Energy Efficient Relay Research Articles

Energy-Efficient Relay Transmission for WBAN: Energy Consumption Minimizing Design With Hybrid Supervised/Reinforcement Learning

Energy-Efficient Relay Transmission for WBAN: Energy Consumption Minimizing Design With Hybrid Supervised/Reinforcement Learning

Energy-Efficient Relay Node Placement in Wireless Heterogeneous Networks with Capacity Constraints

In wireless heterogeneous networks (HetNets), rational relay node (RN) placement can not only expand network coverage and capacity, but also significantly reduce energy consumption of the network. However, existing RN placement schemes mainly focus on improving network performance, and do not take the network energy consumption and capacity constraints of RNs into consideration, which makes their solutions impractical. Therefore, in this paper, we investigate energy-efficient RN placement (EERPL) problem, and try to reduce energy consumption of a wireless HetNet within the range of RN’s capacity constraints. More specifically, we first present a fine-grained energy consumption model and formulate the EERPL problem, which can be translated to the degree constrained minimum Steiner tree problem. Then, we propose a heuristic RN-placement algorithm HBAPS, which involves two steps, i.e., generating an initial minimum-energy RN placement solution and adjusting the solution to be with in the capacity constraints. Finally, extensive simulations are conducted in both randomly generated scenarios and real trace-based scenarios. Experimental results demonstrate that HBAPS achieves nearly optimal results when the scenario is small, and even in a large scenario, the proposed algorithm still obtains proper solutions within the acceptable time, and outperforms the other two existing heuristic algorithms.

Ultragreen Relay Transmission With Wireless Power Transfer for Advanced IoT: Session-Specific Analysis and Optimization

Reliable and energy-efficient wireless transmission is of critical importance to the success of future advanced Internet of Things (IoT). Due to the sporadic nature of IoT transmissions, the energy consumption of the individual IoT transmission session varies dramatically with the instantaneous operating environment as well as the quality of service (QoS) requirements. In this paper, we analyze and design the energyefficient relay transmission systems from an individual data transmission session perspective. Specifically, we consider a dualhop transmission system with a decode-and-forward relay that is solely powered by wireless power transfer from source node. For both time switching and power splitting modes of simultaneous power and information transmission, we analyze and minimize the total energy consumption of the system when transmitting a fixed amount of data, under a piecewise linear energy harvesting (EH) model. Closed-form expressions for optimal transmission parameters are obtained with and without the consideration of latency constraint. Through selected numerical results, we illustrate various design tradeoffs between energy consumption and latency constraint. We show that with optimal transmission parameters, relay transmission with energy transfer can achieve considerable energy saving compared to direct transmission when the direct link quality is poor and the latency constraint is not stringent. We also show that with optimized parameters, power splitting mode leads to lower energy consumption and smaller transmission duration than time switching mode, at the cost of higher implementation complexity.

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

Energy-Efficient Relay Tracking and Predicting Movement Patterns with Multiple Mobile Camera Sensors

Camera sensor networks (CSN) have been widely used in different applications such as large building monitoring, social security, and target tracking. With advances in visual and actuator sensor technology in the last few years, deploying mobile cameras in CSN has become a possible and efficient solution for many CSN applications. However, mobile camera sensor networks still face several issues, such as limited sensing range, the optimal deployment of camera sensors, and the energy consumption of the camera sensors. Therefore, mobile cameras should cooperate in order to improve the overall performance in terms of enhancing the tracking quality, reducing the moving distance, and reducing the energy consumed. In this paper, we propose a movement prediction algorithm to trace the moving object based on a cooperative relay tracking mechanism. In the proposed approach, the future path of the target is predicted using a pattern recognition algorithm by applying data mining to the past movement records of the target. The efficiency of the proposed algorithms is validated and compared with another related algorithm. Simulation results have shown that the proposed algorithm guarantees the continuous tracking of the object, and its performance outperforms the other algorithms in terms of reducing the total moving distance of cameras and reducing energy consumption levels. For example, in terms of the total moving distance of the cameras, the proposed approach reduces the distance by 4.6% to 15.2% compared with the other protocols that do not use prediction.

Deep learning-based energy-efficient relay precoder design in MIMO-CRNs

This paper investigates the problem of energy efficient relay precoder design in multiple-input multiple-output cognitive relay networks (MIMO-CRNs). This is a non-convex fractional programming problem, which is traditionally solved using computationally expensive optimization methods. In this paper, we propose a deep learning (DL) based approach to compute an approximate solution. Specifically, a deep neural network (DNN) is employed and trained using offline computed optimal solution. The proposed scheme consists of an offline data generation phase, an offline training phase, and an online deployment phase. The numerical results show that the proposed DNN provides comparable performance at significantly lower computational complexity as compared to the conventional optimization-based algorithm that makes the proposed approach suitable for real-time implementation.

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

Residual-Energy Aware Modeling and Analysis of Time-Varying Wireless Sensor Networks

In this letter, the residual-energy aware feature of a sensor node in time-varying wireless sensor networks (WSNs) is analyzed and modeled as a Markov chain, upon which the state-transition probability (STP) about the energy level of any node with undetermined and deterministic residual energy can be evaluated. Based on Markov chain and energy-efficient relay search region models, an energy-efficient routing algorithm is proposed to further analyze the impact of STP with known residual energy on extending network lifetime of time-varying WSNs. Simulation results show that the proposed algorithm can effectively extend network lifetime even more than twice while holding a better energy efficiency as compared with the algorithm without considering node-residual energy changes.

