Energy-Efficient Boarder Node Medium Access Control Protocol for Wireless Sensor Networks

WSN은 센서 탐지에 의한 데이터 전송을 목적으로 사용하며 이러한 송신 이벤트의 데이터 전송량은 일반적으로 용량이 작다. 이러한 이유로 일반적인 WSN MAC 프로토콜은 에너지 효율을 높이기 위하여 듀티 사이클 방식을 적용하지만, 이는 WMSN 환경에서 요구되는 대용량 멀티미디어 데이터 전송에 적합하지 않다. 본 논문에서는 WMSN 요구를 만족시키기 위하여 MAC 계층에서의 새로운 대용량 데이터 전송 기법을 제안하며, 기존 WSN 환경의 경쟁기반 MAC 프로토콜에서 도입하는 듀티 사이클 기법과 공존하여 적용할 수 있도록 설계하였다. 또한, 제안하는 대용량 데이터 전송기법은 송신 버퍼의 상태와 채널 환경을 고려하여 사용 유무를 결정하도록 설계되었으며, 송수신 노드가 대용량 데이터 전송 시점에서 이웃 노드에게 간섭받지 않고 채널 점유를 보장받을 수 있도록 설계되었다. 본 논문은 제안 방식의 객관적 성능을 평가하기 위하여 기존 듀티 사이클 기법을 지속적으로 운영하는 MAC과 제안하는 대용량 전송 방식을 혼용하여 운영하는 MAC을 모두 실험하고 그 결과를 분석하였다. For transmitting sensed data, wireless sensor networks have been developed and researched for the improvement of energy efficiency, hence, many MAC protocols in WSN employ the duty cycle mechanism. Since the progressed development of the low power transceiver and processor let the high energy efficiency come true, the delivery of the multimedia data which occurs in area of sensor work should be needed to provide supplemental information. In this paper, we design a new scheme for massive transmission of large multimedia data where the duty cycle is used in contention based MAC protocol, for WMSN. The proposed scheme can be applied into the previous duty cycle mechanism because it provides two operation between normal operation and massive transmission operation. Measuring the buffer status of sender and the condition of current radio channel can be criteria for the decision of the above two operations. This paper shows the results of the experiment by performing the simulation. The target protocol of the experiment is X-MAC which is contention based MAC protocol for WSN. And two approaches, both X-MAC which operates only duty cycle and X-MAC which operates combined massive transmission scheme, are used for the comparative experiment.

Directional antennas have numerous advantages over traditional omnidirectional antennas, which include more spatial reuse, extended range, less interference, and less energy consumption. Directional antennas introduce deafness and new hidden terminal problems. Deafness may cause more collisions, and hidden terminal problems may result in more retransmissions, poor quality of service, more energy consumption, and less packet delivery ratio. Hence, it is important to design of an effective medium access protocol specifically for directional antennas in order to reap the benefits of directional antennas while managing deafness and hidden terminal problems, otherwise the challenges can adversely affect system performance. In wireless sensor networks, the sensors are battery powered with limited supply of energy. Therefore, energy efficient protocols and solutions are immensely important with the desired goal of extending the network lifetime longer than what is possible through the omnidirectional antennas. In this thesis, I have proposed an energy efficient scheduled directional medium access control protocol (DTRAMA) which is specially designed for the wireless sensor nodes which use directional antennas in wireless sensor networks. It is a traffic adaptive scheduled medium access protocol in which nodes create their transmission and sleep schedules on the basis of their traffic. Scheduled medium access for packet transmission is used to address the deafness and hidden terminal problems caused by the use of directional communication in contention based MAC protocols. Use of directional antenna reduces interference which indirectly improves packet delivery ratio by improving the signal to noise ratio and by reducing the packet error rate. DTRAMA is energy efficient: firstly because the nodes use directional data communication which requires lower node transmit power than the omnidirectional data communication for the same transmission range; and secondly, because the nodes schedule their sleep period to reduce idle listening and overhearing which improves energy efficiency. In DTRAMA, sleep schedule of the node is traffic adaptive which is essential to maximize the sleep period. The node, by using spatial reuse checks, reuses the wireless medium to the maximum extent to reap the spatial reuse benefits of the directional antenna. The nodes reduce their packet latency through spatial reuse. Through simulation and by using different topologies, I have compared the performance of DTRAMA with those of omnidirectional schedule MAC protocol (TRAMA) and contention based directional MAC protocol (DMAC), which clearly shows that DTRAMA outperforms TRAMA and DMAC in packet delivery ratio and outperforms TRAMA in terms of packet latency.

