed based on a validated simulation of the IEEE 802.11 standard. Further, the behaviors and performances of these protocols are compared against the proposed MMAC protocols with a varying number of ad hoc stations and concurrent wireless channels in terms of throughput, Jain's fairness index, and channel access delay. The results show that the proposed MMAC protocol, labeled E-SA-MMAC, outperforms the existing protocols in throughput by up to 11.9% under a constrained number of channels and in channel access delays by up to 18.3%. It can be asserted from these observations that the proposed approach provides performance benefits against its peers under saturated traffic conditions and other factors, such as the number of available wireless channels, and is suitable for dynamic ad hoc network deployments.

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.

Multi-objective cooperative medium access control protocols in wireless Ad-Hoc networks

Relay-based cooperative communications have been emerging as a novel paradigm in many wireless protocols. The IEEE 802.11 medium access control (MAC) protocols have attracted many cooperative techniques. The relay selection algorithms have a remarkable influence on the design and the performance of the cooperative MAC (CMAC) protocols. Most of the existing algorithms have been designed based on a single objective such as spectrum efficiency and energy efficiency. In this paper, two multi-objective CMAC protocols are proposed: FCGMAC and EECMAC. The FCGMAC employs a multiple relay selection algorithm providing the spectrum efficiency and fairness. The EECMAC exploits a single relay selection improving the energy efficiency and the spectrum efficiency. The proposed protocols have been simulated in the ns-3 network simulator and the simulation results indicate the improvement of network performance according to the design objectives.

MAC for Machine-Type Communications in Industrial IoT—Part I: Protocol Design and Analysis

In this two-part paper, we propose a novel medium access control (MAC) protocol for machine-type communications in the Industrial Internet of Things. The considered use case features a limited geographical area and a massive number of devices with sporadic data traffic and different priority types. We target supporting the devices while satisfying their Quality-of-Service (QoS) requirements with a single access point and a single channel, which necessitates a customized design that can significantly improve the MAC performance. In Part I of this paper, we present the MAC protocol that comprises a new slot structure, corresponding channel access procedure, and mechanisms for supporting high device density and providing differentiated QoS. A key idea behind this protocol is sensing-based distributed coordination for significantly improving channel utilization. To characterize the proposed protocol, we analyze its delay performance based on the packet arrival rates of devices. The analytical results provide insights and lay the groundwork for the fine-grained scheduling with QoS guarantee as presented in Part II.

A Cross-Layered Theoretical Model of IEEE 1901 Power-Line Communication Networks Considering Retransmission Protocols

Power-line communication (PLC) is a promising communication technology of constructing IoT (internet of things) systems, and it employs IEEE 1901 as its medium access control (MAC) protocol. Current studies about IEEE 1901 MAC performance analysis do not consider the influence of physical layer’s retransmission protocols, i.e., ARQ (automatic repeat request) and HARQ-CC (hybrid ARQ with chase combining). Moreover, how 1901 protocol affect the energy consumption in PLC networks, and whether 1901 protocol has bound performance are also unsolved in these existing works. Focusing on the above problems, we put forward a cross-layered theoretical model to insightfully analyze 1901 protocol, where the impacts of physical layer’s retransmission protocols (ARQ and HARQ-CC), channel fading modes and practical configurations (buffer size, finite traffic load, etc.) are comprehensively taken into consideration in the modeling process. On this basis, we derive the closed-form expressions of 1901 MAC metrics considering retransmission protocols. Furthermore, we construct an energy consumption model, and provide the bound performance analysis for 1901 protocol. Finally, we evaluate the performance of 1901 protocol under different retransmission protocols and system parameters, and verify the proposed cross-layered theoretical model.

MAC Performance Analysis for Reliable Power-Line Communication Networks with ARQ Scheme.

