Medium Access Control Scheme Research Articles

AWG-based WDM ring networks: High-performance and low-cost system designs

Optical packet switching (OPS) ring networks are regarded as being promising solutions for future optical metropolitan area networks. In this paper, we propose novel arrayed-waveguide grating (AWG)-based wavelength division multiplexing (WDM) ring network systems that are aimed at achieving low-cost, scalable, and high-performance systems. By exploiting the cyclic routing properties and spatial wavelength reuse of a passive 2*2 AWG device, we redesign the ring network into a two-subring network, connected through the AWG device. The network is governed by a novel distributed medium access control (MAC) scheme, and we further derive a highly efficient and fair bandwidth allocation in accordance with a quota. A previously proposed experimental optical packet-switched WDM metro-ring network, called HOPSMAN, has shown to have exceptional performance among the OPS ring network studies. We show simulation and analytic results to demonstrate that our proposed system have achieved enhanced performance of the TT (tunable transmitter)-TR (tunable receiver)-based HOPSMAN by 1.5 times but have used only low-cost TT-FR (fixed-tuned receiver) or FT (fixed-tuned transmitter)-FR optical devices. Thus, the proposed networks achieve exceptional network throughput and also greatly reduce system costs.

LDMAC: A propagation delay-aware MAC scheme for long-distance UAV networks

Unmanned aerial vehicles (UAVs) are gaining increasing importance in military and civilian applications. A challenging problem is the efficient communication between multiple UAVs and terrestrial base station (BS), where a wireless link has to cover hundreds of miles. These long-distance wireless networks suffer from heterogeneous and varying propagation delays, making conventional medium access control (MAC) protocols inappropriate. In this paper, a propagation delay-aware access scheme, LDMAC, is designed for long-distance UAV networks. It is a joint design of random access and collision-free time slot allocation. UAVs contend for time slots based on improved Irregular Repetition Slotted Aloha (IRSA), and subsequently the BS makes a collision-free, fair and optimized time slot allocation with temporal reuse. Both of the processes take full advantage of propagation delay to efficiently improve system throughput. Simulation results show that LDMAC achieves up to 30% improvement over IRSA with respect to successful decoding rate (SDR), and outperforms competing protocols that include IRSA and dynamic time division multiple access (D-TDMA) in terms of throughput in mobile wireless networks.

Optimizing Performance Parameters in Wireless Sensor Network using Hybrid Medium Access Control

To carry out an efficient data aggregation operation, it is essential to retain the optimal number of nodes for an extensive sensing period in wireless sensor networks. Hybrid Medium Access Control (MAC) uses its contention and scheduling options to offer this feature by facilitating access over the shared resources and offering better energy efficiency. However, a review of existing approaches highlights that there is still a large scope for improvement. Therefore, the proposed system introduces a model forhybrid MAC that facilitates optimal routine management of states of nodes and offers a dual optimization model by ensuring extensive participation of intermediate nodes. The proposed scheme Simulated in MATLAB, the study outcome shows that it offers a good balance between energy efficiency and communication performance in comparison to existing hybrid MAC schemes.

Reliable and enhanced cooperative cross‐layer medium access control scheme for vehicular communication

In an unreliable cluster-based, broadcast vehicular network setting, the authors investigate the transmission reliability and throughput performance of random network coding (RNC) as a function of the percentage of packet generation rate and transmit power-to-noise ratio. In this study, a novel scheme called reliable and efficient cooperative cross-layer medium access control (RECMAC) is proposed. The proposed scheme consists of a source vehicle broadcasting packets to a set of receivers (i.e. one-to-many) over independent broadcast erasure channels. The source vehicle performs RNC on N packets and broadcasts the encoded message to a set of receivers. In each hop, several vehicles form a cluster and cooperatively transmit the encoded or re-encoded packet. The combination of the RNC, cluster based, and cooperative communications enables RECMAC to optimally minimise data redundancy, which means less overhead, and improve reliability as opposed to coding-based solutions. Theoretical analyses and simulation results show that under the same conditions RECMAC scheme can achieve improved performance in terms of transmission reliability and throughput.

