Energy-efficient Relay Selection Research Articles

An Energy-Efficient Learning Automata and Cluster-Based Routing Algorithm for Wireless Sensor Networks

Wireless sensor networks (WSNs), which may be used for a broad variety of applications, have recently emerged as a prominent data collection paradigm. The fundamental concerns in wireless sensor networks are the efficient use of energy and the reliable delivery of data, both of which are largely determined by the rate at which packets are dropped. When developing an energy-efficient routing protocol, one of the most important steps is selecting a node to act as a successor node in a routing path. The application of learning automata theory to guide the routing decisions made by the sensors in a WSN has recently been the subject of research in the field of WSNs, where it has been shown to have several advantages. In this paper, a learning automata-based PSO relay selection scheme for energyefficient relay selection and reliable data delivery is proposed. The network is clustered using the LEACH protocol. The random number in the traditional LEACH protocol will be stabilized with the sensor node energy level for CH stability. Every sensor node in the network estimates the best possible routes to the sink node using the PSO algorithm. Instead of retransmissions, here we introduce learning automata for successor node selection during packet loss. The proposed learning automata calculate the next node’s selection probability in a routing path using multi-objective parameters like communication cost, residual energy, distance from BS, buffer size, and previous selection probability. Performance evaluation clearly showed that the proposed approach decreases energy usage, transmission delays, and data transfers while extending network lifetime. According to the experimental results, the proposed scheme can improve energy efficiency by 21.68%, delay by 31%, PDR by 87%, routing overhead by 0.5%, and throughput by 18.76% as compared to existing techniques like O-LEACH (Optimized Low Energy Adaptive Clustering Hierarchy Protocol) and EEPC (enhanced energy proficient clustering).

A modified energy efficient relay selection for cognitive radio sensor networks

A modified energy efficient relay selection for cognitive radio sensor networks

A sleep scheduling based cooperative data transmission for wireless sensor network

ABSTRACT Wireless sensor network is the network of tiny size of sensor nodes. These sensor nodes have sensing capability and transmit the sensed information to sink node. If the energy of sensor nodes is not utilised properly, it results in performance degradation of the network. Sleep scheduling approach and cooperative communication techniques can be employed to enhance the network performance. Cooperative communication follows the relay-based transmission. The nodes turn its radio sleep and awake in sleep scheduling approaches. This paper considers the merits of both techniques and proposes the sleep scheduling-based cooperative data transmission approach for WSN. In this approach, optimal number of virtual cluster heads are calculated by the sink node according to the number of nodes and area of interest. The real cluster head is decided based on the distance and energy of the sensor nodes from the virtual cluster head. The node is paired with each other and follows the sleep scheduling approach. Further, the energy-efficient relay selection and data transmission according to cooperative technique improves the network performance. The simulation analysis shows that the proposed routing protocol outperforms the related existing routing protocols.

Energy and spectral efficient relay selection and resource allocation in mobile multi‐hop device to device communications

Energy and spectral efficient relay selection and resource allocation in mobile multi‐hop device to device communications

Energy-efficient relay selection and power allocation for multi-source multicast network-coded D2D communications

Device-to-device (D2D) communication improves spectrum efficiency (SE) and increases system capacity. Heterogeneous networks comprise macrocell and several small cells, such as picocells and femtocells, where femtocells are more efficient. In cooperative communications, one or several additional nodes help to send data from source to destination to improve the quality of service (QoS). Network coding (NC) in cooperative networks can extend data rate and coverage area of D2D communication. The purpose of this article is to minimize power consumption of transmitting nodes during network-coded cooperative D2D transmission to reduce the interference on co-channel transmissions. In this study, we consider cooperative multicast D2D communication with NC, where femtocell base stations (FBSs) are used as relay. We propose a method based on energy efficiency (EE) maximization for relay selection and power allocation for multi-source network-coded cooperative D2D communication in heterogeneous cellular networks. We present a solution to the proposed method and evaluate its performance. The results show that the introduced method significantly improves the SE and EE compared to the coordinated multi-point (CoMP) transmission, multi-source direct D2D communication (D-D2D), and other works.

