MAC Protocol For Wireless Sensor Networks Research Articles

Transient Coordinator: a Collision Resolution Algorithm for Asynchronous MAC Protocols in Wireless Sensor Networks

Wireless sensor networks (WSN) often employ asynchronous MAC scheduling, which allows each sensor node to wake up independently without synchronizing with its neighbor nodes. However, this asynchronous scheduling may not deal with collisions due to hidden terminals effectively. Although most of the existing asynchronous protocols exploit a random back-off technique to resolve collisions, the random back-off cannot secure a receiver from potentially repetitive collisions and may lead to a substantial increase in the packet latency. In this paper, we propose a new collision resolution algorithm called Transient Coordinator (TC) for asynchronous WSN MAC protocols. TC resolves a collision on demand by ordering senders` transmissions when a receiver detects a collision. To coordinate the transmission sequence both the receiver and the collided senders perform handshaking to collect the information and to derive a collision-free transmission sequence, which enables each sender to exclusively access the channel. According to the simulation results, our scheme can improve the average per-node throughput by up to 19.4% while it also reduces unnecessary energy consumption due to repetitive collisions by as much as 91.1% compared to the conventional asynchronous MAC protocols. This demonstrates that TC is more efficient in terms of performance, resource utilization, and energy compared to the random back-off scheme in dealing with collisions for asynchronous WSN MAC scheduling.

무선 센서네트워크 환경에서 Duty Cycle 기반 동기식 및 비동기식 MAC 프로토콜의 에너지 성능과 지연시간에 대한 상호 분석

Recently, Wireless Sensor Networks (WSN) require energy performance and guaranteed delivery delay time, contrarily with previous MAC protocols that aim to high throughput mostly. In order to satisfy the new significant requirements, many MAC protocols of WSN employ and try to enhance the duty cycle mechanism which is energy efficient technique in MAC layer. This duty cycle mechanism is oriented by toggling the transceiver conditions composed of wakeup and sleep states. The synchronous MAC protocols perform the period synchronization process. Hence, these are energy efficient in periodic monitoring environment, but are inefficient in where an event is incurred rarely and infrequently. Otherwise, the performance of asynchronous MAC protocols are contrarily with synchronous protocols. In this paper, we design two models consisting Always-busy and Always-idle ti simplify the general network congestion conditions. Through these models, moreover, we analyze two types MAC protocols in terms of energy efficiency and delay performance by analytical results. Additionally, we also evaluate two MAC protocols with two gongestion models that we designed. By the analytical and simulated results, we provide the general and efficient decision method in which protocols are more appropriate in a certain WSN environment.

The Analysis and Improvement of S-MAC Protocol for Wireless Sensor Networks

Nowadays Wireless Sensor Networks (WSN) has been widely used because of its adaptability, mobility and scalability. The MAC protocol is one of the most important network protocols which guarantee the WSN communication efficiency. The major concern of this paper is the typical contention-based MAC protocol in WSN—the S-MAC protocol. Considering the backoff algorithm of S-MAC protocol cannot resolve the fairness problem for nodes communication, the BDQR (Backoff Depends on Queue and Retry) backoff algorithm was presented in this paper. The experimental results demonstrated that by using this algorithm, nodes communication fairness was improved, channel collisions were reduced while network lifespan was prolonged.

Adaptive WSN MAC Protocol Based on Mixing Broadcast

MAC protocol of Wireless Sensor Network (WSN) requires high efficiency to achieve maximum traffic transmission, while pursuit high reliability at the same time. The paper researched on reliable mixing broadcast implementation manner of WSN. Based on analysis on implementation manners of broadcast, unicast and mixing broadcast, a kind of adaptive MAC protocol supporting reliable mixing broadcast was presented. The protocol dynamically select implementation manner with maximum mixing broadcast efficiency based on given network parameters to complete transmission of data frame. Simulation results based on NS2 shows that the protocol has better performance to achieve reliable mixing broadcast, which solve problems of reliable broadcast/multicast at network layer.

An Energy-Efficient MAC Protocol in Wireless Sensor Networks: A Game Theoretic Approach

Game Theory provides a mathematical tool for the analysis of interactions between the agents with conflicting interests, hence it is well suitable tool to model some problems in communication systems, especially, to wireless sensor networks (WSNs) where the prime goal is tominimize energy consumption than high throughput and low delay. In this paper, we use the concept of incomplete cooperative game theory to model an energy efficient MAC protocol for WSNs. This allows us to introduce improved backoff algorithm for energy efficient MAC protocol in WSNs. Finally, our research results show that the improved back off algorithm can improve the overall performance as well as achieve all the goals simultaneously for MAC protocol in WSNs.

Performance Evaluation of Sensor Medium Access Control Protocol Using Coloured Petri Nets

Formal modeling techniques can be used for analysis of wireless sensor networks (WSNs). Coloured Petri nets (CPNs) that is an extension of Petri nets is a powerful modeling technique. In this paper, we present a CPN model for modeling and performance evaluation of a medium access control protocol in WSNs named sensor-medium access control protocol (S-MAC). S-MAC is an energy-aware MAC protocol with nodes scheduling. The proposed model for this protocol uses the hierarchical modeling capability of CPNs. By using CPNs in this case study and the proposed method for modeling packet broadcast, we have demonstrated the possibility of modeling and evaluation of any other MAC protocol in WSNs or mobile ad-hoc networks (MANET).

