Power Control for Battery-Limited Energy Harvesting Communications

A joint power and rate control using game theory algorithm is proposed in heterogeneous networks environment with interference among different systems. It designs a novel revenue function based on the fairness of users' power control and the rate allocation, accompanying with the interference of the primary users caused by different users. The existence and uniqueness of the Nash equilibrium of game theory are derived by rigorous mathematical. Furthermore, simulation results show that the proposed algorithm can improve users' power control and rate allocation significantly.

Power control is important in interference-limited cellular, ad-hoc, and cognitive wireless networks, when the objective is to ensure a certain quality of service to each connection. Power control has been extensively studied in this context, including distributed algorithms that are particularly appealing in ad-hoc and cognitive settings. A long-standing issue is that the power control problem may be infeasible, thus requiring appropriate admission control. The power and admission control parts of the problem are tightly coupled, but the joint problem is NP-hard. In recent work, we developed a convex relaxation-based deflation approach to the joint problem, which was shown to outperform the prior art, and yield close to optimal solutions at moderate computational cost. In this paper, we derive a distributed version of our joint power and admission control algorithm. The algorithm alternates between distributed approximation and distributed deflation - reaching consensus on a user to drop, when needed. Both phases require only local communication and computation, yielding a relatively lightweight distributed algorithm which also attains close to optimal performance.

In cognitive radio networks, power control is necessary to not only decrease the interference among the secondary users (SUs), but also avoid negative impact to the primary users (PUs). Prevalent research works on power control are mainly focus on maximizing SINR as the QoS requirement of SUs under the interference power constraint for PUs. We note that besides achieving a high SINR to guarantee reliable data transmissions, SUs also require to support heterogenous services with different transmission rates. In order to provide flexible transmission rates to each SU, efficient use of networks radio resource requires transmission rate control in addition to transmit power control. In this paper, we consider the problem of joint power and rate control for SUs in cognitive radio network by using non-cooperative game theory. We study how to jointly allocate optimal transmit power and transmission rate given certain QoS requirement of SUs. We analysis of existence, uniqueness and Pareto efficiency of Nash equilibrium for our game. The performance of our proposed joint power and rate control algorithm is investigated by numeral results.

This paper investigates device-to-device (D2D) communication nested in a cellular network, where a pair of D2D users directly exchanges their information using the uplink frequency band of the cellular network. When the D2D user treats the interference from the cellular user as noise, power control at the cellular user is optimal for maximizing the rate of the cellular user while controlling the interference to the D2D user. However, if the D2D user can perform successive interference cancelation (SIC), the cellular user needs to adjust both transmit power and rate to maximize its rate, because the decodability of the interfering signals at the D2D user depends not only on the signal power but also on the rate of the cellular user. To control the interference from the cellular user, we propose a joint transmit power and rate control scheme at the cellular user. Forcing the cellular user to transmit with a reduced data rate compared with the maximum possible rate, given its transmit power, the proposed joint power and rate control scheme efficiently enables SIC at the D2D user. To reduce the computational complexity, we also propose a near-optimal scheme that employs either power control or rate control depending on the channel conditions.

Due to the ever growing need for spectrum, the cognitive radio (CR) has been proposed to improve the radio spectrum utilization. In this scenario, the secondary users (SU) are permitted to share spectrum with the licensed primary users (SU) with a strict condition that they do not cause harmful interference to the cognitive network. In this work, we have proposed an interference model for cognitive radio network that utilizes power or contention control interference management schemes. We derived the probability density function (PDF) with the power control scheme, where the power of transmission of the CR transmitter is guided by the power control law and also with contention control scheme that has a fixed transmission power for all CR transmitter controlled by a contention control protocol. This protocol makes a decision on which CR transmitter can transmit at any point in time. In this work, we have shown that power and contention control schemes are good candidates for interference modeling in cognitive radio system. The impact of the unknown location of the primary receiver on the resulting interference generated by the CR transmitters was investigated and the results shows that the challenges of the hidden primary receivers lead to higher CR-primary interference in respect to higher mean and variance. Finally, the presented results show power control and the contention control scheme are good candidates in reducing the interference generated by the cognitive radio network.