Energy‐efficient medium access control and routing protocol for multihop wireless sensor networks

This work presents a combined energy-efficient medium access control (MAC) and routing protocol for large-scale wireless sensor networks that aims to minimise energy consumption and prolong the network lifetime. The proposed communication framework employs the following measures to enhance the network energy efficiency. Firstly, it provides an adaptive intra-cluster schedule to arbitrate media access of sensor nodes within a cluster, minimising idle listening on sensor nodes, leading to improved energy performance. Secondly, it proposes an on-demand source cross-layer routing protocol ensuring selection of best routes based on energy level and channel quality indicator for the multihop inter-cluster data transmission. Lastly, an unequal cluster size technique based on cluster head residual energy and distance away from the base station is utilised. This technique balances the energy among clusters and avoids early network partitioning. This work further presents the analytical performance model for energy consumption and delay of the proposed communication framework. The performance measures used for evaluation are energy consumption, delay, and network lifetime. The results indicate that combining routing and MAC schemes conserves energy better than utilising MAC scheme alone.

Maximization of multicast periodic traffic throughput in multi-hop wireless networks with broadcast transmissions

Although a number of different medium access control (MAC) schemes are adopted for wireless multi-hop networks, time division multiple access (TDMA) approaches based on a periodic frame of time slots are the most common when very high efficiency is needed in terms of use of radio and energy resources. Efficient resource usage is typically based on parallel compatible transmissions from multiple nodes that guarantee interference control at the receivers. Optimization of transmission scheduling in multi-hop packet delivery from sources to destinations for a set of traffic relations can be achieved by minimizing the frame length where all necessary transmissions are organized in compatible sets and assigned to the time slots of the frame. When properly designed, the resulting TDMA scheme guarantees the delivery of packets for each traffic relation at a rate of up to one packet per frame duration regardless of the number of the packet transmissions (hops) necessary from source to destination, and thus it is particularly suitable for periodic traffic.While similar traffic maximization problems have been studied quite extensively for the case of unicast traffic, its multicast generalization (where each packet should be delivered from the source node to possibly multiple destination nodes) has not been elaborated so far. In this paper we present such a (non-trivial) generalization, namely a mathematical programming model based on the extension of the compatible set concept where the signal-to-noise and interference (SINR) ratio is guaranteed above a threshold at multiple receivers. We first propose an algorithm for solving the problem that generates compatible sets and schedules the frame by splitting the (predefined) multicast routing trees into one-hop transmissions. The high computational efficiency of the algorithm is proven through numerical results on large networks. Next, we enrich the model by adding multicast tree optimization, illustrating its efficiency numerically as well. Finally, we present possible extensions that consider packets of different lengths (requiring multiple slots for transmission), multiple modulation and coding schemes (MCS) requiring different SINR thresholds at the receivers, and packet delay minimization.

Protocol Sequences With Carrier Sensing for Wireless Sensor Networks

Protocol sequences are deterministic binary sequences of a common period, which enjoy some special Hamming cross-correlation property by design. In contrast to random or contention-based medium access control schemes, a protocol sequence-based scheme can serve to provide at least a certain number of contention-free packet transmissions within a bounded delay for each asynchronous user in a feedback-free multiple access system. However, all protocol sequence-based schemes in the literature require that all sequence entries are mapped to slots with the same time duration, which produces a relatively low channel utilization. To overcome this inefficiency that is undesirable in delay-constrained wireless sensor networks, building on the idea of combining sequence-based access and carrier sensing, this paper proposes a new protocol sequence-based scheme, called the PS-CS. We derive the theoretical average throughput, average access delay, worst-case delay, and average energy consumption of the PS-CS. It is shown that the PS-CS produces average throughput close to the optimal capacity of ${p}$ -persistent carrier sense multiple access (CSMA), and enjoys smaller access delay than the optimal ${p}$ -persistent CSMA. In addition, we study the energy-delay tradeoff, impact of carrier sensing fault and channel error, and how to modify the PS-CS to support real-time downlink for feedback control.