Power-line communication (PLC) networks have been increasingly used for constructing industrial IoT (internet of things) and home networking systems due to their low-cost installation and broad coverage feature. To guarantee the transmission reliability, ARQ (automatic repeat request) scheme is introduced into the link layer of reliable PLC networks, which allows the retransmission of a data frame several times so that it has a higher probability to be correctly received. However, current studies of performance analysis for PLC MAC (medium access control) protocol (i.e., IEEE 1901) do not take into account of the impact of ARQ scheme. To resolve this problem, we propose an analytical model to investigate the MAC performance of IEEE 1901 protocol for reliable PLC networks with ARQ scheme. In the modeling process, we first establish a PLC channel model to reflect the impacts of PLC channel types (containing Rayleigh fading and Log-normal fading), additive non-Gaussian noise feature and ARQ scheme on data transmission at link layer. Next, we employ Renewal theory and Queueing dynamics to capture the transmission attempt behavior of executing IEEE 1901 protocol in the unsaturated environment with finite transit buffer size. On the basis of combining these two models, we derive the closed-form expressions of 1901 MAC metrics considering the influence of the ARQ scheme. Furthermore, we prove that the proposed analytical model has the convergence property. Finally, we evaluate the MAC performance of 1901 protocol for reliable PLC networks with ARQ scheme and verify the proposed analytical model.

Review of MAC Protocols for Vehicular Ad Hoc Networks.

Vehicular ad hoc networks (VANETs) need to support the timely end-to-end transmissions of safety and non-safety messages. Medium access control (MAC) protocols can ensure fair and efficient sharing of channel resources among multiple vehicles for VANETs, which can provide timely packet transmissions and significantly improve road safety. In this paper, we review the standards of some countries for VANETs. Then, we divide the MAC protocols proposed for VANETs into single-channel MAC protocols and multi-channel MAC protocols according to the number of physical occupied spectrum resources. Both are further discussed based on their hierarchical structures, i.e., distributed and centralized structures. General design and optimization mechanisms of these commonly used MAC protocols for VANETs are reviewed. From the viewpoint of 7 aspects, we compare the advantages and disadvantages of these typical MAC protocols. Finally, we discuss the open issues to improve the MAC performance and future work on MAC design for VANETs.

PHY/MAC Uplink Performance of LoRa Class A Networks

Recently, low-power wide-area networks (LPWANs) have attracted great interest due to the need of connecting more and more devices to the so-called Internet of Things (IoT). LoRa networks are LPWANs that allow a long-range radio connection of multiple devices operating in nonlicensed bands. In this article, we characterize the performance of LoRa’s uplink communications where both physical layer (PHY) and medium access control (MAC) are taken into account. Motivated by recent works that consider the possibility of decoding multiple frames at the same time, we characterize the performance of the PHY layer through the probability of decoding multiple frames that were transmitted with the same spreading factor. The MAC performance is evaluated by considering that the interarrival time of the frames generated by each LoRa device is exponentially distributed. A LoRaWAN operating scenario is considered, where the transmissions of LoRa Class A devices are influenced by path loss, shadowing, and Rayleigh fading. The numerical results obtained with the modeling methodology are compared with simulation results, and the validation of the proposed model is discussed for different traffic load levels, different PHY-layer conditions, and different capture thresholds. The contribution of this article is primarily focused on studying the average number of decoded LoRa frames for the different capture conditions, being a general model when compared to the works published so far. Moreover, given the different research initiatives to develop innovative multicapture LoRa schemes, we believe that the proposed model is particularly useful to foresee LoRa’s PHY/MAC performance in such innovative scenarios.

Underwater optical wireless communication-based IoUT networks: MAC performance analysis and improvement

Underwater Optical Wireless Communication (UOWC) is a high-speed data transmission technology promising to support the concept of the Internet of Underwater Things (IoUT). The performance of UOWC-based IoUT networks, especially medium access control (MAC), could be affected significantly by physical factors in the underwater environment. However, there is a lack of studies on the MAC performance analysis and improvement in the literature. We study in this paper a PHY/MAC cross-layer analysis that theoretically investigates the effect of UOWC PHY transmission errors on the performance of Slotted ALOHA-based MAC. To improve the performance, we propose to enable frame retransmission in the operation of Slotted ALOHA, where the optimal number of retransmissions is studied. As confirmed in the numerical results, frame retransmission could considerably improve the MAC performance. Also, the Monte Carlo simulation verifies the accuracy of our theoretical derivation for the PHY/MAC cross-layer analysis.

