Hybrid Medium Access Control Protocol Research Articles

Adaptive Data Transmission Protocols for Energy Harvesting WSNs Used in Agriculture

Energy consumption is a major concern in wireless sensor networks (WSNs) as it affects the lifespan of sensor nodes. Battery-based WSNs have a short operating period, which makes them impractical for real-time applications, for instance in agriculture. Energy harvesting and suitable medium access control (MAC) protocols have been used to extend the lifetime of nodes. Receiver-initiated protocols have been proved to be the best solution for energy harvesting WSNs. However, they suffer from a key disadvantage, i.e. an increase in collision rate. These collisions need to be reduced using a multi-layer protocol structure. In such a context, a new solar-based hybrid MAC (SHMAC) protocol relying on receiver-initiation and characterized by a multi-layer structure is proposed. It is an adaptive protocol capable of adapting to changing weather conditions. The nodes with a high energy harvesting rate have a higher level of residual energy and are active for longer time periods compared with those with low energy harvesting characteristics. The proposed work has shown improvements in two major MAC layer parameters, i.e. collision rate and energy neutrality operation ratio (ENO).

A cross-layer approach for load balancing and energy-efficient QoS-based routing reliability for UWSN

Considering several fundamental needs of network performance, the Routing and Media Access Control (MAC) layers are crucially checked out for their operations. Sometimes, MAC protocol faces difficulties in modifying the situations over underwater communication which are specifically considered to be dynamic. The nodes in water tend to remain unstable and network fluctuations are made depending upon the number of competitors. The existing hybrid MAC protocol does not possess dynamic network loads. It also involves a lack of modification in access control approaches which provide variations in network loads. Finally, it leads to delayed network performance. The routing layer focus on some difficult parameters like increased packet loss, restricted bandwidth with substantial energy incursion, reduced network lifetime, increased propagation delay, less remaining energy, consistent data transfer, and energy organization which are considered to be the most important research issues in Underwater Acoustic Sensor Networks (UWASNs). In MAC and routing layers, a Cross-layer approach involves some techniques which are discussed and implemented using Ns3 simulation to obtain the performance report. It is also proposed to compare the algorithm with existing techniques to provide accurate results. Reinforcement Learning (RL) in the MAC layer for SINR-based time slot allocation and Integrated Artificial Fish Swarm with Bacterial Foraging Algorithm (IAFSBFA) for energy-aware QoS reliable routing in the network layer are used in this system. In this cross-layer approach, load balancing in the MAC layer and efficient routing using a hybrid algorithm gives out better performance in the underwater network.

RE-MAC: A Hybrid MAC Protocol for Underwater Multimedia Communication System

In this article, we propose a reliable and efficient medium access control (MAC) protocol, RE-MAC, for resource-constraint underwater acoustic multimedia communication systems. RE-MAC achieves scalability by utilizing a hybrid MAC protocol smartly, which takes advantage of contention, reservation, and null data packet (NDP) based channel access mechanisms. The proposed scheme achieves multihop communication and synchronization for video streaming using a transmission opportunity (TXOP) based efficient channel access mechanism at the access point (AP) and relay nodes. TXOP time has been utilized by relay and AP for sending stream of frames with low overhead. To improve the efficiency in multihop communication, RE-MAC finds an optimal frame duration for relays and AP. RE-MAC efficiently places the NDP mechanism replacing traditional ACK-based control packet exchange. We incorporate the TXOP in AP and relay nodes for multimedia streaming and sleep mode for stations. Further, the video compression technique gives the efficiency of our system to improve the transmission of multimedia data. Our proposed schemes help communicate multimedia data without compromising the quality of service. We have demonstrated our proposed scheme experimentally in a prototype. After that, a simulation-based detailed performance analysis is provided to see the scalability of the proposed scheme. Compared to the existing state-of-the-art solutions, RE-MAC significantly delivers the throughput, energy consumption, delay, and packet loss.

