Collision-free MAC Research Articles

DC-MAC: A Delay-Aware and Collision-Free MAC Protocol Based on Game Theory for Underwater Wireless Sensor Networks

DC-MAC: A Delay-Aware and Collision-Free MAC Protocol Based on Game Theory for Underwater Wireless Sensor Networks

Collision-free and low delay MAC protocol based on multi-level quorum system in underwater wireless sensor networks

Underwater wireless sensor network (UWSN) is a typical application of wireless network in underwater environment, which mainly uses acoustic communication at present. However, due to the characteristics of high bit error rate, very limited bandwidth and high transmission delay, the data transmission collision of underwater communication is very serious. In order to reduce transmission collision and improve network performance, we propose a collision-free time slot scheduling MAC protocol based on multi-level quorum system for high loaded UWSNs. The proposed protocol can allocate different time slots for nodes in the same collision area, while realize space reuse for nodes in different collision areas. Considering the unbalanced data transmission of each node, a multi-level quorum system algorithm is constructed for fairness, which can allocate time slots on demand according to the data transmission amount of each node. In order to ensure reliable transmission of data, a light weight retransmission mechanism is designed to reduce the impact of long delay on channel duty cycle. Simulation results prove that the proposed MAC protocol can effectively avoid transmission collision, reduce transmission delay, improve system energy efficiency, and have good adaptability for different network topologies.

Design and Evaluation of Self Organizing, Collision Free MAC Protocol for Distributed Cognitive Radio Networks

A cognitive radio network has a high promise to improve spectrum utilization, through exploitation of spectrum holes from the primary network. However, in a distributed environment, employing contention based random access, collisions and unattempted slots result in waste of the discovered holes. This waste is even costlier for a CRN as resources are consumed in finding the holes. In this paper, we have proposed a self-organizing distributed CR-MAC protocol so that the contention is not required for medium access, thereby, minimizing the waste of opportunity due to collisions or for being left idle in random access, consequently, improving the spectral efficiency. This is achieved by organizing and queuing the active secondary users through a timer value and directing them in an orderly fashion to use the discovered holes. The proposed scheme successfully assigns a channel to more than 99% of the secondary users in less than 5% of the idle slots from the primary network, compared to that required in contention based random access schemes.

Fail silence mechanism for dependable vehicular communications

This paper presents a fault-tolerant architecture to improve the dependability of infrastructure-based vehicular networks. For that purpose, a fail silence enforcement mechanism for road-side units (RSUs) was designed, implemented and tested. Vehicular communications based on IEEE 802.11p are inherently non-deterministic. The presence of RSUs and a backhauling network, adds a degree of determinism that is useful to enforce real-time and dependability, both by providing global knowledge and by supporting the operation of collision-free deterministic MAC protocols. One of such protocols is V-FTT, for which the proposed mechanism was designed as a case study. Notice, however that this mechanism is protocol independent and can be adapted to any wireless communications system. The proposed technique is capable of validating a frame for transmission by identifying faults both in value and time domains. Experimental results show that the fail silence enforcement mechanism has low latency and consumes few FPGA resources.

A Novel Multi-Channel MAC Protocol for Cluster Based Wireless Multimedia Sensor Networks

An energy efficient, scalable and collision free MAC protocol, DTFMM, is presented in this paper, which combines frequency and time division principles for medium sharing. It is based on clustered network topology, and the protocol employs a distributed local coordinate algorithm for assigning channels among clusters to enable simultaneous non-interfering data collection. Intra-cluster transmissions are scheduled by cluster head (CH) based on time slot. CHs aggregate the gathered data and forward it over inter-CH paths to the base-station based on minimum spanning tree routing. Distinct channels are adopted by the independent branches of the inter-CH routing tree. Data transmission on a branch is further scheduled in depth-first ordering. DTFMM allows nodes to stay in sleeping mode for the longest duration and thus it minimizes energy consumption. Simulation demonstrated superiority of DTFMM in terms of convergent rate, throughput and delay performance when compared with well-known protocol MMSN.

Energy-aware node placement, topology control and MAC scheduling for wireless sensor networks

In the WSNs, the nodes closer to the sink node have heavier traffic load for packet forwarding because they do not only collect data within their sensing range but also relay data for nodes further away. The unbalanced power consumption among sensor nodes may cause network partition. This paper proposes efficient node placement, topology control, and MAC scheduling protocols to prolong the sensor network lifetime, balance the power consumption of sensor nodes, and avoid collision. Firstly, a virtual tree topology is constructed based on Grid-based WSNs. Then two node-placement techniques, namely Distance-based and Density-based deployment schemes, are proposed to balance the power consumption of sensor nodes. Finally, a collision-free MAC scheduling protocol is proposed to prevent the packet transmissions from collision. In addition, extension of the proposed protocols are made from a Grid-based WSN to a randomly deployed WSN, enabling the developed energy-balanced schemes to be generally applied to randomly deployed WSNs. Simulation results reveal that the developed protocols can efficiently balance each sensor node's power consumption and prolong the network lifetime in both Grid-based and randomly deployed WSNs.