Energy-Efficient Relay-Selection-Based Dynamic Routing Algorithm for IoT-Oriented Software-Defined WSNs

In this article, a dynamic routing algorithm based on energy-efficient relay selection (RS), referred to as DRA-EERS, is proposed to adapt to the higher dynamics in time-varying software-defined wireless sensor networks (SDWSNs) for the Internet-of-Things (IoT) applications. First, the time-varying features of SDWSNs are investigated from which the state-transition probability (STP) of the node is calculated based on a Markov chain. Second, a dynamic link weight is designed for DRA-EERS by incorporating both the link reward and the link cost, where the link reward is related to the link energy efficiency (EE) and the node STP, while the link cost is affected by the locations of nodes. Moreover, one adjustable coefficient is used to balance the link reward and the link cost. Finally, the energy-efficient routing problem can be formulated as an optimization problem, and DRA-EERS is performed to find the best relay according to the energy-efficient RS criteria derived from the designed link weight. The simulation results demonstrate that the path EE obtained by DRA-EERS through an available coefficient adjustment outperforms that by Dijkstra’s shortest path algorithm. Again, a tradeoff between the EE and the throughput can be achieved by adjusting the coefficient of the link weight, i.e., increasing the impact of the link reward to improve the EE, and otherwise, to improve the throughput.

Energy Efficient Relay Node Selection in WSN Using MPEGASIS Protocol

WSN comprises a large number of sensor nodes which used to sense the physical information and send collected data to the base station (BS) or sink node. These sensor nodes are powered with a battery and replacing a battery is an intricate task. These nodes are sometimes placed in the environment where humans cannot reach. Due to insufficient battery energy, need to make an energy efficient relay selection routing method which reduces the energy consumption of the sensor nodes and increases the longevity of the sensor network. Present work proposes an extension of PEGASIS routing method named as MPEGASIS which uses a clustering mechanism and a chain formation used in PEGASIS protocol to send the sensed data to the BS or sink node by consuming less energy compared to the PEGASIS protocol. We perform a comparative study between PEGASIS and MPEGASIS routing protocol. The simulation is performed with different node densities, i.e. 20, 40, 60, 80, 100 nodes. The network comparison metrics are Residual Energy, Throughput, and Packet Delivery Ratio.

Impact of Optimal Hop Distance on the Network Lifetime for Wireless Sensor Networks With QoS Requirements

In this letter, the impact of the optimal hop distance (OHD) on the network lifetime (NL) is analyzed in wireless sensor networks with the consideration of link quality of service (QoS) requirements. OHD is defined as the distance between the node and its next-hop’s optimal relay position (ORP) to the destination node, where the ORP determines the performance of the energy-efficient relay. If OHD equals the characteristic distance (CD) of the path, the minimum-energy path for a given node pair can be achieved. Moreover, the link rate also influences the NL. Hence, considering an expected link outage probability, the minimum link rate, which is related to OHD, and its corresponding expected estimation of the average link transmit power of the node are calculated. Finally, an algorithm for joint energy-efficient relay selection and link-rate allocation based on OHD selection is proposed to extend the NL. Simulation results show that the NL can be extended when OHD is less than CD.

SERS: Social-Aware Energy-Efficient Relay Selection in D2D Communications

The explosion of mobile applications and phenomenal adoption of mobile connectivity by end users have generated increasing amounts of mobile data traffic. Recognizing the need of increasing network capacity, cooperative device-to-device (D2D) communications and efficient power allocation have been proposed to address the imperative problem. Existing works mainly focus on relay selection and power control at physical layer. The social connections between mobile users, however, are omitted in consideration of improving the cooperative D2D communication quality. Leveraging social trust, we propose an innovative social-aware energy-efficient relay selection (SERS) mechanism that considers the hidden social ties among mobile users to ensure that more users are willing to participate in the cooperative communications. The proposed SERS takes both social and physical constraints into account to determine the best choice of relay devices. In SERS, we further develop an optimization problem based on game theory, aiming at reducing energy consumption and interference. In the game, social distance is treated as a penalty coefficient and performs distributed control of the transmission power for D2D communications. Simulations based on real-world social network data traces show that SERS achieves a significant performance gain, compared with other relay selection approaches.