Theoretical modeling for performance analysis of IEEE 1901 power-line communication networks in the multi-hop environment

As one of the most promising networking technologies, power-line communication (PLC) networks have been gradually used not only in home networking systems but also in industrial IoT (Internet of things). Current studies of PLC medium access control (MAC) protocol (i.e., IEEE 1901) only focus on the single-hop environment; however, in practical industrial IoT and home access communication systems, PLC networks generally utilize a multi-hop architecture. In addition, due to the difference in the MAC standard between 802 series and 1901, existing analytical models of multi-hop IEEE 802.11 wireless networks are not suitable for multi-hop IEEE 1901 PLC networks. In this paper, we propose a theoretical model for performance analysis of multi-hop IEEE 1901 PLC networks, where the impacts of traffic rate (containing relay traffic), buffer size, deferral counter process of 1901, hidden terminal problem and multi-hop environment are comprehensively considered. The modeling process is divided into two parts. In the local modeling part, we construct a brand-new Markov chain model to investigate the carrier sense multiple access with collision avoidance process of IEEE 1901 protocol under the multi-hop environment. In the coupling queueing modeling part, we employ queueing theory to analyze the packet transmission procedure between successive hops. On the basis, we derive the closed-form expressions of throughput, medium access delay, packet blocking probability, end-to-end successful transmission delay and goodput. Through extensive simulations, we verify that our theoretical model can accurately estimate the MAC performance of IEEE 1901 PLC networks in the multi-hop environment.

A PHY/MAC Cross-Layer Analysis for IEEE 802.15.7 Uplink Visible Local Area Network

Supported by IEEE 802.15.7 standardization activities, visible local area network (VLAN) has been gaining popularity in recent years. Specified in the standard are physical (PHY) and uplink medium access control (MAC) layers of VLAN. However, there is a lack of studies on the MAC performance analysis and improvement under the effects of PHY transmission errors in the literature. We thoroughly analyze the MAC for various performance metrics taking into account PHY transmission errors due to different VLC physical factors. We also consider MAC enabling frame retransmissions as a solution to PHY transmission errors. Numerical results show that, first, MAC performance is critically affected by PHY transmission errors and, second, frame retransmissions, with a proper setup, could considerably improve the performance.

A Dynamic Surface Gateway Placement Scheme for Mobile Underwater Networks.

Deployment of surface-level gateways holds potential as an effective method to alleviate high-propagation delays and high-error probability in an underwater wireless sensor network (UWSN). This promise comes from reducing distances to underwater nodes and using radio waves to forward information to a control station. In an UWSN, a dynamic energy efficient surface-level gateway deployment is required to cope with the mobility of underwater nodes while considering the remote and three-dimensional nature of marine space. In general, deployment problems are usually modeled as an optimization problem to satisfy multiple constraints given a set of parameters. One previously published static deployment optimization framework makes assumptions about network workload, routing, medium access control performance, and node mobility. However, in real underwater environments, all these parameters are dynamic. Therefore, the accuracy of performance estimates calculated through static UWSN deployment optimization framework tends to be limited by nature. This paper presents the Prediction-Assisted Dynamic Surface Gateway Placement (PADP) algorithm to maximize the coverage and minimize the average end-to-end delay of a mobile underwater sensor network over a specified period. PADP implements the Interacting Multiple Model (IMM) tracking scheme to predict the positions of sensor nodes. The deployment is determined based on both current and predicted positions of sensor nodes, which enables better coverage and shorter end-to-end delay. PADP uses a branch-and-cut approach to solve the optimization problem efficiently, and employs a disjoint-set data structure to ensure connectivity. Simulation results illustrate that PADP significantly outperforms a static gateway deployment scheme.