Directional antennas have numerous advantages over traditional omnidirectional antennas, which include more spatial reuse, extended range, less interference, and less energy consumption. Directional antennas introduce deafness and new hidden terminal problems. Deafness may cause more collisions, and hidden terminal problems may result in more retransmissions, poor quality of service, more energy consumption, and less packet delivery ratio. Hence, it is important to design of an effective medium access protocol specifically for directional antennas in order to reap the benefits of directional antennas while managing deafness and hidden terminal problems, otherwise the challenges can adversely affect system performance. In wireless sensor networks, the sensors are battery powered with limited supply of energy. Therefore, energy efficient protocols and solutions are immensely important with the desired goal of extending the network lifetime longer than what is possible through the omnidirectional antennas. In this thesis, I have proposed an energy efficient scheduled directional medium access control protocol (DTRAMA) which is specially designed for the wireless sensor nodes which use directional antennas in wireless sensor networks. It is a traffic adaptive scheduled medium access protocol in which nodes create their transmission and sleep schedules on the basis of their traffic. Scheduled medium access for packet transmission is used to address the deafness and hidden terminal problems caused by the use of directional communication in contention based MAC protocols. Use of directional antenna reduces interference which indirectly improves packet delivery ratio by improving the signal to noise ratio and by reducing the packet error rate. DTRAMA is energy efficient: firstly because the nodes use directional data communication which requires lower node transmit power than the omnidirectional data communication for the same transmission range; and secondly, because the nodes schedule their sleep period to reduce idle listening and overhearing which improves energy efficiency. In DTRAMA, sleep schedule of the node is traffic adaptive which is essential to maximize the sleep period. The node, by using spatial reuse checks, reuses the wireless medium to the maximum extent to reap the spatial reuse benefits of the directional antenna. The nodes reduce their packet latency through spatial reuse. Through simulation and by using different topologies, I have compared the performance of DTRAMA with those of omnidirectional schedule MAC protocol (TRAMA) and contention based directional MAC protocol (DMAC), which clearly shows that DTRAMA outperforms TRAMA and DMAC in packet delivery ratio and outperforms TRAMA in terms of packet latency.

Energy efficiency is of the utmost importance in wireless sensor networks. The family of Low-Power-Listening MAC protocols was proposed to reduce one form of energy dissipation-idle listening, a radio state for which the energy consumption cannot be neglected. Low-Power-Listening MAC protocols are characterized by a duty cycle: a node probes the channel every t_i {\rm s} of sleep. A low duty cycle favors receiving nodes because they may sleep for longer periods of time, but at the same time, contention may increase locally, thereby reducing the number of packets that can be sent. We propose two new approaches to control the duty cycle so that the target rate of transmitted packets is reached, while the consumed energy is minimized. The first approach, called asymmetric additive duty cycle control (AADCC), employs a linear increase/linear decrease in the t_i value based on the number of successfully received packets. This approach is easy to implement, but it cannot provide an ideal solution. The second approach, called dynamic duty cycle control (DDCC) utilizes control theory to strike a near-optimal balance between energy consumption and packet delivery successes. We generalize both approaches to multihop networks. Results show that both approaches can appropriately adjust t_i to the current network conditions, although the dynamic controller (DDCC) yields results closer to the ideal solution. Thus, the network can use an energy saving low duty cycle, while delivering up to four times more packets in a timely manner when the offered load increases.

Reservation-based and contention-based MAC protocols have their own advantages in data transmissions under mobile sensor networks. This paper presents a quantitative analysis of two types of MAC protocols in throughput, delay, and energy efficiency under various traffic loads environments using queueing theory. The analytical and simulation results show the design strategies of hybrid MAC protocols for mobile dynamic traffic scenarios.

This paper presents a MAC protocol which uses separate wakeup slots for each sensor node in sensor networks. Most MAC protocols proposed for sensor network are inefficient under heavy traffic loads, in particular in high density network topology because of frequent collisions and long sleep latency. In this paper, we suggest a MAC protocol in which each node has a different wakeup schedule in the same duty cycle, and it joins the competition only for its own short wakeup slot when the receiver is ready to receive its data. Simulation results indicate that our scheme can reduce energy consumption and minimize idle listening which increases the power efficiency.

Wireless sensor networks (WSNs) are one of the very active research area. They have many applications like military, health care, environmental monitoring and industrial monitoring. The sensor nodes have limited energy source. Since in many cases the nodes are deployed in unreachable areas, hence recharging or replacing the battery of the sensor nodes is not an option. Therefore, one must employ techniques to conserve the energy by reducing the energy consumption by the nodes. In this paper, we discuss about the different energy saving schemes investigated by different research community in WSNs to reduce the energy consumption of the nodes and thereby improving the lifetime of the overall network. Energy saving protocols such as duty cycle, energy efficient routing, energy efficient medium access control (MAC), data aggregation, cross layer design and error control code (ECC) are discussed. Sleep/wake up method is adopted by the duty cycle approach to reduce the active time of the nodes and conserve their energy. The routing and MAC protocols use suitable energy efficient algorithms for saving energy. The data aggregation aims to save energy by reducing the number of transmissions. On the other side, cross layer approach looks for a cross layer optimization solution to improve the energy efficiency of the network. ECC reduces energy consumption by virtue of coding gain it offers which allows lower signal-to-noise ratio (SNR) to achieve the same bit error rate (BER) as an uncoded system. Some techniques such as use of directional antennas, topology control and transmission power control which have been widely investigated for other ad-hoc networks for energy conservation are also discussed in brief in this paper.

