Different Energy Saving Schemes in Wireless Sensor Networks: A Survey

Wireless Sensor Networks (WSNs) have been widely recognized as a promising solution for enhancing various aspects of electric power grid and realizing the vision of smart grid. However, energy crisis and challenging wireless environment in smart grid create a number of challenges for WSNs, as a result of which energy efficiency become critically important. On the other hand, cognitive radio (CR) technology is expected to play a vital role in smart grid networks. Cognitive Sensor Networks (CSNs) can effectively address some unique challenges of WSNs in smart grid. In this paper, we aim to design an energy efficient Medium Access Control (MAC) protocol for CSNs. In this regard, we propose ECR-MAC, which is an energy-efficient receiver-based MAC protocol for CSNs. ECR-MAC uses a energy-efficiency based auction mechanism and preamble sampling techniques for providing high energy efficiency and reliability. In addition, ECR-MAC explicitly accounts for the peculiarities of a CR environment. Analytical and simulation results demonstrate the effectiveness of ECR-MAC as a viable solution for CSNs.

Design of energy efficient medium access control (MAC) protocol for wireless sensor network (WSN) containing mobile nodes is a challenging task. Majority of the MAC protocols for wireless sensor networks assume static sensor nodes, which results in poor performance of such protocols in a network containing mobile nodes. In this paper we propose a MAC protocol which is energy efficient as well as suitable for a WSN containing mobile nodes. The proposed protocol is based on both TDMA and CSMA. It adjusts the frame size to adapt to the changes in mobility and traffic conditions. The performance of the proposed protocol has been compared with LEACH-C protocol. It outperforms LEACH-C in terms of average energy consumption, packet delivery ratio and network life time.

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 one of the important critical metrics during protocol design in Wireless Sensor Networks (WSNs). Existing Medium Access Control (MAC) protocols do not take the initial node power into consideration, which may result in unfair power consumption, especially for low-power nodes. This paper presents an energy-efficient dual-layer MAC protocol with adaptive layer duration for WSNs. The suggested MAC protocol aims to minimize the energy consumption for low-power nodes. Performance evaluation is conducted to compare the proposed MAC protocol with both Sensor-MAC (S-MAC) and Multi-Layer MAC (ML-MAC) using computer simulations. The simulation results show that the proposed MAC protocol saves energy more than both S-MAC and ML-MAC. The proposed protocol saves 66.2% and 34.1% of the energy compared to S-MAC and ML-MAC, respectively.

Energy efficiency is of utmost importance for wireless sensor networks deployed without any possibility of battery replenishments. Thus, design of energy efficient algorithms and protocols must consider resource constraints while maintaining the desired level of QoS. In this paper, we present EE-MAC, an Energy Efficient medium access control (MAC) protocol for distributed wireless sensor networks. EE-MAC achieves a low-duty-cycle and hence low energy consumption through optimized sleep intervals while transitioning between sleep and active states. We consider a weighted linear combination of delay and energy saving as the performance metrics and through extensive simulations, we observe reduced energy consumption at the cost of increased delay. EE-MAC also improves the delay performance for fixed number of nodes compared to S-MAC.

The massive growth in modern wireless technologies and devices has resulted in increase in spectrum demands and energy consumption of wireless sensor network (WSN). To overcome the spectral scarcity and to meet the energy requirements, a cognitive radio enabled WSN with an energy efficient medium access control protocol is required. However, existing approaches utilize either reactive sense and avoid approach or proactive spectrum access to reconfigure spectrum usage based on observations. In this paper, a team-based hybrid sensing method is proposed for cognitive radio sensor networks (CRSNs), which combines both reactive sensing and proactive sensing in a team based approach. Here, the sensor nodes are grouped into teams based on the detection probability of each primary user (PU) channels and each team senses a PU channel. To avoid sensing overheads and to limit energy consumption, a node with best detection probability $$(P_d)$$ called sensing representative node (SRN) is involved in reactive sensing. Dynamic channel allocation to the secondary users (SUs) with significantly increased throughput and reduced energy consumption are achieved by using proactive sensing. Proactive sensing predicts the primary user (PU) occupancy using SRNs and allows the SU transmission without any hindrance. Both simulation and software defined radio based hardware results show that, the proposed Hybrid Sensing improves the energy efficiency of CRSNs by $$11\%$$ over the existing sensing methods without degrading its sensing accuracy.