A Smart Sensor Data Transmission Technique for Logistics and Intelligent Transportation Systems

When it comes to Internet of Things systems that include both a logistics system and an intelligent transportation system, a smart sensor is one of the key elements to collect useful information whenever and wherever necessary. This study proposes the Smart Sensor Node Group Management Medium Access Control Scheme designed to group smart sensor devices and collect data from them efficiently. The proposed scheme performs grouping of portable sensor devices connected to a system depending on the distance from the sink node and transmits data by setting different buffer thresholds to each group. This method reduces energy consumption of sensor devices located near the sink node and enhances the IoT system’s general energy efficiency. When a sensor device is moved and, thus, becomes unable to transmit data, it is allocated to a new group so that it can continue transmitting data to the sink node.

A survey of hybrid MAC protocols for machine-to-machine communications

Machine-to-machine (M2M) communications are envisaged to present several interesting applications in the coming years. However, they have major setbacks hurdling their massive deployment. A major challenge is ensuring the network and wireless medium robustly accommodate the millions of devices which will be part of this communication paradigm while gracefully accommodating their diverse quality of service requirements. In this regard, medium access control schemes play a vital role. Traditional contention-based protocols are constrained in their performance under high loads while scheduling-based schemes may be faced with limited scalability and poor delay guarantees. Similarly, tree-based contention resolution schemes have some finite delay associated with them. Recently, hybrids of the aforementioned schemes have been studied in literature to solve the problems associated with traditional medium access schemes. This paper surveys the state-of-the-art hybrid schemes for M2M presenting a classification of recent protocols. Furthermore, we give a summary of major areas of interest such as problem solved, approach used and trade-offs. Salient differences in the protocols are identified with insights into opportunities for improvement. Our findings reveal general design guidelines and interesting future directions.

Performance analysis of hybrid MAC scheme with multi‐slot reservation

The multi-slot reservation-based hybrid medium access control (MAC) protocol with collision prevention is analysed under a high-density deployment scenario. Extensive simulations are conducted to validate the accuracy of the proposed model (i.e. within 4% maximum relative error), which plays a theoretical guiding role in the MAC layer design and optimisation of a heterogeneous network system.

Traffic Aware Data Collection MAC Protocol for Wireless Sensor Networks

In this paper, we propose a new medium access control (MAC) protocol for wireless sensor networks for periodic data collection. The proposed MAC scheme is specifically designed for wireless sensor networks which have periodic traffic with different sampling rates. In our protocol design, sink determines the time schedule for all other nodes in the network. We discuss the design of traffic aware MAC protocol and provide a comparison with the similar MAC protocols through simulation. Under different traffic generation rate, our protocol outperforms the previous one in terms of energy consumption and packet delay. Simulation results show that our protocol demonstrates up to 35% better performance than that of most recent protocol which is proposed for this kind of application, in respect of energy consumption. Comparative analysis and simulation results show that our design considerably gives a good compromise between energy efficiency and packet latency.

MAC Protocol Operation in Energy Harvesting for 5G Networks

Two vital challenges arise in the next generation 5G networks: scarcity of spectrum and the aspect of energy efficiency (EE). In this letter, we first formulate the prime issue, i.e., energy harvesting (EV) for 5G wireless networks, in which spectrum and energy resources are efficiently received and resourcefully managed. Thereafter, we introduce a medium access control (MAC) scheme for dual tier 5G networks; it also invokes the simultaneous wireless information and power transfer (SWIPT) technique with other data transmission schemes, i.e., cooperative transmission (CT) scheme and non-cooperative transmission (NCT) scheme with EV abilities. Illustrative results demonstrate significant improvement in aggregated throughput and EE.