In this paper, we propose a detailed energy survey of the physical, data link, and network layer by analytical techniques. We also show the impact of regular sleep periods on node energy consumption and present a comparison analysis of single-hop vs. multi-hop communications in the energy realm. A detailed energy expenditure analysis of not only the physical layer but also the link and network layer provides a basis for developing new energy efficient wireless sensor networks. Regular, coordinated sleeping extends the lifetime of sensor nodes, but systems can only benefit from sleeping in terms of transmitted packets if the data arrival rate to the system is low. Energy efficiency is the driving motivation for it can be considered the most important factor for wireless sensor networks because of the power constraints set by battery operation. Radio solutions in the lower ISM bands are attractive because of their relatively easy implementation and low power consumption. However, the data rates of these commercial radios are also relatively low, limiting transmittable frame sizes to a few tens of octets along with strict duty cycle requirements. From the analysis we extract key parameters of selected MAC protocols and show that some traditional mechanisms, such as binary exponential backoff, have some inherent problems. We also argue that single-hop communications has up todo% lower energy consumption than multi-hop forwarding within the feasible transmission distances of an ISM radio. Index Terms-Energy efficiency, Wireless sensor net- works, Medium access control (MAC) protocols, multi-hop communications a duty cycIe (Z), (3), which is normally 10% for the 434MHz band and 1% for the 868MHz band. The duty cycle is defined as the ratio, expressed as a percentage, of the maximum transmitter on-time, relative to a one hour period. When a sensor network is expected to work continuously, this duty cycle has to be taken into account and it can affect the energy efficiency of a network. In this paper we perform cross-layer analysis by pre- senting topology, medium access control (MAC) and ra- dio transceiver energy consumption models that work in unison. The hear topology model represents a common network after network layer route discovery has been accomplished. We use an energy consumption model for the transmission and reception of MAC frames originally presented in (4), develop a coordinated sleep group energy consumption model, and analytically investigate the effect of sleep on sensor networks using three MAC protocols. From the analysis we show that although in an ideal scenario multi-hop communications perform better than single-hop communications, realistic energy models and especially the MAC protocol design have a significant impact. We propose a multi-group sleep model for our nanoMAC protocol, and show that reg- ular sleep periods have a significant, energy reducing impact on node energy consumption with low traf!fic rates. The radio transceiver energy model takes into account several important radio parameters and we use the RFM TRlOOO and RFM radio designers guide (5) for realistic transceiver parameters. The main metric used is absolute energy, consumption per useful transmitted bit. This means only the MAC or thc network protocol data unit (PDU) will be considered and all the other communicated bits, headers, control frames, preambles, etc. are considered as overhead. The rest of the paper is organized as follows. Some related work is discussed in Section IT and in Section 111 we look at the radio propagation energy model. Section TV presents the network topology and energy

Wireless sensor networks are used in many environmental monitoring applications (e.g., to monitor forest fires or volcanoes). In such applications, sensor nodes have a limited quantity of energy, but must operate for years without having their batteries changed. The main mechanism used to allow nodes to save energy is to sequence periods of activity and inactivity. However, the design of MAC and routing protocols for applications with low duty-cycle is still a challenge. In this paper, we propose an efficient flooding-based protocol combined with an unsynchronized MAC protocol operating at very low duty-cycle (≤ 1%) called E-ADCR (Energy-efficient Asynchronous low Duty-Cycle Routing protocol). Although flooding-based routing protocols are usually very simple to implement, they are often costly in terms of bandwidth, due to the large number of data copies. Our flooding-based routing protocol has the following features: (i) it benefits from rare common activities to reduce the amount of data copies generated by the flooding mechanism, (ii) it guarantees the reception of frames by a limited number of receivers by sending frames multiple times during the active period, and (iii) it uses a queue management policy to ensure that frames do not stay to long in queues. With these features and the strong cross-layer design with the MAC protocol, our protocol is able to achieve good performance with this very low duty-cycle.