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, emerged as a promising technology, offering unique benefits and supporting diverse applications, in terms of sensing. The challenging issue in these networks is optimal utilization of energy of its node, which maximizes its lifetime. In this proposed algorithm, energy efficient strategies are focused to optimize the energy consumption of the node. The cross layer approach provides a generic solution to increase the performance and energy efficiency of the wireless sensor networks. The different techniques in energy efficient strategies are energy efficient routing, scheduling the node's sleeping state and reducing the volume of information transferred. Special protocols are proposed for each technique. Multi path routes with multiHop of the data transmission to the destination node with less node failures. We show that extensive simulation is done by shortest path flat routing technique using Network simulator2 and Java. The best energy efficiency will be obtained by combining and following all these techniques. Using an active node set the node participating in several sets may improve network lifetime. (5 pages)

Medium Access Control (MAC) protocol is one of the key network protocols that ensure Wireless Sensor Networks (WSNs) maintain high performance during communication. MAC protocol design plays an important role in improving the performances of the whole network. First, Wireless Passive Sensor Networks (WPSNs) and MAC protocols are introduced in this paper. Second, some existing MAC protocols are introduced. Sensor MAC (S-MAC) protocol is analyzed and existing improved backoff algorithms are introduced. A new MAC protocol called Improved Sensor MAC (IS-MAC) is then proposed to solve the problem that the contention window (CW) during carrier sense is fixed in S-MAC protocol. IS-MAC protocol is able to adjust CW in terms of network load, so energy consumption can be decreased. Finally, according to the simulation results on NS2, the proposed protocol has better performance in terms of throughput and energy consumption.

Use of aerial platforms for energy efficient medium access control in wireless sensor networks

New and diverse applications for Wireless Sensor Networks (WSNs) have led to new challenges. Cross-layer approaches have proven to be the most efficient optimization techniques for these problems, since they are able to take the behavior of the protocols at each layer into consideration to overcome the constraints for WSNs. Thus, this chapter focuses on identifying the core problems of WSNs and collects available cross layer solutions for them that have been proposed. The literature on cross-layer protocols, protocol improvements, and design methodologies for WSNs are reviewed, and a taxonomy is proposed in order to provide insights on the identification of cross-layer design in WSNs. The open issues are discussed in detail for future research, and precautionary guidelines for cross layer design to WSNs are indicated.

In wireless sensor networks, in order to satisfy the requirement of long working time of energy-limited nodes, we need to design an energy-efficient and lifetime-extended medium access control (MAC) protocol. In this paper, a node cooperation mechanism that one or multiple nodes with higher channel gain and sufficient residual energy help a sender relay its data packets to its recipient is employed to achieve this objective. We first propose a transmission power optimization algorithm to prolong network lifetime by optimizing the transmission powers of the sender and its cooperative nodes to maximize their minimum residual energy after their data packet transmissions. Based on it, we propose a corresponding power-optimized cooperative MAC protocol. A cooperative node contention mechanism is designed to ensure that the sender can effectively select a group of cooperative nodes with the lowest energy consumption and the best channel quality for cooperative transmissions, thus further improving the energy efficiency. Simulation results show that compared to typical MAC protocol with direct transmissions and energy-efficient cooperative MAC protocol, the proposed cooperative MAC protocol can efficiently improve the energy efficiency and extend the network lifetime.

Energy efficiency is a primary consideration in a wireless sensor network (WSN). This is also a major parameter when designing a medium access control (MAC) protocol for WSNs. Hierarchical clustering structure is regarded suitable for WSNs due to its good performance in energy conservation. In this work, an adequately flexible mechanism for clustering WSNs is designed, in which some creative or promotional metrics are utilized, such as cluster head selection algorithm, cluster optional reconstruction, interested data transmission, multiple path routing protocol. All these strategies were cooperated to maximize energy saving of whole system. An appropriate MAC protocol for this mechanism is proposed, by flexibly switching the status of diverse sensor nodes in different strategies. The simulation results show that the proposed MAC protocol is suitable for clustering WSNs and performs well in aspects of energy efficiency, flexibility and scalability.

SOHCL-RDT: A self-organized hybrid cross-layer design for reliable data transmission in wireless network