Energy Efficient Relay Selection Scheme for Cooperative Transmission Aided Rateless Codes in Wireless Sensor Networks

Wireless sensor networks(WSNs) require energy efficient communication protocols to minimize the energy consumption and balance energy to extend the lifetime of network. This paper proposed an energy efficient relay selection scheme for cooperative transmission aided rateless codes in WSNs over Rayleigh fading channels. Cooperative transmission and rateless codes are applied to guaranty reliability. The residual energy and channel conditions are considered to select the optimal relay as cooperative relay. The simulation results show that the energy consumption is balanced and the network lifetime is extended, compared with some previous transmission schemes.

EE‐RS and PA for untrusted relay network at high signal‐to‐noise ratio regime

In this study, the authors investigate the energy-efficient (EE) relay selection (RS) and power allocation (PA) in a cooperative secured system. Their scenario includes a multiple-antenna source, a multiple-antenna destination and multiple amplify-and-forward untrusted relay nodes, where the relay nodes only have the channel-amplitude information. To prevent the untrusted relays from intercepting the source message and to achieve positive secrecy rate, the destination-based cooperative jamming technique is used. By maintaining a minimum required secrecy rate, three optimal joint RS and power minimisation schemes are studied. The first objective is minimising the total transmit power consumption, and therefore obtaining the corresponding EE-RS and PA schemes. Second, they focus on relay power minimisation, and third sum power minimisation of the relay and one mobile node by considering a weighted factor are investigated. Closed-form solutions are presented for three practical optimised networks. Finally, some numerical results are provided to show the merits of the proposed scheme. They also give some insights to system design.

Power Allocation and Relay Selection for Multisource Multirelay Cooperative Vehicular Networks

In wireless distributed networks, multisource multirelay cooperative techniques can be used to exploit the spatial and temporal diversity gains to increase the performance or reduce the transmission energy consumption, which is very useful for intelligent transport system (ITS) networks. In this paper, we propose a power allocation method to optimize the hybrid decode–amplify–forward cooperative transmission for multisource multirelay ITS networks as a means to reduce the total power consumption while minimizing outage probability. Specifically, we derive closed-form outage probability expressions and present an energy-efficient relay selection method to form an optimal relay set. It is proven that the proposed methods can solve the joint power allocation and relay selection problem under outage probability constraint. Our performance analysis is supplemented by numerical simulation results to illustrate the significant energy savings of the proposed optimal power allocation and the relay selection methods.

Energy Efficient and Secure Multipoint Relay Selection in Mobile Ad hoc Networks

Nodes in MANETs are battery powered which makes energy an invaluable resource. In OLSR, MPRs are special nodes that are selected by other nodes to relay their data/control traffic which may lead to high energy consumption of MPR nodes. Therefore, employing energy efficient MPR selection mechanism is imperative to ensure prolonged network lifetime. However, misbehaving MPR nodes tend to preserve their energy by dropping packets of other nodes instead of forwarding them. This leads to huge energy loss and performance degradation of existing energy efficient MPR selection schemes. This paper proposes an energy efficient secure MPR selection (ES-MPR) technique that takes into account both energy and security metrics for MPR selection. It introduces the concept of ‘Composite Eligibility Index’ (CEI) to examine the eligibility of a node for being selected as an MPR. CEI is used in conjunction with willingness to provide distinct selection parameters for Flooding and Routing MPRs. Simulation studies reveal the efficiency of ES-MPR in selection of energy efficient secure and stable MPRs, in turn, prolonging the network operational lifetime.

Trust Based Energy Efficient Relay Selection in Multihop Wireless Network

Trust Based Energy Efficient Relay Selection in Multihop Wireless Network

MAC protocol with energy efficient relay selection algorithm for mobile wireless sensor networks

In this paper, we have designed MAC protocol with energy efficient relay selection algorithm. This relay node selection should minimise the energy consumption and MAC overhead, thereby increasing the lifetime of the networks. In this MAC protocol, relay nodes RN are selected based on the MAC overhead and relative energy usage REU parameters. The MAC overhead is incurred by handshake signalling, frame transmission time FTT and frame retransmissions due to transmission failures. The REU is the ratio of cost of generated and forwarded packets to the cost of generated packets. Thus the relay node selection algorithm is proposed based on the above parameters and the node with least MAC overhead and REU is selected as relay node.