Energy and delay optimized contention for wireless sensor networks

In wireless sensor network (WSN) studies, the main objective is minimizing the energy consumption so that the lifetime is maximized under the limited battery capacity constraints. Additionally, in most event-driven WSN applications, the end-to-end delay, and hence, the medium access delay should be minimized. Majority of the WSN MAC protocols are contention-based wherein contention window size setting involves an important trade-off between the collision probability and idle listening durations in contentions where both are aimed to be lowered for efficient network operation. In this paper, the energy optimizing and the delay optimizing contention window sizes are derived as a function of the number of contending nodes. For this purpose, we present separate analyses for the contention delay and for the energy consumed which are verified with detailed simulations. In order to obtain close to optimal performance values in a distributed manner, we propose a method for estimating the number of contending nodes since the individual wireless sensor nodes do not have this information readily. Simulations of an event-driven WSN application verify that the proposed method successfully improve both delay and energy efficiency of the contention-based medium access. The end-to-end network performance is also investigated by employing a geographical routing protocol. Results show that using the heuristic method proposed that use the optimum contention window size analyses presented, the overall network performance can be improved without incurring any overhead to the system.

Overview of MAC Protocols in Wireless Sensor Networks

Wireless sensor networks(WSNs)are different from traditional networks and are highly dependent on appli- cations.One of the main goals of WSNs is to maximize the lifetime of the whole network as well as to use the constrained node resources efficiently,such as energy,memory,and computing capacities.Traditional MAC protocols cannot be applied efficiently to WSNs.Therefore,many new MAC protocols have been designed specifically according to WSNs characteristics and different applications.After introducing the characteristics of WSNs,this paper first describes the sensor network properties that are crucial to the design of MAC protocols.Then,the key mechanisms,virtues,and short- coming of the existing representative MAC protocols are analyzed,and their performances are compared.The results show that there is no MAC layer protocol that can be accepted as a standard.A good MAC protocol is that it has the ability to make tradeoffs between energy-efficiency and other performances of WSNs according to application conditions. Finally,the future research strategies and trends of MAC protocols in WSNs are summarized.

Energy-efficient link-layer jamming attacks against wireless sensor network MAC protocols

A typical wireless sensor node has little protection against radio jamming. The situation becomes worse if energy-efficient jamming can be achieved by exploiting knowledge of the data link layer. Encrypting the packets may help to prevent the jammer from taking actions based on the content of the packets, but the temporal arrangement of the packets induced by the nature of the protocol might unravel patterns that the jammer can take advantage of, even when the packets are encrypted. By looking at the packet interarrival times in three representative MAC protocols, S-MAC, LMAC, and B-MAC, we derive several jamming attacks that allow the jammer to jam S-MAC, LMAC, and B-MAC energy efficiently. The jamming attacks are based on realistic assumptions. The algorithms are described in detail and simulated. The effectiveness and efficiency of the attacks are examined. In addition, we validate our simulation model by comparing its results with measurements obtained from actual implementation on our sensor node prototypes. We show that it takes little effort to implement such effective jammers, making them a realistic threat. Careful analysis of other protocols belonging to the respective categories of S-MAC, LMAC, and B-MAC reveals that those protocols are, to some extent, also susceptible to our attacks. The result of this investigation provides new insights into the security considerations of MAC protocols.

A wireless sensor networks MAC protocol for real-time applications

Wireless sensor networks (WSN) are designed for data gathering and processing, with particular requirements: low hardware complexity, low energy consumption, special traffic pattern support, scalability, and in some cases, real-time operation. In this paper we present the virtual TDMA for sensors (VTS) MAC protocol, which intends to support the previous features, focusing particularly on real-time operation. VTS adaptively creates a TDMA arrangement with a number of timeslots equal to the actual number of nodes in range. Thus, VTS achieves an optimal throughput performance compared to TDMA protocols with fixed size of frame. The frame is set up and maintained by a distributed procedure, which allows sensors to asynchronously join and leave the frame. In addition, duty cycle is increased or decreased in order to keep latency constant below a given deadline. Therefore, a major advantage of VTS is that it guarantees a bounded latency, which allows soft real-time applications.

A cluster-based power-efficient MAC scheme for event-driven sensing applications

In developing an architecture for wireless sensor networks (WSNs) that is extensible to hundreds of thousands of heterogeneous nodes, fundamental advances in energy efficient communication protocols must occur. In this paper, we first propose an energy-efficient and robust intra-cluster communication bit-map assisted (BMA) MAC protocol for large-scale cluster-based WSNs and then derive energy models for BMA, conventional TDMA, and energy efficient TDMA (E-TDMA) using two different approaches. We use simulation to validate these analytical models. BMA is intended for event-driven sensing applications, that is, sensor nodes forward data to the cluster head only if significant events are observed. It has low complexity and utilizes a dynamic scheduling scheme. Clustering is a promising distributing technique used in large-scale WSNs, and when combined with an appropriate MAC scheme, high energy efficiency can be achieved. The results indicate that BMA can improve the performance of wireless sensor networks by reducing energy expenditure and packet latency. The performance of BMA as an intra-cluster MAC scheme relative to E-TDMA depends on the sensor node traffic offer load and several other key system parameters. For most sensor-based applications, the values of these parameters can be constrained such that BMA provides enhanced performance.