Energt Efficient MAC Protocols for Wireless Sensor Network: A Survey
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paper_title: Coordination in a multi-robot surveillance application using Wireless Sensor Networks

paper_content:

Cooperative robots and their integration with Wireless Sensor Networks (WSNs) is an expanding area that still deserves significant research efforts. This paper presents a multi-robot surveillance application supported by a WSN. We investigate the problem of multi-robot coordination for target tracking and capturing. One key distinction of our problem model is to consider a WSN that supports the mission of the multi-robot team. We devised three mechanisms: centralized, distributed and market-based algorithms, which were extensively evaluated under the Player/Stage simulator. Simulation results show that the centralized approach is the most likely solution able to maintain an efficient system cost.
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paper_title: A survey on power-efficient MAC protocols for wireless body area networks

paper_content:

Design of power-efficient medium access control (MAC) protocols in wireless body area networks (WBANs) is important as it helps to prolong the network lifetime. This paper attempts to survey recent works of power efficient MAC protocols for WBANs and presents a comparison of the approaches pursued. We investigate a few MAC protocols devised for WBAN by highlighting their salient features. Finally, a number of open research issues are discussed.
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paper_title: Wireless Sensor Network for Crop Field Monitoring

paper_content:

This paper presents the design and the implementation of a Wireless Sensor Network that can monitor the air temperature, humidity and ambient light intensity in a crop field. This can help the end users such as farmers in the better understanding of agriculture practices to be adopted for crop management. Since, early detection of plant fires is necessary to prevent high crop damages; a plant fire detection scheme has also been incorporated in the system. The system consists of nodes, which are equipped with small size application specific sensors and radio frequency modules. The sensor data is transmitted via radio frequency link to the centrally localized computer terminal for data logging and analysis. The design also includes an alternative scheme for the storage of sensor data into an EEPROM in case the computer terminal switches OFF like in the case of a power failure. The sensor nodes can additionally be programmed from the computer terminal itself according to the changing needs of farmers, thus preventing the need for a redeployment of the Wireless Sensor Network every time some changes are to be made. The Graphical User Interface has been made very user-friendly keeping in mind that the system will be used predominantly by the farmers. Since energy is the main operating constraint, sleep mode of the core components is utilized. The system design implemented addresses a wide range of agricultural concerns from detecting sensor node failure, retasking the sensor nodes, power management and data reliability considerations. The proposed system has been deployed in a brinjal field and the feasibility of the network is tested by evaluating the field results.
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paper_title: A New Contention Access Method for Collision Avoidance in Wireless Sensor Networks

paper_content:

In this paper, we present a new contention access method for scalable wireless sensor networks. In these networks, the traffic levels are often variants, particularly in monitoring applications. Sensors do not regularly have much data to send. However, when an event occurs, every sensor in a given area will send its alert to the access point simultaneously. Hence, this network suffers a huge number of communications at the same time. In fact, at an instant, only one transmission is permitted among interfering nodes. If there are more than two transmissions at the same time, there will be a collision. Therefore, this variant communication of wireless sensor networks leads to an increase in collision and energy consumption. Traditional wireless network uses an exponential back-off scheme to react to collision. However, this scheme is designed for traditional wireless networks and is not well adapted to wireless sensor networks. Our proposal uses a dynamical change of channel access probability which can reduce the number of contention times and collisions. Moreover, it can be applied in any existing MAC protocol of wireless sensor network.
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paper_title: Performance analysis of an adaptive, energy-efficient MAC protocol for wireless sensor networks

paper_content:

We propose an adaptive and energy-efficient TDMA-based MAC protocol that significantly reduces energy consumption in the network, while efficiently handling network traffic load variations and optimizing channel utilization through a timeslot stealing mechanism and a timeslot reassignment procedure. We have analytically derived the average delay performance of our MAC protocol, with and without the timeslot stealing mechanism. Our delay model, validated via simulations, shows that the timeslot stealing mechanism can substantially improve the protocol throughput in scenarios with varying and asymmetric traffic patterns. Evaluation results show that the timeslot reassignment procedure is efficient in handling the longer timescale changes in the traffic load, while the timeslot stealing mechanism is better in handling the shorter timescale changes in the traffic patterns.
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paper_title: A novel energy efficient chain based hierarchical routing protocol for wireless sensor networks

paper_content:

The nodes in a sensor network are severely constrained by energy. Reducing the energy consumption of the nodes to prolong the network lifetime is considered a critical challenge while designing a new routing protocol. In this paper we propose a new power-aware, adaptive, hierarchical and chain based protocol — CCPAR (Clustered Chain based Power Aware Routing) that utilizes the periodic assignments of the cluster head role to different nodes based on the highest residual battery capacity for ensuring the even dissipation of power by all the nodes. Transmission from a single cluster head to the base station in each round and the distribution of the data aggregation workload among all the nodes, save the cluster heads from early exhaustion. The use of data aggregation also reduces the amount of information to be transmitted to the base station. By chaining the nodes in each cluster and using a separate chain for the cluster heads, CCPAR offers the advantage of small transmit distances for most of the nodes and thus helps them to be operational for a longer period of time by conserving their limited energy. The simultaneous construction of multiple chains in different clusters reduces the time for chain construction as well as the length of each of the chains. These shorter length chains solve the problem of excessive delay in transmission for the distant nodes. Use of a fresh set of parameter values in each round provides the users the flexibility to change these values in a way to control the power consumption. The introduction of MAX threshold enables CCPAR to be quickly responsive and thus highly suitable for time critical applications. From the performance evaluation we observe that CCPAR outperforms other protocols in terms of energy saving and longevity of the network.
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paper_title: Development of a WSN integrated weather station node for an irrigation alert program under Tunisian conditions

paper_content:

Recent advances in sensor and wireless radio frequency (RF) technologies offer vast opportunities for development and application of sensor systems for agriculture. It is the concept of precision agriculture, where Wireless Sensor Networks (WSN) is playing an important part in the handling and managing of water resources for irrigation, in understanding the changes in the crops to assess the optimum point for harvesting, in estimating fertilizers requirements and to predict crop performance more accurately. The field micro-climate monitoring is important for crop water requirements determination. Traditional weather stations are expensive, on demand data collection and not flexible for new sensors addition or WSN integration. This paper aims at the design of a custom low-cost Weather Station hardware and software node (WS-node) for irrigation scheduling in developing countries context. These sensors data are transmitted to the DSS (Decision Support System) in a Wireless Sensor Networks (WSN) infrastructure, taking into account all particularities of such environments constraints. Cost factors, field conditions, farmer knowledge, devices availability are the most important ones.
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paper_title: A detailed review of energy-efficient medium access control protocols for mobile sensor networks

paper_content:

This article reviews the state-of-the-art energy-efficient contention-based and scheduled-based medium access control (MAC) protocols for mobile sensor networks (MSNs) by first examining access schemes for wireless sensor networks (WSNs). Efficient and proper mobility handling in sensor networks provides a window of opportunity for new applications. Protocols, such as S-MAC, reduce energy consumption by putting nodes to sleep after losing to channel contention or to prevent idling. Sleeping is a common method for energy-efficient MAC protocols, but delay depends on sleep duration or frame time, and longer delays lead to higher packet lost rate when nodes are unsynchronized due to network mobility. MS-MAC extends S-MAC to include mobility-awareness by decreasing this sleep duration when mobility is detected. S-MAC with extended Kalman filter (EKF) reduces mobility-incurred losses by predicting the optimal data frame size for each transmission. MMAC utilizes a dynamic mobility-adaptive frame time to enhance TRAMA, a scheduled-based protocol, with mobility prediction. Likewise, G-MAC utilizes TDMA for cluster-based WSNs by combining the advantages of contention and contention-free MACs. Z-MAC also combines both methods but without clustering and allows time slot re-assignments during significant topology changes. All of the above MAC protocols are reviewed in detail.
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paper_title: Practical data compression in wireless sensor networks: A survey

paper_content:

Power consumption is a critical problem affecting the lifetime of wireless sensor networks. A number of techniques have been proposed to solve this issue, such as energy-efficient medium access control or routing protocols. Among those proposed techniques, the data compression scheme is one that can be used to reduce transmitted data over wireless channels. This technique leads to a reduction in the required inter-node communication, which is the main power consumer in wireless sensor networks. In this article, a comprehensive review of existing data compression approaches in wireless sensor networks is provided. First, suitable sets of criteria are defined to classify existing techniques as well as to determine what practical data compression in wireless sensor networks should be. Next, the details of each classified compression category are described. Finally, their performance, open issues, limitations and suitable applications are analyzed and compared based on the criteria of practical data compression in wireless sensor networks.
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paper_title: Rehabilitation supervision using wireless sensor networks

paper_content:

Wireless sensor networks are becoming a topic of great interest in medical applications generating a large amount of work in medical and computer research communities. In this line, several solutions have been proposed to provide unobtrusive, flexible and low cost systems for patient supervision. However, existing solutions can not be used in rehabilitation supervision because of the specific characteristics of this application. Indeed, new major challenges arise from the fact that each sensor node needs to continuously stream large volumes of data at a high rate to enable doctors to extract clinically relevant information. In addition, the placement of several adjacent sensor nodes on the body may cause serious interferences problems. In this work, we describe and demonstrate our wireless sensor network prototype for high-fidelity rehabilitation supervision. Our demonstration allows attendees to experience the potential of wireless sensor networks for enabling flexible and low cost rehabilitation monitoring systems. In order to alleviate transmission problems, we develop a novel communication protocol that meets the clinical requirements of rehabilitation supervision in terms of data quality and data rate.
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paper_title: Wireless Communications

paper_content:

"Professor Andreas F. Molisch, renowned researcher and educator, has put together the comprehensive book, Wireless Communications. The second edition, which includes a wealth of new material on important topics, ensures the role of the text as the key resource for every student, researcher, and practitioner in the field."Professor Moe Win, MIT, USAWireless communications has grown rapidly over the past decade from a niche market into one of the most important, fast moving industries. Fully updated to incorporate the latest research and developments, Wireless Communications, Second Edition provides an authoritative overview of the principles and applications of mobile communication technology.The author provides an in-depth analysis of current treatment of the area, addressing both the traditional elements, such as Rayleigh fading, BER in flat fading channels, and equalisation, and more recently emerging topics such as multi-user detection in CDMA systems, MIMO systems, and cognitive radio. The dominant wireless standards; including cellular, cordless and wireless LANs; are discussed.Topics featured include: wireless propagation channels, transceivers and signal processing, multiple access and advanced transceiver schemes, and standardised wireless systems.Combines mathematical descriptions with intuitive explanations of the physical facts, enabling readers to acquire a deep understanding of the subject.Includes new chapters on cognitive radio, cooperative communications and relaying, video coding, 3GPP Long Term Evolution, and WiMax; plus significant new sections on multi-user MIMO, 802.11n, and information theory.Companion website featuring: supplementary material on 'DECT', solutions manual and presentation slides for instructors, appendices, list of abbreviations and other useful resources.
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paper_title: A survey of military applications of wireless sensor networks

paper_content:

This paper presents an overview of defense related applications of wireless sensor networks (WSNs). The operational context of modern military engagement has diversified into four scenarios, which set requirements and constraints upon applications of WSNs. The sensor types and their capabilities determine and constrain the application of WSNs. We classify military applications of WSNs according to operation scenarios and sensor types, and describe key classes. We also discuss research and engineering issues for future generations of military WSN applications.
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paper_title: A low overhead wireless sensor networks MAC protocol

paper_content:

Energy efficiency is the kernel issue in the designing of wireless sensor network(WSN) MAC protocols. S-MAC is a WSN MAC protocol based on the listen and sleep mechanism to reduce energy consumption. Synchronous frame in S-MAC protocol belongs to control information, so it's better to reduce it as much as possible. In addition, S-MAC protocol adopts virtual cluster synchronization mechanism which leads to the generation of border nodes, and the border nodes will exhaust energy more easily and earlier. This paper analyzed S-MAC, and proposed LO-MAC protocol. The LO-MAC protocol improved S-MAC by decreasing the control energy consumption and thus prolong network lifetime compared with S-MAC protocol, furthermore, it resolved the problem of border nodes. The simulation of S-MAC protocol and LO-MAC protocol energy efficient on NS2 improved that LO-MAC protocol was more energy efficient than S-MAC.
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paper_title: Design, development and testing of a wireless sensor network for medical applications

paper_content:

Due to the aging population issue and a shortage of health workers around the world, the demand of automatic patient monitoring systems is expected to increase in the near future. Wireless sensor networks have been recently used in many medical applications because of their properties such as low-power consumption, low cost and large network size. The objective of this research is to develop an automatic patient monitoring system to facilitate the real time monitoring of patients. The wireless medical sensor network has been designed and implemented using microcontroller CC2430 from Texas Instruments. Electrocardiogram sensor and triaxis accelerometer are deployed on the sensor node.
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paper_title: MAC Essentials for Wireless Sensor Networks

paper_content:

The wireless medium being inherently broadcast in nature and hence prone to interferences requires highly optimized medium access control (MAC) protocols. This holds particularly true for wireless sensor networks (WSNs) consisting of a large amount of miniaturized battery-powered wireless networked sensors required to operate for years with no human intervention. There has hence been a growing interest on understanding and optimizing WSN MAC protocols in recent years, where the limited and constrained resources have driven research towards primarily reducing energy consumption of MAC functionalities. In this paper, we provide a comprehensive state-of-the-art study in which we thoroughly expose the prime focus of WSN MAC protocols, design guidelines that inspired these protocols, as well as drawbacks and shortcomings of the existing solutions and how existing and emerging technology will influence future solutions. In contrast to previous surveys that focused on classifying MAC protocols according to the technique being used, we provide a thematic taxonomy in which protocols are classified according to the problems dealt with. We also show that a key element in selecting a suitable solution for a particular situation is mainly driven by the statistical properties of the generated traffic.
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paper_title: Review: A survey on coverage and connectivity issues in wireless sensor networks

paper_content:

A wireless sensor network (WSN) is composed of a group of small power-constrained nodes with functions of sensing and communication, which can be scattered over a vast region for the purpose of detecting or monitoring some special events. The first challenge encountered in WSNs is how to cover a monitoring region perfectly. Coverage and connectivity are two of the most fundamental issues in WSNs, which have a great impact on the performance of WSNs. Optimized deployment strategy, sleep scheduling mechanism, and coverage radius cannot only reduce cost, but also extend the network lifetime. In this paper, we classify the coverage problem from different angles, describe the evaluation metrics of coverage control algorithms, analyze the relationship between coverage and connectivity, compare typical simulation tools, and discuss research challenges and existing problems in this area.
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paper_title: A Survey of MAC Protocols for Mission-Critical Applications in Wireless Sensor Networks

paper_content:

Wireless Sensor Networks (WSNs) are generally designed to support applications in long-term deployments, and thus WSN protocols are primarily designed to be energy efficient. However, the research community has recently explored new WSN applications such as industrial process automation. These mission-critical applications demand not only energy efficient operation but also strict data transport performance. In particular, data must be transported to a sink in a timely and reliable fashion. Both WSN's data transport performance and energy consumption pattern are mainly defined by the employed medium access control (MAC) protocol. Therefore, this survey paper explores to what extent existing MAC protocols for WSNs can serve mission-critical applications. The reviewed protocols are classified according to data transport performance and suitability for mission-critical applications. The survey reveals that the existing solutions have a number of limitations and only a few recently developed MAC protocols are suitable for this application domain.
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paper_title: The Evolution of MAC Protocols in Wireless Sensor Networks: A Survey

paper_content:

Wireless Sensor Networks (WSNs) have become a leading solution in many important applications such as intrusion detection, target tracking, industrial automation, smart building and so on. Typically, a WSN consists of a large number of small, low-cost sensor nodes that are distributed in the target area for collecting data of interest. For a WSN to provide high throughput in an energy-efficient way, designing an efficient Medium Access Control (MAC) protocol is of paramount importance because the MAC layer coordinates nodes' access to the shared wireless medium. To show the evolution of WSN MAC protocols, this article surveys the latest progresses in WSN MAC protocol designs over the period 2002-2011. In the early development stages, designers were mostly concerned with energy efficiency because sensor nodes are usually limited in power supply. Recently, new protocols are being developed to provide multi-task support and efficient delivery of bursty traffic. Therefore, research attention has turned back to throughput and delay. This article details the evolution of WSN MAC protocols in four categories: asynchronous, synchronous, frame-slotted, and multichannel. These designs are evaluated in terms of energy efficiency, data delivery performance, and overhead needed to maintain a protocol's mechanisms. With extensive analysis of the protocols many future directions are stated at the end of this survey. The performance of different classes of protocols could be substantially improved in future designs by taking into consideration the recent advances in technologies and application demands.
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paper_title: Dynamic and Heterogeneous Wireless Sensor Networks for Virtual Instrumentation Services: Application to Perishable Goods Surveillance

paper_content:

Wireless sensor networks (WSNs) have gained an increasing interest in logistic applications. In this paper, we propose a universal hardware and software architecture to measure environmental variables in a dynamic heterogeneous plug-and-play WSN. In this framework the physical structure of the WSN is automatically and transparently generated from the final user. Each node of the WSN communicates through a middle level configurable service-oriented layer. Composition of these services defines high-level virtual instruments for the final user. The proposed WSN is able to configure dynamically these virtual links to achieve the user requirements. The reported strategy is aimed at giving support to collaborative systems, e.g. stock management, intelligent machinery, etc, performing their commanded tasks within indoor environments. To demonstrate the applicability of the proposed method, the paper presents a particular implementation of the described architecture in an intelligent transportation system where both surveillance and control tasks of perishable goods are required.
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paper_title: HomeWeb: An application framework for Web-based smart homes

paper_content:

Household appliances are being equipped with embedded micro-controllers and wireless transceivers, offering smart behavior. These augmented appliances form wireless networks and transform residential areas into smart homes. Advancements such as the effective penetration of the Internet in embedded computing and the promising practice of the Web of Things, allow the realization of Web-oriented smart homes. In a previous work, we developed a Web-based application framework for smart homes, supporting concurrent interaction from multiple family members. In this paper, we improve the functionality of our system by including a 6LoWPAN-based wireless sensor network inside the home environment, addressing issues such as device discovery and service description. Web techniques such as HTTP caching and push messaging, facilitate the efficient operation of a fully Web-based smart home. Through a technical evaluation, we show the benefits of directly Web-enabling embedded sensors in terms of performance and energy conservation. The development of a Web-based graphical application abstracts home automation procedure for typical residents.
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paper_title: A MAC scheme for avoiding inter-cluster collisions in wireless sensor networks

paper_content:

Recently, TDMA-based MAC protocols have been discussed in WSNs for their energy-efficient performance. In the use of TDMA-based MAC scheme, radios of sensors can be turned off during idle times in order to conserve energy. Clustering is an effective method for achieving high levels of energy efficiency and scalability, and is often combined with TDMA-based schemes to reduce the cost of idle listening. But, conventional TDMA protocols focus on intra-cluster communication MAC control. They don't consider collisions occurring among inter-clusters in developing architecture for WSNs that is extensible to hundreds of thousands of nodes. This paper proposes a TDMA based MAC protocol for avoiding inter-cluster collisions which avoids collisions occurring among clusters.
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paper_title: An agent-based signal processing in-node environment for real-time human activity monitoring based on wireless body sensor networks

paper_content:

Nowadays wireless body sensor networks (WBSNs) have great potential to enable a broad variety of assisted living applications such as human biophysical/biochemical control and activity monitoring for health care, e-fitness, emergency detection, emotional recognition for social networking, security, and highly interactive games. It is therefore important to define design methodologies and programming frameworks which enable rapid prototyping of WBSN applications. Several effective application development frameworks have been already proposed for WBSNs designed for TinyOS-based sensor platforms, e.g. CodeBlue, SPINE, and Titan. In this paper we present an application of MAPS, an agent framework for wireless sensor networks based on the Java-programmable Sun SPOT sensor platform, for the development of a real-time WBSN-based system for human activity monitoring. The agent-oriented programming abstractions provided by MAPS allow effective and rapid prototyping of the sensor-side software. In particular, the architecture of the developed system is a typical star-based WBSN composed of a coordinator node and two sensor nodes located respectively on the waist and the thigh of the monitored assisted living. The coordinator relies on a JADE-based enhancement of the SPINE coordinator and allows configuring sensors, receiving their data, and recognizing pre-defined human activities. On the other hand, each sensor node runs a MAPS-based agent that performs sensing of the 3-axial accelerometer sensor, computation of significant features on the acquired data, feature aggregation and transmission to the coordinator. The experimentation phase of the prototype, which allows evaluating the obtainable monitoring performances and activity recognition accuracy, is described. Moreover, a comparison of the monitoring system based on MAPS, AFME and SPINE in terms of programming effectiveness and system performances is discussed.
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paper_title: Effective Energy Management in Routing Protocol for Wireless Sensor Networks

paper_content:

Nodes sensors of a wireless sensor networks (WSNs) are powered by exhaustible batteries with limited life duration and generally non-rechargeable. As the deployment of these WSNs occurs in harsh areas generally inaccessible and sometimes hostile, the replacement of depleted batteries is not feasible, so nodes must therefore ensure their mission with their unique initial strict energy budget. This constraint makes the energy resource the most decisive and of critical importance in the WSNs. As data routing constitutes a basic service and that the communication is the activity with the highest energy consumption, the routing protocols have then paid and continue to pay much attention in this context of energy conservation. In this paper, we propose a multi hops routing protocol: PEGASIS-MH minimizing energy consumption and extending the network life time. This new protocol is a combination more efficient of the well known protocols hierarchical LEACH and PEGASIS. The results obtained through the simulations carried out in an environment of the simulator NS2 have shown that the performances achieved by our proposal are noteworthy and outperform those of the original protocols.
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paper_title: Trading latency for load balancing in many-to-one wireless networks

paper_content:

Wireless networks that combine a many-to-one traffic flow with multi-hop communication suffer from a funnelling effect that inevitably overburdens nodes closer to the base station. In sensor networks this is known as the energy hole problem. A routing protocol that constructs a shortest path tree exacerbates this problem by leaving some of the most critical nodes with more descendants than others and hence more relaying work to do. In this paper we propose a novel, fully distributed tree construction algorithm for building a load-balanced tree. Our algorithm, Degree Constrained Routing (DECOR), trades off latency for load balancing. We simulated the algorithm using a sensor network as an example. The results show that a small increase in latency, of less than 10%, can be sacrificed for a larger increase in balance of up to 80%. The lifetime of a sensor network using DECOR can be extended by up to 150% compared to the next best algorithm.
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paper_title: Algorithm for data similarity measurements to reduce data redundancy in wireless sensor networks

paper_content:

Extending the lifetime of wireless sensor networks remains the most challenging and demanding requirement that impedes large-scale deployments. The basic operation in WSNs is the systematic gathering and transmission of sensed data to a base station for further processing. During data gathering, the amount of data can be large sometimes, due to redundant data combined from different sensing nodes in the neighborhood. Thus the data gathered need to be processed before being transmitted, in order to detect and remove redundancy, which can impact the communication traffic and energy consumption of the network in a negative way. In this paper, we propose an algorithm to measure similarity between the data collected toward the base station(relative to a specific event monitoring), so that an aggregator sensor sends a minimum amount of information to the base station in a way that the latter can deduce the source information of sensing neighbors nodes. Further, our experimental results demonstrate that the communication traffic and the number of bits transmitted can be minimized while preserving accuracy on the base station estimations.
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paper_title: DCW-MAC: An Energy Efficient Medium Access Scheme Using Duty-Cycled Low-Power Wake-Up Receivers

paper_content:

In this work we present a new low-power medium access scheme for sensor-type networks specifically with low traffic intensity. We call the proposed scheme DCW-MAC where ultra-low-power wake-up receivers are combined with optimal duty-cycled listening. First we introduce a framework for the analysis of energy consumption of the studied network type, then we use it to optimize the MAC scheme to achieve very low total energy consumption per transmitted data packet. It is shown that even with large sacrifices in terms of wake-up receiver detection performance, required to achieve ultra-low-power consumption with a limited form factor, we can achieve very competitive total energy consumption and outperform other MAC schemes for scenarios with low traffic.
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paper_title: A review on energy efficient MAC protocols for wireless LANs

paper_content:

Energy efficiency is a major issue in any wireless networks. Medium access control (MAC) protocols play an important role in providing a fair and efficient allocation of the available bandwidth. Although a lot of research has been conducted on MAC protocols, the various issues involved have mostly been presented in isolation to each other. In this paper, we present a comprehensive review of energy efficiency MAC protocols for wireless LANs, integrating the issues and the challenges. We also present a classification of MAC protocols, based on the energy-efficiency, and describe them briefly.
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paper_title: MAC Essentials for Wireless Sensor Networks

paper_content:

The wireless medium being inherently broadcast in nature and hence prone to interferences requires highly optimized medium access control (MAC) protocols. This holds particularly true for wireless sensor networks (WSNs) consisting of a large amount of miniaturized battery-powered wireless networked sensors required to operate for years with no human intervention. There has hence been a growing interest on understanding and optimizing WSN MAC protocols in recent years, where the limited and constrained resources have driven research towards primarily reducing energy consumption of MAC functionalities. In this paper, we provide a comprehensive state-of-the-art study in which we thoroughly expose the prime focus of WSN MAC protocols, design guidelines that inspired these protocols, as well as drawbacks and shortcomings of the existing solutions and how existing and emerging technology will influence future solutions. In contrast to previous surveys that focused on classifying MAC protocols according to the technique being used, we provide a thematic taxonomy in which protocols are classified according to the problems dealt with. We also show that a key element in selecting a suitable solution for a particular situation is mainly driven by the statistical properties of the generated traffic.
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paper_title: Dynamic Duty-Cycle Scheduling Schemes for Energy-Harvesting Wireless Sensor Networks

paper_content:

In this letter, we propose two novel dynamic duty-cycle scheduling schemes (called DSR and DSP) in order to reduce sleep latency, while achieving balanced energy consumption among sensor nodes in wireless sensor networks (WSNs) with energy harvesting capability. In DSR, each sensor node is allowed to adjust its duty-cycle according to the current amount of residual energy only. Since the residual energy of nodes in energy-harvesting WSNs can increase over time due to their harvesting opportunity, the estimation of prospective increase in their residual energy is useful to achieve our goal. Hence, DSP allows each of sensor nodes to reduce its duty-cycle more aggressively in proportion to such an increase. Through NS-2 simulations, we verified that our proposed schemes outperform the duty-cycle scheduling scheme used in a representative existing MAC protocol such as RI-MAC.
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paper_title: On Reliable Broadcast in Low Duty-Cycle Wireless Sensor Networks

paper_content:

Broadcast is one of the most fundamental services in wireless sensor networks (WSNs). It facilitates sensor nodes to propagate messages across the whole network, serving a wide range of higher level operations and thus being critical to the overall network design. A distinct feature of WSNs is that many nodes alternate between active and dormant states, so as to conserve energy and extend the network lifetime. Unfortunately, the impact of such cycles has been largely ignored in existing broadcast implementations that adopt the common assumption of all nodes being active all over the time. In this paper, we revisit the broadcast problem with active/dormant cycles. We show strong evidence that conventional broadcast approaches will suffer from severe performance degradation, and, under low duty cycles, they could easily fail to cover the whole network in an acceptable time frame. To this end, we remodel the broadcast problem in this new context, seeking a balance between efficiency and latency with coverage guarantees. We demonstrate that this problem can be translated into a graph equivalence, and develop a centralized optimal solution. It provides a valuable benchmark for assessing diverse duty-cycle-aware broadcast strategies. We then extend it to an efficient and scalable distributed implementation, which relies on local information and operations only, with built-in loss compensation mechanisms. The performance of our solution is evaluated under diverse network configurations. The results suggest that our distributed solution is close to the lower bounds of both time and forwarding costs, and it well resists to the wireless loss with good scalability on the network size and density. In addition, it enables flexible control toward the quality of broadcast coverage.
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paper_title: A survey on power-efficient MAC protocols for wireless body area networks

paper_content:

Design of power-efficient medium access control (MAC) protocols in wireless body area networks (WBANs) is important as it helps to prolong the network lifetime. This paper attempts to survey recent works of power efficient MAC protocols for WBANs and presents a comparison of the approaches pursued. We investigate a few MAC protocols devised for WBAN by highlighting their salient features. Finally, a number of open research issues are discussed.
---
paper_title: Wireless Communications

paper_content:

"Professor Andreas F. Molisch, renowned researcher and educator, has put together the comprehensive book, Wireless Communications. The second edition, which includes a wealth of new material on important topics, ensures the role of the text as the key resource for every student, researcher, and practitioner in the field."Professor Moe Win, MIT, USAWireless communications has grown rapidly over the past decade from a niche market into one of the most important, fast moving industries. Fully updated to incorporate the latest research and developments, Wireless Communications, Second Edition provides an authoritative overview of the principles and applications of mobile communication technology.The author provides an in-depth analysis of current treatment of the area, addressing both the traditional elements, such as Rayleigh fading, BER in flat fading channels, and equalisation, and more recently emerging topics such as multi-user detection in CDMA systems, MIMO systems, and cognitive radio. The dominant wireless standards; including cellular, cordless and wireless LANs; are discussed.Topics featured include: wireless propagation channels, transceivers and signal processing, multiple access and advanced transceiver schemes, and standardised wireless systems.Combines mathematical descriptions with intuitive explanations of the physical facts, enabling readers to acquire a deep understanding of the subject.Includes new chapters on cognitive radio, cooperative communications and relaying, video coding, 3GPP Long Term Evolution, and WiMax; plus significant new sections on multi-user MIMO, 802.11n, and information theory.Companion website featuring: supplementary material on 'DECT', solutions manual and presentation slides for instructors, appendices, list of abbreviations and other useful resources.
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paper_title: MAC Essentials for Wireless Sensor Networks

paper_content:

The wireless medium being inherently broadcast in nature and hence prone to interferences requires highly optimized medium access control (MAC) protocols. This holds particularly true for wireless sensor networks (WSNs) consisting of a large amount of miniaturized battery-powered wireless networked sensors required to operate for years with no human intervention. There has hence been a growing interest on understanding and optimizing WSN MAC protocols in recent years, where the limited and constrained resources have driven research towards primarily reducing energy consumption of MAC functionalities. In this paper, we provide a comprehensive state-of-the-art study in which we thoroughly expose the prime focus of WSN MAC protocols, design guidelines that inspired these protocols, as well as drawbacks and shortcomings of the existing solutions and how existing and emerging technology will influence future solutions. In contrast to previous surveys that focused on classifying MAC protocols according to the technique being used, we provide a thematic taxonomy in which protocols are classified according to the problems dealt with. We also show that a key element in selecting a suitable solution for a particular situation is mainly driven by the statistical properties of the generated traffic.
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paper_title: Energy efficient routing protocols for Wireless Sensor Networks: A survey

paper_content:

This paper provides an up to date evaluation of routing protocols as well as a description of state of the art routing techniques for Wireless Sensor Networks (WSNs) that enhance network lifetime through efficient energy consumption methods. We study the tradeoffs between energy and communication overhead and highlight the advantages and disadvantages of each routing protocol with the purpose of discovering new research directions.
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paper_title: Energy-efficient MAC protocols for wireless body area networks: Survey

paper_content:

In this paper, we provide a comprehensive survey of recent energy-efficient medium access control (MAC) protocols for wireless body area networks (WBANs) and presents a comparison of the various approaches pursued. At the outset, we outline the crucial attributes for a good MAC. Several sources that contribute to the energy inefficiency are identified. Then, we investigate few MAC protocols devised for WBAN by emphasizing their salient features. As a conclusion, we put forward a number of open research challenges with regard to prospects of medium access techniques and other issues.
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paper_title: Modeling and Performance Analysis for Duty-Cycled MAC Protocols with Applications to S-MAC and X-MAC

paper_content:

Wireless sensor networks are often battery-powered, and hence extending the network lifetime is one of the primary concerns in the ubiquitous deployment of wireless sensor networks. One approach to efficiently utilize the limited energy supplies of the sensors is to have the medium access control (MAC) protocol duty-cycle the sensors, periodically putting the sensors to sleep and waking them up to reduce idle listening, which is energy intensive. Among duty-cycled MAC protocols, some protocols are synchronized so that nodes wake up at the same time in each cycle, and other protocols are asynchronous, where nodes have arbitrary offsets to start their cycles. For protocol designers, it is important to understand which type of duty-cycled MAC protocol should be chosen (synchronized or asynchronous), as well as what values should be assigned to the protocol parameters under a given network scenario in order to achieve a desirable performance for throughput, delay, or energy consumption. However, previous work to analyze the performance of different duty-cycled MAC protocols is either protocol-specific, or limited to one aspect of the performance metric. In this paper, we propose a Markov queuing model to analyze the throughput, delay, and energy consumption of both synchronized and asynchronous duty-cycled MAC protocols with applications to S-MAC and X-MAC. Our contributions include: 1) proposing a Markov queuing model to describe the queuing behavior of both synchronous and asynchronous duty-cycled nodes, 2) modeling the queue dynamics and the stationary probability of packet transmissions for S-MAC, a synchronized duty-cycled MAC protocol, to analyze its performance, 3) modeling the queue dynamics and the stationary probability of packet transmissions for X-MAC, an asynchronous duty-cycled MAC protocol, to analyze its performance, 4) providing comprehensive performance estimation and comparison for different duty-cycled MAC protocols, and 5) providing flexibility to tradeoff different performance metrics by optimizing the protocol parameters. Our model results are validated by comparing with NS-2 and Matlab simulations.
---
paper_title: LMAC: An Energy-Latency Trade-off MAC Protocol for Wireless Sensor Networks

paper_content:

This paper proposes LMAC (latency MAC) protocol for wireless sensor networks. We investigate the idle listening problem and try to avoid it by sacrificing latency. We examine the latency constraint in wireless sensor networks and study the tradeoff between extra latency and energy efficiency. In the process of trading latency for energy efficiency, there are many restrictions. Thus, we study and analyze these limitations and then try to achieve the best tradeoff between latency and energy-efficiency under these limitations. By increasing the arrival prediction accuracy of data packets, the simulation results show that LMAC indeed consumes less energy, especially under a loose latency constraint or a light traffic load in wireless sensor network environments.
---
paper_title: Adaptive time division multiple access-based medium access control protocol for energy conserving and data transmission in wireless sensor networks

paper_content:

Traditional time division multiple access (TDMA)-based medium access control (MAC) protocols for wireless sensor networks (WSNs), for example, low-energy adaptive clustering hierarchy (LEACH), allocate one time slot for each node within a cluster. For nodes that have no data to send, the radio module is still active. Such approaches drain the precious battery energy. In this study, the authors propose a novel TDMA-based MAC protocol to conserve energy and increase data transmission efficiency of sensors in a cluster-based WSN. In the proposed scheme, nodes that have no data to send can go into sleep mode for energy conserving. On the other hands, nodes that have more data to send can ask the cluster head to allocate more time slots for data transmission. Experiments show that the proposed MAC protocol can have better performance than traditional TDMA-based MAC protocols.
---
paper_title: An energy efficient and delay sensitive centralized MAC protocol for wireless sensor networks

paper_content:

Energy consumption is one of the most crucial design issues in wireless sensor networks since prolonging the network lifetime depends on the efficient management of sensing node energy resource. In this research study, a new TDMA based MAC protocol, which is not only energy aware but also delay sensitive, is introduced for wireless sensor networks. In the proposed MAC, to achieve energy conservation, sensing nodes employing the proposed MAC sleeps periodically to reduce duty cycle and minimize idle listening. In addition, to provide lower message delay, any time critical sensing node requests extra time slots form the central node when its queue size exceeds the upper threshold value. Unlike common wireless sensor network models with a multi-hop topology, the proposed WSN architecture has a centralized structure especially for energy efficiency and fulfillment of the delay requirement of time critical networking applications. The proposed MAC has been modeled and simulated using OPNET Modeler Software for performance evaluation. Simulation results of the WSN model employing the new MAC are also presented including comparisons with those of a WSN counterpart employing conventional IEEE 802.11 DCF MAC protocol. By varying the interarrival time between 1 and 8 s for 100 wireless sensing nodes, in the best case, as a consequence of the new scheduling algorithms developed 9448 times better end to end message delay result and 1.9 times lower energy consumption ratio have been obtained for WSN employing the proposed MAC when compared with the WSN model employing IEEE 802.11 DCF MAC.
---
paper_title: An Adaptive Energy-Efficient Medium Access Control Protocol for Wireless Sensor Networks

paper_content:

Since the duty cycle of S-MAC is fixed and longer, it will cause longer idle time and latency of data packets under light loads. To solve these problems we present a new MAC protocol in which the sleep/wakeup schedules of the sensor nodes are adaptively determined, sensor nodes may sleep frequently. And also it minimizes control-packet overhead. Simulation shows that the new MAC is of significant effective in lessening delay time and power saving.
---
paper_title: Application-driven, energy-efficient communication in wireless sensor networks

paper_content:

Several sensor network applications based on data diffusion and data management can determine the communication transfer rate between two sensors beforehand. In this framework, we consider the problem of energy efficient communication among nodes of a wireless sensor network and propose an application-driven approach that minimizes radio activity intervals and prolongs network lifetime. On the basis of possible communication delays we estimate packet arrival intervals at any intermediate hop of a fixed-rate data path. We study a generic strategy of radio activity minimization wherein each node maintains the radio switched on just in the expected packet arrival intervals and guarantees low communication latency. We define a probabilistic model that allows the evaluation of the packet loss probability that results from the reduced radio activity. The model can be used to optimally choose the radio activity intervals that achieve a certain probability of successful packet delivery for a specific radio activity strategy. Relying on the probabilistic model we also define a cost model that estimates the energy consumption of the proposed strategies, under specific settings. We propose three specific strategies and numerically evaluate the associated costs. We finally validate our work with a simulation made with TOSSIM (the Berkeley motes' simulator). The simulation results confirm the validity of the approach and the accuracy of the analytic models.
---
paper_title: Adaptive time division multiple access-based medium access control protocol for energy conserving and data transmission in wireless sensor networks

paper_content:

Traditional time division multiple access (TDMA)-based medium access control (MAC) protocols for wireless sensor networks (WSNs), for example, low-energy adaptive clustering hierarchy (LEACH), allocate one time slot for each node within a cluster. For nodes that have no data to send, the radio module is still active. Such approaches drain the precious battery energy. In this study, the authors propose a novel TDMA-based MAC protocol to conserve energy and increase data transmission efficiency of sensors in a cluster-based WSN. In the proposed scheme, nodes that have no data to send can go into sleep mode for energy conserving. On the other hands, nodes that have more data to send can ask the cluster head to allocate more time slots for data transmission. Experiments show that the proposed MAC protocol can have better performance than traditional TDMA-based MAC protocols.
---
paper_title: An energy efficient and delay sensitive centralized MAC protocol for wireless sensor networks

paper_content:

Energy consumption is one of the most crucial design issues in wireless sensor networks since prolonging the network lifetime depends on the efficient management of sensing node energy resource. In this research study, a new TDMA based MAC protocol, which is not only energy aware but also delay sensitive, is introduced for wireless sensor networks. In the proposed MAC, to achieve energy conservation, sensing nodes employing the proposed MAC sleeps periodically to reduce duty cycle and minimize idle listening. In addition, to provide lower message delay, any time critical sensing node requests extra time slots form the central node when its queue size exceeds the upper threshold value. Unlike common wireless sensor network models with a multi-hop topology, the proposed WSN architecture has a centralized structure especially for energy efficiency and fulfillment of the delay requirement of time critical networking applications. The proposed MAC has been modeled and simulated using OPNET Modeler Software for performance evaluation. Simulation results of the WSN model employing the new MAC are also presented including comparisons with those of a WSN counterpart employing conventional IEEE 802.11 DCF MAC protocol. By varying the interarrival time between 1 and 8 s for 100 wireless sensing nodes, in the best case, as a consequence of the new scheduling algorithms developed 9448 times better end to end message delay result and 1.9 times lower energy consumption ratio have been obtained for WSN employing the proposed MAC when compared with the WSN model employing IEEE 802.11 DCF MAC.
---
paper_title: Application-driven, energy-efficient communication in wireless sensor networks

paper_content:

Several sensor network applications based on data diffusion and data management can determine the communication transfer rate between two sensors beforehand. In this framework, we consider the problem of energy efficient communication among nodes of a wireless sensor network and propose an application-driven approach that minimizes radio activity intervals and prolongs network lifetime. On the basis of possible communication delays we estimate packet arrival intervals at any intermediate hop of a fixed-rate data path. We study a generic strategy of radio activity minimization wherein each node maintains the radio switched on just in the expected packet arrival intervals and guarantees low communication latency. We define a probabilistic model that allows the evaluation of the packet loss probability that results from the reduced radio activity. The model can be used to optimally choose the radio activity intervals that achieve a certain probability of successful packet delivery for a specific radio activity strategy. Relying on the probabilistic model we also define a cost model that estimates the energy consumption of the proposed strategies, under specific settings. We propose three specific strategies and numerically evaluate the associated costs. We finally validate our work with a simulation made with TOSSIM (the Berkeley motes' simulator). The simulation results confirm the validity of the approach and the accuracy of the analytic models.
---
paper_title: Adaptive Collision Avoidance through Implicit Acknowledgments in WSNs

paper_content:

The large number of nodes, typical of many sensor network deployments, and the well-known hidden terminal problem make collision avoidance an essential goal for the actual employment of WSN technology. Collision avoidance is traditionally dealt with at the MAC Layer and plenty of different solutions have been proposed, which however have encountered limited diffusion because of their incompatibility with commonly available devices.In this paper we propose an approach to collision avoidance which is designed to work over a standard MAC Layer, namely the IEEE 802.15.4 MAC, and is based on application-controlled delays of packet transmission times. The proposed scheme is simple, decentralized and scalable. We present two variants of the algorithm and we evaluate our work through simulations. Discussed results show that our scheme provides a considerable boost of performance in IEEE 802.15.4 tree-based networks, effectively addressing the hidden terminal problem and keeping radio utilization efficient.
---
paper_title: A New Contention Access Method for Collision Avoidance in Wireless Sensor Networks

paper_content:

In this paper, we present a new contention access method for scalable wireless sensor networks. In these networks, the traffic levels are often variants, particularly in monitoring applications. Sensors do not regularly have much data to send. However, when an event occurs, every sensor in a given area will send its alert to the access point simultaneously. Hence, this network suffers a huge number of communications at the same time. In fact, at an instant, only one transmission is permitted among interfering nodes. If there are more than two transmissions at the same time, there will be a collision. Therefore, this variant communication of wireless sensor networks leads to an increase in collision and energy consumption. Traditional wireless network uses an exponential back-off scheme to react to collision. However, this scheme is designed for traditional wireless networks and is not well adapted to wireless sensor networks. Our proposal uses a dynamical change of channel access probability which can reduce the number of contention times and collisions. Moreover, it can be applied in any existing MAC protocol of wireless sensor network.
---
paper_title: Energy minimization using nanoMAC protocols in multihop wireless sensor network

paper_content:

Sensor networks consist of large number of distributed nodes, which have ad hoc topology and high traffic rates. Since the traffic offered in the network is highly dynamic and sensor devices are battery operated, the medium access control (MAC) protocol designed for the network must be stable and should consume less energy. Conventional non-persistent carrier sense multiple access (CSMA) based MAC protocol is not suitable for wireless sensor network (WSN) because of higher probability of frame collisions and larger energy consumption at variable traffic rates. Hence this paper considers a carrier sense multiple access protocol with collision avoidance (CSMA/CA) called nanoMAC, which is more suitable for WSN to achieve high data and energy efficiency. Analysis of the nanoMAC protocol is carried out to evaluate the throughput, delay and energy consumption to maximize the lifetime of the multihop network. Simulation results show that using nanoMAC protocol for multihop forwarding is more energy efficient than single hop communication when the feasible transmission distance is out of the characteristic distance range.
---
paper_title: A Novel Asynchronous, Energy Efficient, Low Transmission Delay MAC Protocol for Wireless Sensor Networks

paper_content:

Wireless Sensor Networks use battery-operated computing and sensing devices. It is often impractical or even impossible to charge/replace the exhausted batteries of the nodes. Thus, energy consumption is the main concern in a wireless sensor network. Moreover, a critical event detected by the sensor network should be delivered to the user as soon as possible. Thus, for sensor networks, both energy efficiency and transmission latency are important parameters. In this paper, we propose a novel asynchronous, duty cycled, energy efficient, and low transmission delay for wireless sensor networks, which addresses all the sources of energy waste to make the medium access more energy efficient, while keeping transmission delay low.The currently available asynchronous contention-based MAC protocols require that proper strategies for sender and receiver nodes are provided to rendezvous. However, the proposed protocol does not rely on any rendezvous between sender and receiver. For evaluating the novel MAC protocol, we have simulated this protocol and two very efficient and established MAC protocols, RTS/CTS IEEE 802.11 and S-MAC. The simulation results indicate that the proposed protocol has very good performance. In addition, as the results show, the novel protocol provides a very suitable balance between energy efficiency and transmission delay.
---
paper_title: Energy Efficient Wireless Sensor MAC Protocol for Collision Avoidance

paper_content:

In sensor networks communication by broadcast method involves many hazards, especially collision. Several MAC layer protocols have been proposed to resolve the problem of collision namely ARBP, where the best achieved success rate is 90%. We hereby propose a MAC protocol which achieves a greater success rate (Success rate is defined as the percentage of delivered packets at the source reaching the destination successfully) by reducing the number of collisions, but by trading off the average propagation delay of transmission. Our proposed protocols are also shown to be more energy efficient in terms of energy dissipation per message delivery, compared to the currently existing protocol.
---
paper_title: AEEMAC: Adaptive energy efficient MAC protocol for wireless sensor networks

paper_content:

In this paper, we investigate the available energy-efficient Medium Access Control protocols for wireless sensor networks emphasizing on their energy saving methods and present a simple but effective energy efficient MAC protocol named AEEMAC (Adaptive Energy Efficient MAC protocol). Like SMAC, AEEMAC also employs a duty cycling to save energy by avoiding idle listening, but incorporates three additional optimizations to further improve energy efficiency at MAC layer. These optimizations are — (i) adaptive sleeping and reusing of channel, (ii) use of combined ‘SYNC-RTS’ control packet, and (iii) use of combined ‘ACK-RTS’ control packet in bidirectional and multihop data transmission. The energy efficiency of AEEMAC is demonstrated for single hop as well as multihop scenarios through a detailed simulation study in NS-2. Simulation results show the suitability of AEEMAC in extending network lifetime of WSNs as compared to SMAC.
---
paper_title: A New Contention Access Method for Collision Avoidance in Wireless Sensor Networks

paper_content:

In this paper, we present a new contention access method for scalable wireless sensor networks. In these networks, the traffic levels are often variants, particularly in monitoring applications. Sensors do not regularly have much data to send. However, when an event occurs, every sensor in a given area will send its alert to the access point simultaneously. Hence, this network suffers a huge number of communications at the same time. In fact, at an instant, only one transmission is permitted among interfering nodes. If there are more than two transmissions at the same time, there will be a collision. Therefore, this variant communication of wireless sensor networks leads to an increase in collision and energy consumption. Traditional wireless network uses an exponential back-off scheme to react to collision. However, this scheme is designed for traditional wireless networks and is not well adapted to wireless sensor networks. Our proposal uses a dynamical change of channel access probability which can reduce the number of contention times and collisions. Moreover, it can be applied in any existing MAC protocol of wireless sensor network.
---
paper_title: Energy minimization using nanoMAC protocols in multihop wireless sensor network

paper_content:

Sensor networks consist of large number of distributed nodes, which have ad hoc topology and high traffic rates. Since the traffic offered in the network is highly dynamic and sensor devices are battery operated, the medium access control (MAC) protocol designed for the network must be stable and should consume less energy. Conventional non-persistent carrier sense multiple access (CSMA) based MAC protocol is not suitable for wireless sensor network (WSN) because of higher probability of frame collisions and larger energy consumption at variable traffic rates. Hence this paper considers a carrier sense multiple access protocol with collision avoidance (CSMA/CA) called nanoMAC, which is more suitable for WSN to achieve high data and energy efficiency. Analysis of the nanoMAC protocol is carried out to evaluate the throughput, delay and energy consumption to maximize the lifetime of the multihop network. Simulation results show that using nanoMAC protocol for multihop forwarding is more energy efficient than single hop communication when the feasible transmission distance is out of the characteristic distance range.
---
paper_title: A Novel Asynchronous, Energy Efficient, Low Transmission Delay MAC Protocol for Wireless Sensor Networks

paper_content:

Wireless Sensor Networks use battery-operated computing and sensing devices. It is often impractical or even impossible to charge/replace the exhausted batteries of the nodes. Thus, energy consumption is the main concern in a wireless sensor network. Moreover, a critical event detected by the sensor network should be delivered to the user as soon as possible. Thus, for sensor networks, both energy efficiency and transmission latency are important parameters. In this paper, we propose a novel asynchronous, duty cycled, energy efficient, and low transmission delay for wireless sensor networks, which addresses all the sources of energy waste to make the medium access more energy efficient, while keeping transmission delay low.The currently available asynchronous contention-based MAC protocols require that proper strategies for sender and receiver nodes are provided to rendezvous. However, the proposed protocol does not rely on any rendezvous between sender and receiver. For evaluating the novel MAC protocol, we have simulated this protocol and two very efficient and established MAC protocols, RTS/CTS IEEE 802.11 and S-MAC. The simulation results indicate that the proposed protocol has very good performance. In addition, as the results show, the novel protocol provides a very suitable balance between energy efficiency and transmission delay.
---
paper_title: Energy Efficient Wireless Sensor MAC Protocol for Collision Avoidance

paper_content:

In sensor networks communication by broadcast method involves many hazards, especially collision. Several MAC layer protocols have been proposed to resolve the problem of collision namely ARBP, where the best achieved success rate is 90%. We hereby propose a MAC protocol which achieves a greater success rate (Success rate is defined as the percentage of delivered packets at the source reaching the destination successfully) by reducing the number of collisions, but by trading off the average propagation delay of transmission. Our proposed protocols are also shown to be more energy efficient in terms of energy dissipation per message delivery, compared to the currently existing protocol.
---
paper_title: AEEMAC: Adaptive energy efficient MAC protocol for wireless sensor networks

paper_content:

In this paper, we investigate the available energy-efficient Medium Access Control protocols for wireless sensor networks emphasizing on their energy saving methods and present a simple but effective energy efficient MAC protocol named AEEMAC (Adaptive Energy Efficient MAC protocol). Like SMAC, AEEMAC also employs a duty cycling to save energy by avoiding idle listening, but incorporates three additional optimizations to further improve energy efficiency at MAC layer. These optimizations are — (i) adaptive sleeping and reusing of channel, (ii) use of combined ‘SYNC-RTS’ control packet, and (iii) use of combined ‘ACK-RTS’ control packet in bidirectional and multihop data transmission. The energy efficiency of AEEMAC is demonstrated for single hop as well as multihop scenarios through a detailed simulation study in NS-2. Simulation results show the suitability of AEEMAC in extending network lifetime of WSNs as compared to SMAC.
---
paper_title: An Efficient TDMA Scheme with Dynamic Slot Assignment in Clustered Wireless Sensor Networks

paper_content:

In this paper, we present an efficient MAC layer scheme using Dynamic Slot Assignment (DSA) in TDMA-based MAC protocols for cluster-based wireless sensor networks. The DSA scheme is presented to analyze the energy efficiency and channel utilization in a bursty traffic environment under low traffic conditions with a large number of sensor nodes in a single cluster. The DSA scheme will allow the network to adapt to the changing traffic load. Based on the network activity, the connection is established between the cluster-head node and those sensor nodes which have data to send, and a TDMA slot is assigned to each of them dynamically. We present the complete system model and model the data traffic by a correlated stochastic process (i.e. Markov chain) for a network where the second and subsequent connection arrival rate is dependent on the first arrival rate. We numerically compare our DSA with a traditionally proposed static TDMA model, the BMA model, and a variant of the BMA model (EA-TDMA), and prove substantial improvement in the energy consumption and channel utilization in low activity sensor networks. Results show that the efficiency of the MAC protocol can be increased significantly using the presented model.
---
paper_title: A self-reorganizing slot allocation protocol for multi-cluster sensor networks

paper_content:

This paper presents a self-reorganizing slot allocation (SRSA) mechanism for TDMA based medium access control (MAC) in wireless sensor networks. With TDMA, a node can achieve significant energy savings by remaining active only during allocated slots for transmissions and receptions. In multi-cluster networks, it is often necessary for nodes to use either CDMA or FDMA for preventing interference across neighbor clusters. The goal of this paper is to provide an alternative design that can reduce inter-cluster TDMA interference without having to use spectrum expensive CDMA or FDMA. The primary contribution of this paper is to demonstrate that with adaptive slot allocation, it is possible to reduce such interference under low loading conditions, which is often the case for sensor networks with monitoring applications. The second contribution is to design a feedback based adaptive allocation reorganization protocol that can significantly reduce those interferences without relying on any global synchronization mechanisms. We present the design of SRSA and provide a simulation based characterization of the protocol in comparison with TDMA-over-CDMA, TDMA with random slot allocation and CSMA MAC protocols. The results indicate that with moderate cluster overlapping and low traffic, SRSA can significantly reduce inter-cluster TDMA interference while delivering TDMA-over-CDMA like energy efficiency, at the cost of higher delivery latency compared to TDMA-over-CDMA. Assuming its low complexity and narrow-band operation unlike TDMA-over-CDMA, SRSA can be an ideal sensor MAC protocol for applications that can tolerate relatively larger delivery latency but not frequent packet drops.
---
paper_title: An Efficient MAC Protocol with Correlated Connection Arrival and Variable Slot Assignment in Wireless Sensor Networks

paper_content:

We present a novel analytical framework to investigate the performance of activity based TDMA slot scheduling under varying traffic conditions in cluster-based wireless sensor networks. Dynamic TDMA Slot Scheduling (DTSS) scheme is presented to analyze the channel utilization and packet dropping probability in bursty network environment under low and high traffic conditions with a large number of sensor nodes in a single cluster. DTSS scheme will allow the network to adapt to the changing traffic load. Based on the network activity, the connection is established between the cluster-head node and those sensors nodes which have data to send, and requested number of TDMA slots is assigned to them dynamically. We have modeled the data traffic by a correlated stochastic process (i.e. Markov chain) for a network where the second and subsequent connection arrival rate is dependent on the first arrival rate. We numerically compared DTSS with traditionally proposed static TDMA model and proved substantial improvement in the bandwidth efficiency and decrease in connection blocking probability in low activity networks. The drawback of the proposed system is also investigated. Results show that the efficiency of the MAC protocol can be increased significantly using the proposed model with reasonably low packet dropping probability.
---
paper_title: An Efficient TDMA Scheme with Dynamic Slot Assignment in Clustered Wireless Sensor Networks

paper_content:

In this paper, we present an efficient MAC layer scheme using Dynamic Slot Assignment (DSA) in TDMA-based MAC protocols for cluster-based wireless sensor networks. The DSA scheme is presented to analyze the energy efficiency and channel utilization in a bursty traffic environment under low traffic conditions with a large number of sensor nodes in a single cluster. The DSA scheme will allow the network to adapt to the changing traffic load. Based on the network activity, the connection is established between the cluster-head node and those sensor nodes which have data to send, and a TDMA slot is assigned to each of them dynamically. We present the complete system model and model the data traffic by a correlated stochastic process (i.e. Markov chain) for a network where the second and subsequent connection arrival rate is dependent on the first arrival rate. We numerically compare our DSA with a traditionally proposed static TDMA model, the BMA model, and a variant of the BMA model (EA-TDMA), and prove substantial improvement in the energy consumption and channel utilization in low activity sensor networks. Results show that the efficiency of the MAC protocol can be increased significantly using the presented model.
---
paper_title: A self-reorganizing slot allocation protocol for multi-cluster sensor networks

paper_content:

This paper presents a self-reorganizing slot allocation (SRSA) mechanism for TDMA based medium access control (MAC) in wireless sensor networks. With TDMA, a node can achieve significant energy savings by remaining active only during allocated slots for transmissions and receptions. In multi-cluster networks, it is often necessary for nodes to use either CDMA or FDMA for preventing interference across neighbor clusters. The goal of this paper is to provide an alternative design that can reduce inter-cluster TDMA interference without having to use spectrum expensive CDMA or FDMA. The primary contribution of this paper is to demonstrate that with adaptive slot allocation, it is possible to reduce such interference under low loading conditions, which is often the case for sensor networks with monitoring applications. The second contribution is to design a feedback based adaptive allocation reorganization protocol that can significantly reduce those interferences without relying on any global synchronization mechanisms. We present the design of SRSA and provide a simulation based characterization of the protocol in comparison with TDMA-over-CDMA, TDMA with random slot allocation and CSMA MAC protocols. The results indicate that with moderate cluster overlapping and low traffic, SRSA can significantly reduce inter-cluster TDMA interference while delivering TDMA-over-CDMA like energy efficiency, at the cost of higher delivery latency compared to TDMA-over-CDMA. Assuming its low complexity and narrow-band operation unlike TDMA-over-CDMA, SRSA can be an ideal sensor MAC protocol for applications that can tolerate relatively larger delivery latency but not frequent packet drops.
---
paper_title: An Efficient MAC Protocol with Correlated Connection Arrival and Variable Slot Assignment in Wireless Sensor Networks

paper_content:

We present a novel analytical framework to investigate the performance of activity based TDMA slot scheduling under varying traffic conditions in cluster-based wireless sensor networks. Dynamic TDMA Slot Scheduling (DTSS) scheme is presented to analyze the channel utilization and packet dropping probability in bursty network environment under low and high traffic conditions with a large number of sensor nodes in a single cluster. DTSS scheme will allow the network to adapt to the changing traffic load. Based on the network activity, the connection is established between the cluster-head node and those sensors nodes which have data to send, and requested number of TDMA slots is assigned to them dynamically. We have modeled the data traffic by a correlated stochastic process (i.e. Markov chain) for a network where the second and subsequent connection arrival rate is dependent on the first arrival rate. We numerically compared DTSS with traditionally proposed static TDMA model and proved substantial improvement in the bandwidth efficiency and decrease in connection blocking probability in low activity networks. The drawback of the proposed system is also investigated. Results show that the efficiency of the MAC protocol can be increased significantly using the proposed model with reasonably low packet dropping probability.
---
paper_title: Z-MAC: a hybrid MAC for wireless sensor networks

paper_content:

This paper presents the design, implementation and performance evaluation of a hybrid MAC protocol, called Z-MAC, for wireless sensor networks that combines the strengths of TDMA and CSMA while offsetting their weaknesses. Like CSMA, Z-MAC achieves high channel utilization and low-latency under low contention and like TDMA, achieves high channel utilization under high contention and reduces collision among two-hop neighbors at a low cost. A distinctive feature of Z-MAC is that its performance is robust to synchronization errors, slot assignment failures and time-varying channel conditions; in the worst case, its performance always falls back to that of CSMA. Z-MAC is implemented in TinyOS.
---
paper_title: ER-MAC: A Hybrid MAC Protocol for Emergency Response Wireless Sensor Networks

paper_content:

This paper introduces ER-MAC, a hybrid MAC protocol for emergency response wireless sensor networks. ERMAC is designed as a hybrid of the TDMA and CSMA approaches, giving it the flexibility to adapt to traffic and topology changes. It adopts a TDMA approach to schedule collision-free slots. Nodes wake up for their scheduled slots, but otherwise switch into power-saving sleep mode. When an emergency occurs, nodes that participate in the emergency monitoring change their MAC behaviour by allowing contention in TDMA slots to achieve high delivery ratio and low latency. ER-MAC offers a synchronised and loose slot structure to allow nodes to join or leave the network. Simulations in ns-2 show that ERMAC outperforms Z-MAC with higher delivery ratio, lower latency, and lower energy consumption.
---
paper_title: An Efficient TDMA Scheme with Dynamic Slot Assignment in Clustered Wireless Sensor Networks

paper_content:

In this paper, we present an efficient MAC layer scheme using Dynamic Slot Assignment (DSA) in TDMA-based MAC protocols for cluster-based wireless sensor networks. The DSA scheme is presented to analyze the energy efficiency and channel utilization in a bursty traffic environment under low traffic conditions with a large number of sensor nodes in a single cluster. The DSA scheme will allow the network to adapt to the changing traffic load. Based on the network activity, the connection is established between the cluster-head node and those sensor nodes which have data to send, and a TDMA slot is assigned to each of them dynamically. We present the complete system model and model the data traffic by a correlated stochastic process (i.e. Markov chain) for a network where the second and subsequent connection arrival rate is dependent on the first arrival rate. We numerically compare our DSA with a traditionally proposed static TDMA model, the BMA model, and a variant of the BMA model (EA-TDMA), and prove substantial improvement in the energy consumption and channel utilization in low activity sensor networks. Results show that the efficiency of the MAC protocol can be increased significantly using the presented model.
---
paper_title: A bit-map-assisted energy-efficient MAC scheme for wireless sensor networks

paper_content:

The low-energy characteristics of wireless sensor networks (WSNs) pose a great design challenge for MAC protocol design. Recent studies have proposed different cluster-based MAC protocols. In this paper, we propose an intra-cluster communication bit-map-assisted (BMA) MAC protocol for large-scale cluster-based WSNs. BMA is intended for event-driven applications, where sensor nodes transmit data to the cluster head only if significant events are observed. In addition, we provide the energy and packet latency analytical models for BMA, conventional TDMA, and energy efficient TDMA (E-TDMA) when used as intra-cluster MAC schemes. Our results show that BMA is superior for the cases of low and medium traffic loads, relatively few sensor nodes per cluster, and relatively large data packet sizes. In addition, BMA performs better than the TDMA-based MAC schemes in terms of average packet latency.
---
paper_title: Queue-MAC: A queue-length aware hybrid CSMA/TDMA MAC protocol for providing dynamic adaptation to traffic and duty-cycle variation in wireless sensor networks

paper_content:

Existing low-power MAC protocols only provide low throughput because of the fixed low duty-cycle. This often leads to poor performance when dealing with time-constrained burst traffic. In this paper, we propose a new hybrid CSMA/TDMA MAC protocol, called Queue-MAC, that dynamically adapts the duty-cycle according to the current network traffic. The queue length of nodes is used as the network traffic indicator. When the traffic increases, the active CSMA period is accordingly extended by adding dynamic TDMA slots, allowing thus to efficiently handle burst traffic under real-time constraints. This protocol is implemented on the STM32W108 SOC chips and compared with both a fixed duty-cycle reference protocol and an optimized IEEE802.15.4 MAC protocol. Through extensive experimental measurements, we showed that our queue-length aware hybrid CSMA/TDMA MAC protocol largely outperforms the compared protocols. The proposed protocol can be easily implemented through slight adaptation of the IEEE802.15.4 standard. It presents an optimal bandwidth and energy allocation scheme according to the traffic to be carried. In fact, low-duty cycle, so low power consumption is preserved during light traffic load period, while high throughput is obtained during heavy burst load period.
---
paper_title: An Efficient MAC Protocol with Correlated Connection Arrival and Variable Slot Assignment in Wireless Sensor Networks

paper_content:

We present a novel analytical framework to investigate the performance of activity based TDMA slot scheduling under varying traffic conditions in cluster-based wireless sensor networks. Dynamic TDMA Slot Scheduling (DTSS) scheme is presented to analyze the channel utilization and packet dropping probability in bursty network environment under low and high traffic conditions with a large number of sensor nodes in a single cluster. DTSS scheme will allow the network to adapt to the changing traffic load. Based on the network activity, the connection is established between the cluster-head node and those sensors nodes which have data to send, and requested number of TDMA slots is assigned to them dynamically. We have modeled the data traffic by a correlated stochastic process (i.e. Markov chain) for a network where the second and subsequent connection arrival rate is dependent on the first arrival rate. We numerically compared DTSS with traditionally proposed static TDMA model and proved substantial improvement in the bandwidth efficiency and decrease in connection blocking probability in low activity networks. The drawback of the proposed system is also investigated. Results show that the efficiency of the MAC protocol can be increased significantly using the proposed model with reasonably low packet dropping probability.
---
paper_title: A Hybrid MAC Protocol for Wireless Sensor Network

paper_content:

Since it is very hard for cluster-based WSN(Wireless Sensor Network) to implement efficient and secure communication either with CSMA or TDMA. In view of the existing situation, a STC-MAC protocol has been put forward, which mingled with CSMA and TDMA and brought about better bottom-layer security. On the one hand, the wireless channel allocated by TDMA in intra-cluster nodes is able to cope with collision and crosstalk to achieve low latency. On the other hand, with the allocation of CSMA between cluster-head nodes, the channel can avoid multiple hops synchronization and enhance scalability. Furthermore, an early-warning algorithm was provided in this protocol for quickly recognizing attacks and reinforcing security. In addition, the J-Sim simulation platform, especially including a energy output port, has been extended. Through the simulation results, STC-MAC turns out to be better in energy-efficiency and anti-attack than 802.11 MAC.
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paper_title: Z-MAC: a hybrid MAC for wireless sensor networks

paper_content:

This paper presents the design, implementation and performance evaluation of a hybrid MAC protocol, called Z-MAC, for wireless sensor networks that combines the strengths of TDMA and CSMA while offsetting their weaknesses. Like CSMA, Z-MAC achieves high channel utilization and low-latency under low contention and like TDMA, achieves high channel utilization under high contention and reduces collision among two-hop neighbors at a low cost. A distinctive feature of Z-MAC is that its performance is robust to synchronization errors, slot assignment failures and time-varying channel conditions; in the worst case, its performance always falls back to that of CSMA. Z-MAC is implemented in TinyOS.
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paper_title: ER-MAC: A Hybrid MAC Protocol for Emergency Response Wireless Sensor Networks

paper_content:

This paper introduces ER-MAC, a hybrid MAC protocol for emergency response wireless sensor networks. ERMAC is designed as a hybrid of the TDMA and CSMA approaches, giving it the flexibility to adapt to traffic and topology changes. It adopts a TDMA approach to schedule collision-free slots. Nodes wake up for their scheduled slots, but otherwise switch into power-saving sleep mode. When an emergency occurs, nodes that participate in the emergency monitoring change their MAC behaviour by allowing contention in TDMA slots to achieve high delivery ratio and low latency. ER-MAC offers a synchronised and loose slot structure to allow nodes to join or leave the network. Simulations in ns-2 show that ERMAC outperforms Z-MAC with higher delivery ratio, lower latency, and lower energy consumption.
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paper_title: Queue-MAC: A queue-length aware hybrid CSMA/TDMA MAC protocol for providing dynamic adaptation to traffic and duty-cycle variation in wireless sensor networks

paper_content:

Existing low-power MAC protocols only provide low throughput because of the fixed low duty-cycle. This often leads to poor performance when dealing with time-constrained burst traffic. In this paper, we propose a new hybrid CSMA/TDMA MAC protocol, called Queue-MAC, that dynamically adapts the duty-cycle according to the current network traffic. The queue length of nodes is used as the network traffic indicator. When the traffic increases, the active CSMA period is accordingly extended by adding dynamic TDMA slots, allowing thus to efficiently handle burst traffic under real-time constraints. This protocol is implemented on the STM32W108 SOC chips and compared with both a fixed duty-cycle reference protocol and an optimized IEEE802.15.4 MAC protocol. Through extensive experimental measurements, we showed that our queue-length aware hybrid CSMA/TDMA MAC protocol largely outperforms the compared protocols. The proposed protocol can be easily implemented through slight adaptation of the IEEE802.15.4 standard. It presents an optimal bandwidth and energy allocation scheme according to the traffic to be carried. In fact, low-duty cycle, so low power consumption is preserved during light traffic load period, while high throughput is obtained during heavy burst load period.
---
paper_title: A Hybrid MAC Protocol for Wireless Sensor Network

paper_content:

Since it is very hard for cluster-based WSN(Wireless Sensor Network) to implement efficient and secure communication either with CSMA or TDMA. In view of the existing situation, a STC-MAC protocol has been put forward, which mingled with CSMA and TDMA and brought about better bottom-layer security. On the one hand, the wireless channel allocated by TDMA in intra-cluster nodes is able to cope with collision and crosstalk to achieve low latency. On the other hand, with the allocation of CSMA between cluster-head nodes, the channel can avoid multiple hops synchronization and enhance scalability. Furthermore, an early-warning algorithm was provided in this protocol for quickly recognizing attacks and reinforcing security. In addition, the J-Sim simulation platform, especially including a energy output port, has been extended. Through the simulation results, STC-MAC turns out to be better in energy-efficiency and anti-attack than 802.11 MAC.
---

Title: Energy Efficient MAC Protocols for Wireless Sensor Network: A Survey

Section 1: Introduction
Description 1: Introduce the concept of Wireless Sensor Networks (WSNs), the importance of energy efficiency in WSNs, and the purpose of the survey.

Section 2: Background
Description 2: Provide background information on WSNs, their components, and the importance of energy efficiency.

Section 3: Sources of energy inefficiency in WSN
Description 3: Identify and explain the various sources of energy inefficiency in WSNs such as sensing, routing, and radio communication.

Section 4: Radio Communications
Description 4: Discuss the role of radio communication in WSNs, its impact on energy consumption, and the importance of energy-efficient MAC protocols.

Section 5: MAC Protocols
Description 5: Introduce different MAC protocols and explain why conventional wireless network MAC protocols are not suitable for WSNs.

Section 6: Survey of Existing State-of-the-Art (SOTA)
Description 6: Review existing state-of-the-art energy-efficient MAC protocols for WSNs and highlight their strengths and weaknesses.

Section 7: Controlled Access Protocols
Description 7: Present and review Controlled Access (CA) protocols, discussing their mechanisms, benefits, and limitations.

Section 8: Random Access (RA) Protocols
Description 8: Present and review Random Access (RA) protocols, discussing their mechanisms, benefits, and limitations.

Section 9: Slotted Protocols (SP)
Description 9: Present and review Slotted Protocols (SP), discussing their mechanisms, benefits, and limitations.

Section 10: Hybrid Protocols (HP)
Description 10: Present and review Hybrid Protocols (HP), discussing their mechanisms, benefits, and limitations.

Section 11: Challenges
Description 11: Summarize the challenges identified from the survey in terms of energy-efficient MAC protocols for WSNs.

Section 12: Conclusions and Future Work
Description 12: Conclude the survey, summarizing the key findings and suggesting areas for future research to enhance energy efficiency in WSNs.