Energy efficiency of the MAC protocol is a key design factor for wireless sensor networks (WSNs). Due to the importance of the problem, a number of energy efficient MAC protocols have been developed for WSNs. Preamble-sampling based MAC protocols (e.g., B-MAC and X-MAC) have overheads due to their preambles, and are inefficient at large wakeup intervals. SCP-MAC, a very energy efficient scheduling MAC protocol, minimizes the preamble by combining preamble sampling and scheduling techniques; however, it does not prevent energy loss due to overhearing; in addition, due to its synchronization procedure, it results in increased contention and delay. In this paper, we present an energy efficient MAC protocol for WSNs that avoids overhearing and reduces contention and delay by asynchronously scheduling the wakeup time of neighboring nodes. To validate our design and analysis, we implement the proposed scheme on the MicaZ platform. Experimental results show that AS-MAC considerably reduces energy consumption, packet loss and delay when compared with SCP-MAC.

Wireless Sensor Network (WSN) performance is improved with duty cycled Medium Access Control (MAC). However, many MAC variants still suffer from the problems related to idle listening and overhearing. Thus they are short of optimal energy efficiency which is one of the crucial aspect in WSN for increasing lifetime of nodes. It is observed from the literature that Wake-up Radio (WuR) systems can significantly reduce the problems aforementioned. WuRcan be used to optimize performance as it switches off node’s MCU (Micro Controller Unit) and also the main radio transceiver until a low-power receiver is triggered by a specific wireless transmission. Most of the existing WuR studies are either theoretical in nature or depended on custom-built simulators. In this paper we proposed a framework based on WuR for better performance and reduce energy consumption. It throws light into energy and delay tradeoffs and the empirical results with NS2 simulations revealed the utility of the proposed framework.

Data transfer within severe time constraints is crucial for wireless sensor networks used in mission-critical applications, such as industrial control and disaster monitoring. In such applications, exceeding time constraints and facing limitations in longevity can pose threats to human life. The primary option for powering wireless sensor networks is to utilize ambient energy sources like solar energy, thermal energy, etc., which are abundant in nature The lifetime and latency of these networks depend on a well-implemented duty cycle-based MAC protocol, and maximizing the duty cycle is achieved through efficient utilization of harvested and residual energy. Since harvested energy is inherently unpredictable, appropriate forecasting techniques are required. In this study, a prediction-based Energy Harvested MAC protocol (FPEH-MAC) based on the Facebook Prophet library is proposed to maximize the predicted duty cycle of the MAC protocol by forecasting harvested and residual energy. Additionally, this MAC protocol demonstrates an increase in residual energy and duty cycle, ensuring an extended lifecycle for the wireless sensor network. The suggested protocol was evaluated for latency, throughput, percentage increase in residual energy, and packet delivery ratio using OMNET, INET, Python, and MATLAB. The results of the analysis indicate that the proposed technique increases residual energy by 1.2%, enhances throughput by 33.33%, and reduces latency by 9.6% when compared to previous work.

Energy efficiency of MAC protocols in low data rate wireless multimedia sensor networks: A comparative study

Sensor nodes are small and low-cost portable devices that are connected wirelessly to form a wireless sensor network. Sensor nodes are typically powered by a chemical battery source that has a load-dependent finite lifetime. Most applications require wireless sensor networks to operate reliably for an extended period of time beginning with their deployment. To ensure both the longevity of a wireless sensor network via power management techniques and development of a self-powered sensor node, it is important to understand a sensor node’s operational energy consumption. It is well understood that wireless sensor network lifetime has a strong functional dependence on sensor node lifetime. This paper presents the development of a stochastic model to capture the expected energy consumption of a schedule-driven sensor node per cycle of operation by utilizing renewal theory, random stopping criteria, and Wald’s inequality. The model captures the expected energy consumed due to generic operation of a schedule-driven sensor node when an external event occurs (i.e., node level activities) and energy consumed due to carrier sense multiple access/collision avoidance medium access control protocol (i.e., retransmission attempts, channel listening, and other network level activities). The stochastic energy model is used to compute the expected lifetime and cycle lifetime of the sensor node. This paper also computes the deterministic energy bounds corresponding to the minimum and maximum energy consumption of a sensor node per cycle of operation. Analytical and numerical model validations are performed and presented.

Radio frequency energy transfer (RET) has been proposed as a promising solution to power sensor nodes in wireless sensor networks (WSNs). However, RET has a significant drawback to be directly applied to WSNs, i.e., unfairness in the achieved throughput among sensor nodes due to the difference of their energy harvesting rates that strongly depend on the distance between the energy emitting node and the energy harvesting nodes. The unfairness problem should be properly taken into account to mitigate the drawback caused from the features of RET. To resolve this issue, in this paper, we propose a medium access control (MAC) protocol for WSNs based on RET with two distinguishing features: energy adaptive (EA) duty cycle management that adaptively manages the duty cycle of sensor nodes according to their energy harvesting rates and EA contention algorithm that adaptively manages contentions among sensor nodes considering fairness. Through analysis and simulation, we show that our MAC protocol works well under the RET environment. Finally, to show the feasibility of WSNs with RET, we test our MAC protocol with a prototype system in a real environment.