The WCDMA system is intended as a first step towards the third generation digital cellular systems. It is developed to meet the demands of wireless mobile communication in a true multimedia environment, where high packet data transfer and the Internet bearer service play major roles. One of the critical radio resources of WCDMA is power (control). The quality of the transmission can be improved by power control. Number of bits is real constraint in power control. The contribution of this paper is to use gain scheduling for mobile communication. The idea is that the parameters of the power control algorithm are changed according to the quality measurements of the system level. Power control coded on 1 bit and 2 bits is used for multi-base station multi-user simulations. Power control coded on 2/3/4 bits is used for one base station multi-user simulations. Both uplink and downlink transmission are considered.

As the most basic and lowest data node of ubiquitous power Internet of things, power system protection and control equipment plays a vital role in the stable operation of ubiquitous power Internet of things. The current status and problems of power system protection and control equipment manufacturing are discussed. Aiming at the National Equipment Manufacturing Industry Standardization and Quality Improvement Plan, the production intelligent manufacturing standards and related test verification standards of power system protection and control equipment are put forward. Four key points of intelligent manufacturing of power system protection and control equipment are studied. Technical features: intelligent design verification, intelligent production scheduling verification, intelligent production, power control and protection equipment life cycle data management. Through the gradual implementation of these technologies, the level of intelligent manufacturing of protection and control equipment for ubiquitous power network interconnection has been improved, hoping to promote the implementation and application of national equipment manufacturing standards in the power industry.

Introduction One of the important issues in infrastructure-based multi-cell wireless networks is properly associating mobile user equipments (UEs) to the serving BSs. In the literature, this is usually referred to as user association, cell association, cell selection, or BS assignment. We will use the term “cell association” in this chapter. Obviously, in a wireless network with dense deployment of the BSs, the number of potential BSs with which a UE can be associated is increased. The network densification necessitates the need for designing optimal and/or distributed cell association (BSs assignment to UEs) schemes. This is because, if the UEs are not properly associated with BSs, it may result in reduced throughput, increased interference, inefficient energy consumption, and load imbalance, in uplink and/or downlink. In Chapters 6 and 7, it was assumed that cell association is already performed (i.e., fixed BS assignment). In fact, in those chapters a fixed cell association is assumed, under which the power control and joint power and admission control problems were defined and addressed. In this chapter, we assume the BS assigned to each UE is not fixed and can be dynamically determined. Cell association can be performed separately or jointly with other resource allocation schemes. For instance, cell association can be performed based on some metric such as the received (pilot) signal strength, or it can be performed jointly with power control or channel allocation. In this chapter, we first briefly present the system model introduced in Chapter 5 and make a little change in notations to make it suitable for studying the problem of dynamic cell association. Then the joint cell association and power control (CAPC) schemes are studied, followed by a review of the existing approaches for distributed cell association schemes (where cell association is performed separately and independently from the power control). Finally, open challenges and problems are discussed. System Model and Notations We consider the same system model presented in Chapter 5, which is briefly introduced again in this chapter.

This is the second issue of Wireless Communications and Mobile Computing (WCMC) published by John Wiley & Sons, Ltd. The first issue was published ahead of time and presented some excellent review papers from experts in the field. We received great feedback from a number of colleagues about its content and we promise to continue producing excellent issues in the future. If you did not receive your sample copy of the inaugural issue, please let me or any of the regional editors know to arrange to send you a copy. We have selected seven papers to appear in this second issue. These papers span a good range of topics in the area. The first is a review paper by Ralph and Aghvami. They discuss the Wireless Application Protocol (WAP) architecture and characteristics. Then, they investigate the devices that are supported by WAP as well as the drivers and services. These services include quality of service, security, billing, interoperability, and performance engineering. The variety of media types combined with the diversity of Internet connection characteristics raises momentous challenges to the achievement of ubiquitous access to Internet multimedia content. The second paper, by Margaritidis and Polyzos, addresses issues related to this topic. They identify the importance of adaptation to this category. Then, they examine several important factors that influence the design and optimization of the adaptation architecture. In conclusion, they describe current commercial solutions and future trends in application adaptation in conjunction with recent developments towards wireless access to the Internet. The third paper, by Havinga and Smit, discusses also wireless multimedia networking, but focuses more on energy efficiency. The authors identify three key problems and provide possible solutions to overcome them. The efficient management of power-controlled cellular wireless systems is necessary for their deployment success. Power control can be used as a platform for radio resource management and is important for channel fading as well as providing QoS to individual users. Xiao, Shroff and Chong review the developments of distributed power control and related resource management problems in cellular wireless systems. The discussion is concentrated on achieving high efficiency for a power-controlled system while preventing the system from failure. They then review power and rate control schemes proposed for wireless data, and present a framework for utility-based power control as a possible candidate for distributed power control of multimedia wireless systems. In the fifth paper, Arslan and Bottomley review commonly used approaches to channel estimation. This is necessary in adaptive receiver designs used in narrowband and wireless digital communication systems. They consider both time-invariant and time-varying channels in their discussion. They also provide a number of applications that will make use of this standard. On the other hand, Tepedelenliolu, Abdi, Giannakis and Kaveh talk about estimation of Doppler spread and signal strength in wireless systems. They concentrate on estimating the received signal strength, mobile velocity, and other related statistical channel parameters that apply to handoff and adaptive transmission. They provide comparison of the presented schemes based on their modeling and simulation results. Finally, Annamalai and Tellambura present a research paper discussing three new exponential-type bounds derived using the Cauchy–Schwarz bounding technique. They show that these new bounds are found to be tight and useful for a number of applications. They compare these bounds to other well-known exponential type bounds and prove that these perform at least comparable or tighter. We hope that you will enjoy reading this issue and welcome any comments to any of the four editors listed below. Again, we welcome all of you to contribute and encourage your colleagues and libraries to subscribe to this fine publication.