MAC protocol with energy efficient relay selection algorithm for mobile wireless sensor networks

MAC protocol with energy efficient relay selection algorithm for mobile wireless sensor networks

Energy-Efficient Relay Selection of Cooperative HARQ based on the Number of Transmissions over Rayleigh-Fading Channels

Cooperative hybrid automatic retransmission request (C-HARQ) is a simple and effective method for wireless communication. Since its performance largely depends on the selection of a relevant relay, the design of an appropriate relay selection scheme is very important. Although various works have been performed on this topic, most of them did not take into account both the “ not memoryless ” and multiple retransmission characteristics of C-HARQ, resulting in the loss of achievable performance. In this paper, we propose a novel cooperative relay selection scheme in a distributed manner called transmission number relaying (TNR) to simultaneously reduce the outage probability and increase the energy efficiency by utilizing the features of C-HARQ. The TNR scheme determines a single relay based on the estimated number of transmissions, which is calculated from the channel condition. Using these numbers instead of just the channel condition improves the outage probability and reduces the total consumed energy. The exact probability of the number of transmissions at each relay and the outage probability are analyzed, and the numerical results show that the proposed scheme significantly improves the outage probability and reduces the total consumed energy. In addition, when the number of available relays is small, the proposed scheme achieves high energy efficiency.

An energy-efficient relay node selection scheme for underwater acoustic sensor networks

Underwater acoustic sensor networks (UWSNs) have many important applications, such as natural resource development, geological oceanography and environmental monitoring. Information collected by sensor nodes must be transmitted to sink node(s) directly or through intermediate nodes. Energy efficiency is a challenging issue for UWSNs because their batteries cannot be removed and are difficult to recharge. Thus, selecting energy-efficient paths from source nodes to sink node(s) is crucial in routing for UWSNs. In this paper, we propose a scheme of relay node selection in UWSNs with a square grid topology for long-term marine monitoring applications. First, we formulate the relay node selection problem as a linear programming problem, where the objective is to maximise the network lifetime. Then, we propose a routing metric that reflects both the transmitting power level and the residual energy of the two-end nodes of each acoustic link. Finally, we evaluate the performance of the proposed relay node selection scheme for different network sizes and different initial battery energy assignments. The simulation results show that the proposed relay node selection scheme can prolong the network lifetime of different network sizes. Compared to a routing algorithm solely based on minimum hop, the performance of the proposed scheme is closer to the optimal value obtained by solving the linear programming problem. Moreover, the network lifetime is further increased if we allow nodes to have different initial energy values based on their work loads.

Energy-Efficient Joint Power Allocation and Relay Selection in Bit Error Rate Constrained Two-Way Relay Network

In this paper, the authors have proposed energy efficient power allocation and relay selection scheme in a two-way amplify-and-forward (AF) relay under bit error rate (BER) constrained network. They have derived an expression for the overall BER for Rayleigh fading channel. Based on minimum power consumption in the network, the authors have addressed the problem of power allocation by converting geometric programming to a convex optimization problem. A closed form solution of power allocation is found, which aims at minimizing total transmit power for the overall BER constrained network. The authors have evaluated minimum total transmit power for two-way AF relay network. Based on minimum total transmit power, a novel relay selection scheme has been proposed. Simulation results demonstrate that the proposed two-way power allocation and relay selection scheme can significantly minimize power consumption under BER constrained network as compared to the existing relay transmission. The proposed power allocation scheme gives 3 dBW gain than one-way relay transmission. The proposed relay selection method also outperforms the random relay selection by 24 dBW. The simulation results are corroborated with the analytical result

Energy efficient relay selection and power allocation for cooperative cognitive radio networks

Owing to environmental, financial and quality of service (QoS) considerations, energy efficient wireless communications have been paid increasing attention under the background of limited energy resource. This study considers a spectrum sharing cognitive radio network, where the primary system leases its radio spectrum to the secondary system for a fraction of time in exchange for secondary users served as relays to assist the transmission of the primary traffic. Based on the cooperative spectrum leasing protocol, the authors formulate a joint optimisation of relay selection and power allocation under QoS requirements to improve energy efficiency (EE). By employing a greedy spectrum sharing (GSS) algorithm, the optimal relay selection, power and sharing time allocation are readily obtained. Monte–Carlo simulations are performed to demonstrate that significant EE improvement is achieved by the proposed GSS algorithm, and that the network performance is enhanced.