Enhancing MAC performance of DCF protocol for IEEE 802.11 wireless LANs

Abstract The DCF (Distributed Coordination Function) is the basic MAC (Medium Access Control) protocol of IEEE 802.11 wireless LANs and compatible with various IEEE 802.11 PHY extensions. The performance of the DCF degrades exponentially as the number of nodes participating in the DCF transmission procedure increases. To deal with this problem, we propose a simple, however efficient modification of the DCF by which the performance of the DCF is greatly enhanced.

IEEE 802.11 무선랜의 성능 향상을 위한 하이브리드 MAC 프로토콜

The DCF (Dcistributed Coordination Function) and PCF (Point Coordination Function) are the basic MAC (Medium Access Control) protocols of IEEE 802.11 wireless LANs. According to the DCF, each node performs the exponential backoff algorithm before the transmission of its data frame. Each node doubles the backoff waiting time before the transmission of its data frame whenever it detects the transmission collision with other nodes. Therefore, as the number of the active nodes having the data frames to transmit increases, the overall MAC performance of the DCF decreases. On the other hand, according to the PCF, each node is granted the transmission opportunity by which the PCF transmission is possible without the collision with other nodes. Therefore, as the number of the active nodes increases, the MAC performance of the PCF increases, In this paper, considering the tradeoff of MAC performance between the DCF and PCF, a hybrid MAC protocol is proposed to enhance the performance of IEEE 802.11 wireless LANs. †

Modeling IEEE 802.15.4 Networks Over Fading Channels

Although the performance of the medium access control (MAC) of the IEEE 802.15.4 has been investigated under the assumption of ideal wireless channel, the understanding of the cross-layer dynamics between MAC and physical layer is an open problem when the wireless channel exhibits path loss, multi-path fading, and shadowing. The analysis of MAC and wireless channel interaction is essential for consistent performance prediction, correct design and optimization of the protocols. In this paper, a novel approach to analytical modeling of these interactions is proposed. The analysis considers simultaneously a composite channel fading, interference generated by multiple terminals, the effects induced by hidden terminals, and the MAC reduced carrier sensing capabilities. Depending on the MAC parameters and physical layer thresholds, it is shown that the MAC performance indicators over fading channels can be far from those derived under ideal channel assumptions. As novel results, we show to what extent the presence of fading may be beneficial for the overall network performance by reducing the multiple access interference, and how this information can be used for joint selection of MAC and physical layer parameters.

Optimizing Spatial and Temporal Reuse in Wireless Networks by Decentralized Partially Observable Markov Decision Processes

The performance of medium access control (MAC) depends on both spatial locations and traffic patterns of wireless agents. In contrast to conventional MAC policies, we propose a MAC solution that adapts to the prevailing spatial and temporal opportunities. The proposed solution is based on a decentralized partially observable Markov decision process (DEC-POMDP), which is able to handle wireless network dynamics described by a Markov model. A DEC-POMDP takes both sensor noise and partial observations into account, and yields MAC policies that are optimal for the network dynamics model. The DEC-POMDP MAC policies can be optimized for a freely chosen goal, such as maximal throughput or minimal latency, with the same algorithm. We make approximate optimization efficient by exploiting problem structure: the policies are optimized by a factored DEC-POMDP method, yielding highly compact state machine representations for MAC policies. Experiments show that our approach yields higher throughput and lower latency than CSMA/CA based comparison methods adapted to the current wireless network configuration.