An analytical model for the directional hybrid MAC protocol in the IEEE 802.15.3c

Nowadays, mobile data demand has grown significantly. Millimeter-wave (mm-wave) bands are a favorable technology to support high data rate communication. The IEEE 802.15.3c standard is an attractive candidate for mm-wave carrier frequencies for short-range indoor applications. Providing a comprehensive analytical model of the medium access control (MAC) layer gives great information to improve network performance. In this paper, for the first time, a comprehensive Markov chain model has been presented for the IEEE 802.15.3c standard by considering the directional antenna , hybrid MAC and queue. The exact queue models ( M / G /1 and M / D /1 queue) have been considered for the Regular Contention Access Period (RCAP) and Channel Time Allocation Period (CTAP) areas. The number of beam sectors and path loss model for the directional antenna is considered in the presented model. The most essential analytical parameters including throughput, delay, reliability, queue size, and system instability of each RCAP and CTAP area for the different number of sectors, RCAP area length, nodes, traffic and room size, have been investigated. Maximum throughput has been determined for the optimum value of these parameters. OPNET simulation validates our represented analytical model and shows that it is more accurate than other states of the art articles.

Priority-Based Hybrid MAC Protocol for VANET with UAV-Enabled Roadside Units

Vehicular ad hoc networks (VANETs) connect vehicles with other network units through wireless communication, thus improving traffic efficiency and safety by interacting with traffic information in networks. Roadside unit (RSU) plays an important role in VANETs in connecting vehicles with the transportation centre. With the rapid development of unmanned aerial vehicles (UAV), UAV-enabled RSU (U-RSU) is an effective way to promote the performance of VANETs. In this paper, a novel medium access control (MAC) layer protocol named PHB-MAC is proposed based on the priority setting of transmitted messages. Firstly, the priority-based contention mechanism is presented to ensure the transmission efficiency of the safety message. Then, the proposed MAC protocol combining contention and adaptive scheduled scheme is described in detail. Finally, the numerical analysis and simulation results of PHB-MAC and other existing protocols are presented. It is revealed that the proposed protocol improves throughput by at least 30%. Meanwhile, it reduces packets drop rate and delay by 21% and 22%, respectively. Finally, the numerical analysis and simulation results are given to prove the advancement of the proposed protocol on throughput, packets drop rate (PDR), and delay.

Novel approach for hybrid MAC scheme for balanced energy and transmission in sensor devices

<p><span>Hybrid medium access control (MAC) scheme is one of the prominent mechanisms to offer energy efficiency in wireless sensor network where the potential features for both contention-based and schedule-based approaches are mechanized. However, the review of existing hybrid MAC scheme shows many loopholes where mainly it is observed that there is too much inclusion of time-slotting or else there is an inclusion of sophisticated mechanism not meant for offering flexibility to sensor node towards extending its services for upcoming applications of it. Therefore, this manuscript introduces a novel hybrid MAC scheme which is meant for offering cost effective and simplified scheduling operation in order to balance the performance of energy efficiency along with data aggregation performance. The simulated outcome of the study shows that proposed system offers better energy consumption, better throughput, reduced memory consumption, and faster processing in contrast to existing hybrid MAC protocols.</span></p>

Elastic hybrid MAC protocol for wireless sensor networks

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

An intelligent hybrid MAC protocol for a sensor-based personalized healthcare system

Sensors based on personalized healthcare systems have been widely used in the medical field. However, energy limitations have greatly hindered the further development of medical sensors. For the traditional Medium Access Control (MAC) protocol, the duration of low-power listening is fixed because it ignores that the available energy of sensors is different in some situations, which leads to a high delay and low energy utilization. In this paper, a Maximum Listening Length MAC (MLL-MAC) protocol is proposed to fully utilize the energy in the sensor-based systems. The MLL-MAC protocol is an improvement of the Receiver-Initiated (RI) MAC protocol. The main advance is that the sensor node performs the following additional operations: (1) The sender sends a beacon when it wakes up and sends data, thus establishing a communication link with the receiver in the listening state; (2) The receiver keeps listening as long as possible to reduce the delay when it wakes up and listens to the channel, which is different from the previous strategy in which the node turns into a sleep state immediately without receiving data. Furthermore, the sensor node can dynamically determine whether to send beacons and prolong listening duration according to its available energy level. The MLL-MAC protocol is evaluated through theoretical analysis and experimental results. The results show that, compared with the RI-MAC protocol, the MLL-MAC protocol can reduce the average end-to-end delay by 41.4% and improve the energy utilization by 15.1%.

An energy efficient hybrid MAC protocol for smart home networks

In this paper cluster-based hybrid MAC (CB-HMAC) protocol, based on IEEE 802.15.4 MAC is proposed for smart home networks. The CB-HMAC is specially designed for short packet transmission in a dense home network environment. Simulation results show that the proposed CB-HMAC is more energy-efficient than other medium access control (MAC) protocols without sacrificing much delay and throughput.