A Full‐Duplex MAC Tailored for 5G Wireless Networks

The increasing demands for high‐data rate traffic stimulated the development of the fifth‐generation (5G) mobile networks. The envisioned 5G network is expected to meet its challenge by devising means to further improve spectrum usage. Many alternatives to enhance spectrum usage are being researched, such as massive MIMO, operation in mmWave frequency, cognitive radio, and the employment of full‐duplex antennas. Efficient utilization of the potential of any of these technologies faces a set of challenges related to medium access control (MAC) schemes. This work focuses on MAC schemes tailored for full‐duplex antennas, since they are expected to play a major role in the foreseeable 5G networks. In this context, this paper presents a MAC layer technique to improve total transmission time when full‐duplex antennas are employed. Several evaluations in different scenarios are conducted to assess the proposed MAC scheme. Numerical results show that the proposed scheme provides gains up to 156% when compared to a state‐of‐the‐art full‐duplex antenna MAC protocol. Compared to traditional half‐duplex antenna MAC protocols, the proposed scheme yields gain up to 412%.

Multichannel MAC Scheme to Deliver Real-Time Safety Packets in Dense VANET

Intelligent Transportation System (ITS) provides facility of driving assistance and multimedia services to the road users. To improve the Intelligent Transportation System, Vehicular Ad-Hoc Networks are the most prominent area that improve the services of ITS. Vehicular Ad-Hoc Networks apply multiple channel medium access control scheme according to the IEEE 1609.4 standard draft. According to the standard draft multiple channel medium access control scheme, channels are split into service channels (SCHs) and control channel (CCHs). This work proposes a dynamic control channel interval (DCI) MAC scheme that can variably fix the time interval between SCHs and CCH efficiently. This work divides the SCHs interval time into small interval time slots according to the current network traffic load.

Token-Based Adaptive MAC for a Two-Hop Internet-of-Things Enabled MANET

In this paper, a distributed token-based adaptive medium access control (TA-MAC) scheme is proposed for a two-hop Internet of Things (IoT)-enabled mobile ad hoc network. In the TA-MAC, nodes are partitioned into different one-hop node groups, and a time division multiple access (TDMA)-based superframe structure is proposed to allocate different TDMA time durations to different node groups to overcome the hidden terminal problem. A probabilistic token passing scheme is devised to distributedly allocate time slots to nodes in each group for packet transmissions, forming different token rings. The distributed time slot allocation is adaptive to variations of the number of nodes in each token ring due to node movement. To optimize the medium access control (MAC) design, performance analytical models are presented in closed-form functions of both MAC parameters and network traffic load. Then, an average end-to-end delay minimization framework is established to derive the optimal MAC parameters under a certain network load condition. Analytical and simulation results demonstrate that, by adapting the MAC parameters to the varying network condition, the TA-MAC achieves consistently minimal average end-to-end delay, bounded delay for local transmissions, and high aggregate throughput. Further, the performance comparison with other MAC schemes shows the scalability of the proposed MAC in an IoT-based two-hop environment with an increasing number of nodes.

3-ent (resilient, intelligent, and efficient) medium access control for full-duplex, jamming-aware, directional airborne networks

A novel medium access control (MAC) scheme is designed for the airborne networks with the following features: (1) Long-distance links, where the radio propagation delay cannot be ignored; (2) Use of nodes equipped with multi-beam antennas that can communicate on their multiple beams concurrently; (3) Full-duplex communication so that nodes can simultaneously send and receive data on its beams. Our MAC design has 3-ent properties (i.e., it is efficient, resilient, and intelligent). It achieves throughput-efficient communication through the integration of full duplex traffic control and multi-beam data forwarding. It is resilient to jamming attacks through the encoding of traffic in each beam. And, it uses the intelligent traffic prediction so that each beam can better prepare for communication based on the prediction of traffic and neighbor movement.