A CART Based Mechanism for Collision Detection in IEEE 802.11

The ability to detect and distinguish packet errors due to collisions from those caused by channel errors can significantly impact the performance of medium access control (MAC) protocols such as IEEE 802.11. In particular, such mechanisms affect the backoff mechanism as well as rate adaptation algorithms. This paper presents a real-time algorithm based on classification and regression trees (CART) for distinguishing packet corruption and losses due to channel errors from those caused by collisions with other simultaneous transmissions. Using a set of four metrics, we propose a classifier tree that reduces the classification errors by considering the impact of channel variations and collisions on bit errors from multiple, disparate perspectives. Extensive simulation results are used to verify the superior performance of the proposed technique over existing mechanisms.

Modeling and stability analysis of hybrid multiple access in the IEEE 802.15.4 protocol

To offer flexible quality of service to several classes of applications, the medium access control (MAC) protocol of IEEE 802.15.4 wireless sensor networks (WSNs) combines the advantages of a random access with contention with a time division multiple access (TDMA) without contention. Understanding reliability, delay, and throughput is essential to characterizing the fundamental limitations of the MAC and optimizing its parameters. Nevertheless, there is not yet a clear investigation of the achievable performance of hybrid MAC. In this article, an analytical framework for modeling the behavior of the hybrid MAC protocol of the IEEE 802.15.4 standard is proposed. The main challenge for an accurate analysis is the coexistence of the stochastic behavior of the random access and the deterministic behavior of the TDMA scheme. The analysis is done in three steps. First, the contention access scheme of the IEEE 802.15.4 exponential back-off process is modeled through an extended Markov chain that takes into account channel, retry limits, acknowledgements, unsaturated traffic, and superframe period. Second, the behavior of the TDMA access scheme is modeled by another Markov chain. Finally, the two chains are coupled to obtain a complete model of the hybrid MAC. By using this model, the network performance in terms of reliability, average packet delay, average queuing delay, and throughput is evaluated through both theoretical analysis and experiments. The protocol has been implemented and evaluated on a testbed with off-the-shelf wireless sensor devices to demonstrate the utility of the analysis in a practical setup. It is established that the probability density function of the number of received packets per superframe follows a Poisson distribution. It is determined under which conditions the guaranteed time slot allocation mechanism of IEEE 802.15.4 is stable. It is shown that the mutual effect between throughput of the random access and the TDMA scheme for a fixed superframe length is critical to maximizing the overall throughput of the hybrid MAC. In high traffic load, the throughput of the random access mechanism dominates over TDMA due to the constrained use of TDMA in the standard. Furthermore, it is shown that the effect of imperfect channels and carrier sensing on system performance heavily depends on the traffic load and limited range of the protocol parameters. Finally, it is argued that the traffic generation model established in this article may be used to design an activation timer mechanism in a modified version of the CSMA/CA algorithm that guarantees a stable network performance.

Performance of a Concurrent Link SDMA MAC Under Practical PHY Operating Conditions

Space division multiple access (SDMA)-based medium access control (MAC) protocols have been proposed to enable concurrent communications and improve link throughput in multi-input-multi-output (MIMO) ad hoc networks. For the most part, the works appearing in the literature make idealized and simplifying assumptions about the underlying physical layer and some aspects of the link adaptation protocol. The result is that the performance predicted by such works may not necessarily be a good predictor of the actual performance in a fully deployed system. In this paper, we look to introduce elements into the SDMA-MAC concept that would allow us to better predict their performance under realistic operating conditions. Using a generic SDMA MAC, we look at how the network sum throughput changes with the introduction of the following: (1) use of the more practical MMSE algorithm, instead of the zero-forcing or singular-value-decomposition-based nulling algorithms used for receive beamnulling; (2) impact of channel estimation errors; (3) introduction of link adaptation mechanism specifically designed for concurrent SDMA MACs; and (4) incorporation of TX beamforming along with RX beamnulling. Following on the transmission window during which concurrent transmissions are allowed by the MAC, we qualify the impact of each of these four elements in isolation. At the conclusion, the performance of a system that incorporates elements 1-4 is presented and compared against the baseline system, showing an improvement of up to five times in the overall network sum throughput.