Hybrid Medium Access Control Protocol for Radio-Over-Fiber Networks

The oncoming Internet-of-things (IoT) applications and smart machine-to-machine (M2M) communication lead to an enormous increase in network traffic. To meet the escalating demands of these time-critical applications, we need a hybrid optical-wireless network, for which the radio-over-fiber (RoF) technology is a promising candidate. These networks need to support the stringent delay requirements of the above applications for a large number of mobile users. However, the existing user registration and identification approaches for these networks are not efficient for a high user density and cannot keep the overall mean delay within the permissible limit for such applications. In this article, we present a hybrid medium access control (MAC) protocol for the RoF network, for which we propose hybrid user identification and neighbor-aware hybrid user identification algorithms for high user density. Further, the MAC protocol uses a gated polling method for data transfer. Moreover, we propose an analytical delay model for the hybrid MAC protocol, which gives overall end-to-end mean delay considering user identification and data transfer. We verify it with the results obtained from the simulations. Finally, we evaluate the mean delay and packet loss rate of the proposed algorithms by varying the network load, user density, and fiber length and benchmark the performance of the proposed algorithm with the state-of-the-art (SoA).

CFFD-MAC: A Hybrid MAC for Collision Free Full-Duplex Communication in Wireless Ad-Hoc Networks

Infrastructure-less (sometimes known as ad-hoc) networking paradigm is very appealing and potentially shaping its future into almost all emerging networks (i.e., IoT, wireless sensor networks, vehicular ad-hoc networks, emergency, and tactical radio networks, etc.). However, when conventional networking protocols are used, such networks often perform poorly, mainly because of interference within the network and limited network throughput. Recent advancements in wireless communications have enabled full-duplex (FD) operation by suppressing self-interference, which can theoretically double the network throughput. However, conventional medium access control (MAC) protocols like carrier-sense multiple access with collision avoidance (CSMA/CA) favor half-duplex (HD) operation and fail to benefit from FD transmission opportunities. This article proposes a novel hybrid MAC protocol for full-duplex ad-hoc networks. The proposed MAC combines time division multiple access (TDMA) and IEEE 802.11 distributed coordination function (DCF) strengths in chains of time-slotted contention-based control frames and collision-free data frames. The aim is to fully utilize FD transmission opportunities to increase network throughput. The proposed protocol modifies request-to-send (RTS) and clear-to-send (CTS) frames in IEEE 802.11 DCF MAC to form FD-RTS/CTS frames. These frames are used to enable collision-free FD communications among neighbors. The proposed scheme mitigates conventional MAC issues like hidden-node problem (HNP) and exposed-node problem (ENP). It also allows concurrent FD data transmissions in a collision-free manner. The model is generic and can be applied to any ad-hoc wireless network. In this article, the design is applied to a single channel ad-hoc network with FD transceivers. We compared the proposed design with IEEE 802.11 CSMA/CA protocol with both HD and FD transceivers. The simulation results show a 30% gain in throughput, reduced latency, and fairness among participating wireless nodes.

Hybrid MAC Protocol for Brain–Computer Interface Applications

Brain-computer interface (BCI) can permit individuals to use their thoughts as the sole means to control objects such as smart homes and robots. While BCI is a promising interdisciplinary tool, researchers are confronting network lifetime as an obstacle to further development. Furthermore, the medium access control (MAC) protocol is the bottleneck of the network reliability. There are many standards for MAC protocols that can be utilized for productive and dependable transmission by altering the control parameters. Modifying these parameters is another source of concern due to the scarcity in knowledge about its effect. In addition, there is no instrument accessible to receive and actualize these parameters on transmitters embedded inside the cerebrum. In this article, we give the transmission instrument to both ultrahigh-frequency (UHF) radio frequency identification (RFID) and ultra-wideband (UWB) signals for multiple transmitters and ultrasonic technology mimicking the neural dusts by modifying the superframe structure. In this article, a hybrid MAC protocol is proposed, and the results show that the traffic received can be increased by 700% for UHF-RFID and more than 100% for UWB and ultrasonic technology. Comparative results for wireless channel MAC protocols using these different transmission techniques are discussed in terms of network delay, data dropped, traffic sent, and traffic received.