Medium access control schemes for flat mobile wireless sensor networks

One aspect of Mobile Wireless Sensor Networks (MWSNs) is the MAC protocol, which is critical in terms of reliability, delay and energy consumption. This work begins with a literature review, showing that the majority of MWSN MACs are designed for hierarchical architectures, demonstrating that there is a lack of MACs intended for flat architecture MWSNs. Subsequently, we propose three new MAC protocols, uniquely designed for flat MWSNs. Explicitly, the proposed MACs are Carrier Sense Multiple Access with Dedicated Slots, Network Division Multiple Access with Collision Avoidance and Network Division Multiple Access with Dedicated Slots, which are specifically designed to work with the state-of-the-art Location Aware Sensor Routing protocol. Extensive modelling and simulation is done in dense and sparse scenarios with varying traffic levels to evaluate the impact of the proposed from the perspective of both the link and network layers. Given the uniqueness of the proposed protocols, four well-known MACs are also included to give a performance reference to the results. The MAC results show that the collision-free protocols give the best reliability and that Global-TDMA consistently yields the highest level of throughput. This highlights the importance of taking into account both MAC and routing during the design process.

Link-Layer Cooperation Based on Distributed TDMA MAC for Vehicular Networks

Cooperative medium access control (MAC) protocols have been proposed for improving communication reliability and throughput in wireless networks. In our previous work, a cooperative MAC scheme called Cooperative ADHOC MAC (CAH-MAC) has been proposed to increase the network throughput under a static networking scenario for vehicular communications. In this paper, we study the effects of relative mobility among nodes and channel fading on the performance of CAH-MAC. In a dynamic networking environment, system performance degrades due to cooperation collisions. To tackle this challenge, we present an enhanced CAH-MAC (eCAH-MAC) scheme, which avoids cooperation collisions and efficiently utilizes cooperation opportunities without disrupting the time-slot reservation operations. Through mathematical analysis and computer simulations, we show that eCAH-MAC increases the effectiveness of node cooperation by increasing utilization of an unreserved time slot. Furthermore, we perform extensive simulations for realistic networking scenarios to investigate the probability of successful cooperative relay transmission and usage of unreserved time slots in eCAH-MAC, in comparison with existing approaches.

Influence of Duty-Cycled Wake-Up Receiver Characteristics on Energy Consumption in Single-Hop Networks

In sensor network applications with low traffic intensity, idle channel listening is one of the main sources of energy waste. The use of a dedicated low-power wake-up receiver (WRx), which utilizes duty-cycled channel listening, can significantly reduce the idle listening energy cost. Extreme low-power design typically leads to performance losses, indirectly increasing energy costs. Striking the right balance is, therefore, very important when introducing WRxs. We present a system analysis and heuristic parameter optimization for an existing duty-cycled WRx medium access control scheme. First, we introduce a framework for analysis of energy consumption and delay of an entire single-hop network where we include WRx characteristics. The WRx characteristics are condensed into two parameters: reduction in power consumption and associated loss of performance, compared with the main receiver. The analysis framework is used to find optimal wake-up beacon and protocol parameters for different WRx characteristics to minimize the total network energy consumption per data packet. The importance of the optimization is that it provides information on if, and how much, we can save in terms of energy by introducing a WRx with a certain characteristic. We also present accurate approximations of both optimal energy savings and resulting delays.

Cross-Network Performance Analysis of Network Coding Aided Cooperative Outband D2D Communications

In long term evolution advanced (LTE-A) networks, the mobile devices can concurrently participate in cooperative outband device-to-device (D2D) data exchange by virtue of user- or network-related parameters (e.g., interest in the same content and cooperative transmissions, respectively). In these scenarios, two major problems arise: 1) the coexistence of multiple devices creates channel access issues, demanding effective medium access control (MAC) schemes, and 2) cellular network factors (i.e., scheduling policy and channel conditions) affect the D2D communication, as the circulating information in D2D links is mainly of cellular network origination, stressing the need for cross network approaches. In this context, the contribution of this paper is threefold. First, exploiting idle devices as relays and the benefits of network coding (NC) in bidirectional communications, we propose an adaptive cooperative NC-based MAC (ACNC-MAC) protocol for the D2D data exchange. Then, we devise a cross-network model that captures the impact of cellular network characteristics on D2D communication. Finally, we evaluate the performance of the ACNC-MAC in terms of throughput, energy efficiency, and battery consumption. Our results show that the LTE-A parameters and the relays’ participation significantly affect the D2D throughput, while the D2D performance deteriorates with the increase of cell congestion.