Evaluation of the Mobility Aware Energy Efficient Multipoint Relay Link Optimized Routing Protocol for Vehicular Ad HOC Networks

Evaluation of the Mobility Aware Energy Efficient Multipoint Relay Link Optimized Routing Protocol for Vehicular Ad HOC Networks

Towards energy efficient relay deployment in multi‐user LTE‐A networks

Communication using relay node (RN) cooperation is attractive research interest since it supports wide area coverage and high data rates. RNdeployment problem in multiple users long-term evolution-advanced (LTE-A) network is a challenging issue. In this article, the RN deployment problem for a single carrier-frequency division multiple access uplink system is considered. The total energy efficiency (EE) and average EE for multi-user single-relay in the LTE-A network are considered as the performance measures to select the optimum position of RN. Two types of users are deployed: guaranteed bit rate and non-guaranteed bit rate when performing load balancing that can influence the selection of the optimum position of RN. Simulation results show that the EE is increased by 10% based on load balancing compared to unbalanced loaded network. The optimum position of RN at 75% of a cell radius towards the cell edge can significantly improve the EE.

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.

Energy Efficient V2X-Enabled Communications in Cellular Networks

Vehicle-to-everything (V2X) communications, which provide wireless connectivity among vehicles, roadside drivers, passengers, and pedestrians, are attracting great interest. In this paper, we propose an energy-efficient relay assisted transmission scheme based on V2X communications in the uplink cellular networks for delay insensitive applications. We aim to maximize energy efficiency of the uplink while considering both the circuit power and transmit power consumption, as well as the delay constraint. The optimal resource allocation for direct transmission mode and V2X-enabled transmission mode are derived. For the V2X-enabled transmission mode, we first consider the transmission without the delay constraint and obtain the corresponding optimal power allocation. Based on the obtained result, we further propose the optimal resource allocation policy that satisfies the delay constraint and minimizes the energy consumption. Simulation results show that there exists an energy-delay tradeoff and the proposed V2X-enabled scheme can achieve significant energy saving with an acceptable delay compared with the traditional direct scheme, the decoding-and-forward based transmission scheme, and the opportunistic store-carry and forward based transmission scheme, especially when the cell radius is not small.

Energy-Efficient Relay Assignment and Power Control in Multi-User and Multi-Relay Networks

We consider a multiuser multirelay network where each source communicates with its destination via an assigned relay. To ensure fairness among the users, the minimum of the users’ energy efficiencies (in bit-per-Joule) is jointly maximized with respect to the relay assignment and transmit power of both source and relay nodes. The resulting algorithm is provably convergent, requires limited complexity, and significantly outperforms the baseline scenario in which no joint optimization of transmit powers and relay assignment is performed.

Relay node selection with energy efficient routing using hidden Markov model in wireless sensor networks

Wireless sensor based routing is a challenging issue in the context of convergecast routing. In order to counter these issues the relay nodes share the burden of forwarding in multi-hop routing. In this research to counter the effect energy efficient relay node routing (ERNR) algorithm is proposed. ERNR relay nodes are found among the group of member nodes based on the residual energy of the node using Voronoi cells. The selected relay nodes with two hop neighbours form virtual subsets of cluster. The cluster head is then used to allocate the TDMA time slots to its neighbours based on the Hidden Markov prediction model. The proposed technique is evaluated with existing relay node based routing schemes and the performance of the ERNR algorithm yields significant improvements while considering energy related metrics.

Energy Efficient Bidirectional Massive MIMO Relay Beamforming

In this paper, we investigate the global energy efficiency of a bidirectional amplify-and-forward relay MIMO system. It is assumed that the relay serves two end-users, each requiring a minimum target rate. Two algorithms are proposed, a suboptimal one with lower complexity, and an optimal one with slightly higher complexity. We present numerical results that compare the two algorithms and exhibit several optimality properties concerning the global energy efficiency function.

QoS Improved Energy Efficient Cooperative Relaying in Heterogeneous Networks Using Heterogeneous Relays

Cooperative communication is a crucial technology to sustain QoS of mobile user with increased energy efficiency. To improve QoS of cell edge users, energy efficiency and network utilization, cooperative communication can be used in heterogeneous networks. Source, destination and relays are multiple radio access nodes in heterogeneous networks hence source can communicate to relay and destination using one radio mode and relay can select some other efficient radio mode to retransmit message to destination. In this paper, QoS improved energy efficient radio mode and optimal relay(Q-EERR) selection algorithm with heterogeneous relays is proposed, in which each relay node considers dynamic variation of individual radio networks and efficiently select radio mode using Boltzmann–Gibb’s learning algorithm to retransmit message with required QoS and optimized energy. A novel heterogeneous relays introduced in proposed work act as store carry and forward relay (SCFR) for non real time services and decode and forward relay (DFR) for real time services. The proposed Q-EERR algorithm with heterogeneous relays is verified for real time services (voice and video conferencing), elastic service (FTP) and performances are compared with existing energy efficient relay and radio mode (EERR) selection algorithm with DFR and SCFR. It increases QoS of different services, network performance and reduces average transmit power compared with existing algorithm.

Energy Efficient Relaying For Target Coverage In Dense Wireless Sensor Networks

Energy Efficient Relaying For Target Coverage In Dense Wireless Sensor Networks

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.