Energy-efficient hybrid MAC protocol for railway monitoring sensor network

In the present work, a new protocol is proposed i.e. application-specific hybrid medium access control (ASHMAC) to efficiently handle data traffic generation in the railway track condition monitoring system. ASHMAC protocol is an improved version of the bit-map-assisted (BMA) medium access control (MAC) protocol by which it can efficiently handle continuous monitoring data traffic as well. Simulation and mathematical models have been developed and proposed for ASHMAC protocol. Its performance is compared with the other MAC protocols. The results reveal that the proposed protocol consumes 25–50% less energy w.r.t. time division multiple access (TDMA), energy-efficient TDMA, and BMA at low to medium data traffic conditions. For high data traffic conditions, the energy consumption of the proposed ASHMAC protocol is approximately equal to the other protocols. The transmission latency of ASHMAC is approximately 50% less than energy-efficient BMA. Both analytical and simulation results show the overall superiority of the proposed protocol.

A Collision-Free Hybrid MAC Protocol Based on Pipeline Parallel Transmission for Distributed Multi-Channel Underwater Acoustic Networks

The transmission rate between two nodes is usually very low in underwater acoustic networks due to the low available bandwidth of underwater acoustic channels. Therefore, increasing the transmission parallelism among network nodes is one of the most effective ways to improve the performance of underwater acoustic networks. In this paper, we propose a new collision-free hybrid medium access control (MAC) protocol for distributed multi-channel underwater acoustic networks. In the proposed protocol, handshaking and data transmission are implemented as a pipeline on multiple acoustic channels. Handshaking is implemented using the time division multiple access (TDMA) technique in a dedicated control channel, which can support multiple successful handshakes in a transmission cycle and avoid collision in the cost of additional delay. Data packets are transmitted in one or multiple data channels, where an algorithm for optimizing the transmission schedule according to the inter-nodal propagation delays is proposed to achieve collision-free parallel data transmission. Replication computation technique, which is usually used in parallel computation to reduce the requirement of communication or execution time, is used in the data packet scheduling to reduce communication overhead in distributed environments. Simulation results show that the proposed protocol outperforms the slotted floor acquisition multiple access (SFAMA), reverse opportunistic packet appending (ROPA), and distributed scheduling based concurrent transmission (DSCT) protocols in throughput, packet delivery rate, and average energy consumption in the price of larger end-to-end delay introduced by TDMA based handshaking.

Energy Efficient Mobility Aware Clustering Hybrid MAC Protocol in WSN

Mobility in Wireless Sensor Networks (WSN) poses many challenges to design Medium Access Control (MAC) protocol. In this paper, Energy efficient clustering Mobility Hybrid MAC (EMH-MAC) protocol is introduces to manage throughput, delay and energy consumption in WSN. EMH-MAC protocol merges the features of synchronous and asynchronous MAC protocols. EMH-MAC works in two stages: Clustering and Data transmission stage. In the clustering stage MMCDD protocol is used for election of Cluster Head (CH). Data transmission stage works in four segments: two-hop neighbor information, intra-semi synchronous, inter-synchronous communication and data transfer. EMH-MAC is evaluated using Network Simulator-3 and performance is compared with BN-MAC. Simulation results show that EMH-MAC performs well in comparison with BN-MAC in terms of throughput, delay and energy consumption by varying number of nodes and speed of nodes.

On Research Challenges in Hybrid Medium-Access Control Protocols for IEEE 802.15.6 WBANs

IEEE 802.15.6 is a wireless body area network (WBAN) standard proposed to facilitate the exponentially growing interest in the field of health monitoring. This standard is flexible and outlines multiple basic medium-access control (MAC) protocols that are contention based and collision free to meet the WBAN quality-of-service (QoS) challenges. Typically, current research trends in WBAN MAC focus on designing a hybrid MAC that is a combination of basic MAC protocols. In this paper, we provide a first detailed survey of existing hybrid MAC protocols based on the IEEE 802.15.6, which would be useful for the related research community. First, this paper lists the design challenges of a WBAN MAC. Second, it highlights the significance of hybrid MAC protocols in meeting the design challenges while comparing them to standard MAC protocols. Third, a critical and thorough comparison of existing hybrid MAC protocols is presented in terms of network QoS and WBAN specific parameters. Finally, we identify key open research areas that are often neglected in hybrid MAC design and further propose some possible directions for future research.