Collision Free MAC Protocols for Wireless Ad Hoc Networks based on BIBD Architecture

Wireless Ad hoc networks represent a powerful telecommunication infrastructure that is being exploited for enabling general wireless networking connectivity for a variety of significant applications, e.g., military applications, industrial automation, sensor networks, vehicular networks, applications in case of disaster, etc. The distributed and flexible architecture of wireless ad hoc networks is a key factor, however, their wide deployment relies on protocols able to provide energetic optimization, high channel utilization, support for real time traffic, etc. In such a context, recently a Collision Free MAC protocol (CF- MAC), based on the theory of Balanced Incomplete Block Design (BIBD), has been proposed. Its effectiveness has been already investigated showing significant improvements compare d to the Standard IEEE 802.11, in terms of throughput, one -way packet delay, energy consumption and support of real time traffic. In this paper enhanced versions of CF -MAC have been considered with significant novelties regarding the introduction of variab le time slot dimension, different management of Power Saving (PS) mechanisms, more efficient utilization of channel bandwidth, etc. The performance of these variants have been investigated by simple analytical models, in terms of energy saving, channel utilization, average access delay, etc., highlighting their improvements over basic CF-MAC protocol. In addition, computer simulations have been exploited to study the suitability of the proposed schemes to support VoIp applications.

Provisioning link layer proportional service differentiation in wireless networks with smart antennas

In this paper, we present a collision free MAC protocol for wireless networks with smart antennas that provides proportional service differentiation to various classes of traffic based on their respective bandwidth demand. The proposed protocol works for diverse physical parameters such as number of interfaces at each node, number of communication frequencies, and antenna beamwidth. To the best of our knowledge, this is the first work that provides link layer differentiated services for wireless networks with smart antennas and explores the influence of the physical parameters and network topology on the performance of the MAC layer.

An energy-efficient, scalable and collision-free MAC layer protocol for wireless sensor networks

Wide range of applications such as disaster management, military and security have fueled the interest in sensor networks during the past few years. Sensors are typically capable of wireless communication and are significantly constrained in the amount of available resources such as energy, storage and computation. Such constraints make the design and operation of sensor networks considerably different from contemporary wireless networks, and necessitate the development of resource conscious protocols and management techniques. In this paper, we present an energy-efficient, scalable and collision-free MAC layer protocol for sensor networks. The approach promotes time-based arbitration of medium access to limit signal interference among the transmission of sensors. Transmission and reception time slots are prescheduled to allow sensors to turn their radio circuitry off when not engaged. In addition, energy consumption due to active to sleep mode transitions is minimized through the assignment of contiguous transmission/reception slots to each sensor. Scalability of the approach is supported through grouping of sensors into clusters. We describe an optimization algorithm for energy conscious scheduling of time slots that prevents intra-cluster collisions and eliminates packet drop due to buffer size limitations. In addition, we also propose an arbitration scheme that prevents collisions among the transmission of sensors in different clusters. The impact of our approach on the network performance is qualified through simulation.. Copyright © 2004 John Wiley & Sons, Ltd.

A scalable and collision-free MAC protocol for all-optical ring networks

In this paper, we propose a collision free MAC protocol for an all-optical WDM ring network where packets remain in optical domain from source to destination. The protocol prevents the contention for shared data-channels and the destination by sharing global status information among the nodes. The proposed protocol which we call reserve–transmit–release (RTR) is based on a reservation scheme and requires no synchronization among the nodes. The node architecture in this scheme uses a tunable transceiver and, thus, makes the scheme scalable. We study the performance of the algorithm by network simulation. We consider both the Poisson and Pareto distributions for modeling the traffic. We present results for both the models and compare. It is observed that the delay is much higher for bursty traffic and the performance degrades gracefully with increase in nodes as well as the traffic.

All-optical WDM multi-rings with differentiated QoS

This article considers all-optical WDM networks based on a slotted multichannel ring topology, where nodes are equipped with one fixed-wavelength receiver and one wavelength-tunable transmitter; and shows how to design very effective MAC protocols that provide packet-mode transport to multiple information flows with different QoS requirements. As an example, we describe SR3, a collision-free slotted MAC protocol which combines a packet scheduling strategy (called SRR), a fairness control algorithm (called MMR); and a reservation mechanism. SRR achieves an efficient exploitation of the available bandwidth, MMR guarantees fair throughput access to each node, and SR3, by permitting slot reservations, leads to tighter control on access delays, and can thus effectively support traffic classes with different QoS requirements.