A Novel Hybrid MAC Protocol for Basic Safety Message Broadcasting in Vehicular Networks

Basic Safety Messaging plays a crucial role to provide road safety in vehicular ad-hoc networks (VANETs). To avoid potential accidents, vehicles periodically broadcast safety information to neighboring vehicles. However, due to transmission collisions, fading channels and other factors, vehicular networks usually suffer a low packet delivery ratio (PDR) and a large delay, which are intolerant of many safety applications. To tackle these issues, this paper proposes a hybrid medium access control (MAC) protocol for basic safety message (BSM) dissemination based on the framework of Dedicated Short-Range Communication (DSRC). Its partially centralized and partially distributed characteristic not only can effectively suppress the collisions, but keep compatibility with IEEE 802.11p. In addition, the integration of Physical-Layer Network Coding (PNC) and Random Linear Network Coding (RLNC) further strengthens the reliability and efficiency for BSM dissemination. Both the theoretical analysis and comprehensive simulations indicate that, compared with existing schemes, the proposed protocol can significantly improve the PDR by a range of 20% to 300%. Meanwhile, in terms of normalized throughput, it increases by varying percent between 20% and 160% in different scenarios.

An Energy Efficient Hybrid MAC Protocol With Dynamic Sleep-Based Scheduling for High Density IoT Networks

Advances in the development of low powered sensors has meant they can now provide solutions to Internet of Things (IoT) networks that suffer from restricted power supply and a lack of resource facilities. In this paper, a hybrid time division multiple access (TDMA)-carrier sense multiple access with a collision avoidance mechanism (CSMA/CA) medium access control (MAC) protocol has been proposed that efficiently utilizes the energy of the nodes and dynamically adapts the sleep/wake-up periods according to the variance in the network loads. This hybrid protocol first schedules the TDMA time slots (TDMA <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">slots</sub> ), and then allocates each slot to a group of devices that compete for the medium using the CSMA/CA. This case is different from the traditional CSMA/CA-TDMA hybrid protocol, in which all the devices compete to access the channel, following which, each successful device is allocated an individual time slot. At the commencement of each superframe, the base station broadcasts a scheduler table, which includes network grouping information that is used by the IoT devices to categorize themselves into wake-up and sleep groups. To reduce the number of collisions or channel access failures, this information permits only one group to compete for each TDMA <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">slot</sub> . A 3-D Markov model is used to develop a per user stochastic behavior for the proposed hybrid MAC protocol-based adaptable sleep mode. The simulation results demonstrate the effectiveness of the proposed protocol, which improves the network throughput and enhances energy conservation by 40%-60% more than the IEEE 802.15.4-based MAC protocol.

A Load-Based Hybrid MAC Protocol for Underwater Wireless Sensor Networks

In underwater wireless sensor networks (UWSNs), media access control (MAC) is important because it may have a significant impact on network performance; however, the complex and changeable underwater communication environment is a great challenge for the MAC protocol. In flowing water, the network nodes are constantly moving, and the number of competitors in the network also varies. The existing hybrid MAC protocol neither can adapt to the dynamic network load nor can switch the access control protocols with changing network loads, which may result in poor network performance. In order to solve the above problems, this paper proposes a load-based time slot allocation (LBTSA) protocol. The LBTSA selects the slot allocation scheme, from a set of possible schemes, according to the instantaneous network load. Then, based on the relative priority of the nodes and the optimal number of backoff stages, the host node selects the optimal access control protocol. This not only adapts well to changing network loads but also maximizes network throughput. By assuming that the number of competitors obeys a universal Poisson distribution, the LBSTA protocol and the HCR (a hybrid MAC protocol using channel reservation) protocol are compared. As the results show, the throughput of the LBTSA is higher than that of the HCR protocol, and the end-to-end delay of the LBTSA is lower than that of the HCR protocol.

Optimised approach based on hybrid MAC protocol for M2M networks

In machine-to-machine (M2M) networks, the ability to access the radio channel requires a rigid design of a medium access control (MAC) protocol. Here, an optimised hybrid MAC protocol will be proposed which is composed of two main processes, the contending process and the transmission process. During contention process, the devices randomly contend the transmission opportunities with equal probabilities by using the conventional-based slotted ALOHA (S-ALOHA) mechanism. Only successful devices can assign a transmission slot during the transmission process by using the reservation-based time division multiple access mechanism. Additionally, an optimisation problem will be formulated to obtain the maximum aggregated throughput. Moreover, the optimum relation between the contention and transmission periods under different number of devices is calculated. The optimisation problem is solved with the aid of mathematical analysis which is carried out through Monte Carlo simulation. Furthermore, extensive MATLAB programs are executed to study the system performance in terms of: the system throughput, the average packet delay, the success access ratio, and the reservation ratio. The simulation results show that the proposed hybrid technique outperforms other related hybrid when compared.