In Long Term Evolution Advanced (LTE-A) heterogeneous networks (HetNets) the choice of power control mechanisms is decisive for ensuring the required user throughput and for controlling the inter-cell interference (ICI) to be under a predefined limit. In HetNets different mobile stations (macro, pico, femto) have different transmission powers resulting in complicated interference scenarios raising the need for application of more efficient power and interference control. In this paper we propose an uplink power and interference control mechanism for HetNets based on a generalized risk management procedure. Based on this we propose a proactive algorithm for uplink power and interference control and illustrate it with a simulation in a simplified HetNet macro — pico cell scenario. Results from simulation experiments show that such an approach could be a solution for dynamic uplink power control in HetNets ensuring reduction of the ICI and increasing the average cell throughput.

Today's data centers face two critical challenges. First, various customers need to be assured by meeting their required service-level agreements such as response time and throughput. Second, server power consumption must be controlled in order to avoid failures caused by power capacity overload or system overheating due to increasing high server density. However, existing work controls power and application-level performance separately, and thus, cannot simultaneously provide explicit guarantees on both. In addition, as power and performance control strategies may come from different hardware/software vendors and coexist at different layers, it is more feasible to coordinate various strategies to achieve the desired control objectives than relying on a single centralized control strategy. This paper proposes Co-Con, a novel cluster-level control architecture that coordinates individual power and performance control loops for virtualized server clusters. To emulate the current practice in data centers, the power control loop changes hardware power states with no regard to the application-level performance. The performance control loop is then designed for each virtual machine to achieve the desired performance even when the system model varies significantly due to the impact of power control. Co-Con configures the two control loops rigorously, based on feedback control theory, for theoretically guaranteed control accuracy and system stability. Empirical results on a physical testbed demonstrate that Co-Con can simultaneously provide effective control on both application-level performance and underlying power consumption.

Power control is important in interference-limited cellular, ad-hoc, and cognitive underlay networks, when the objective is to ensure a certain quality of service to each connection. Power control has been extensively studied in this context, including distributed algorithms that are particularly appealing in ad-hoc and cognitive settings. A long-standing issue is that the power control problem may be infeasible, thus requiring appropriate admission control. The power and admission control parts of the problem are tightly coupled, but the joint optimization problem is NP-hard. We begin with a convenient reformulation which enables a disciplined convex approximation approach. This leads to a centralized approximate solution that is numerically shown to outperform the prior art, and even yield close to optimal results in certain cases - at affordable complexity. The issue of imperfect channel state information is also considered. A distributed implementation is then developed, which alternates between distributed approximation and distributed deflation - reaching consensus on a user to drop, when needed. Both phases require only local communication and computation, yielding a relatively lightweight distributed algorithm with the same performance as its centralized counterpart.

Mobile agents' mobility and power limitation may result in communication delay. Then the network connectivity may be not maintained only by power control or mobility control in mobile decentralized network, so we provide integrated power and mobility control law design methods for preserved connectivity in this paper. Consider preserved connectivity and communication delay may be time varying, we extend previous works of power control and mobility control for connectivity, and design power control methods, integrated power and mobility control methods for power, position and velocity. We get the results that with time increasing, the communication radius approaches to the preserved value, the relative positions converge to the preserved position, and the velocities converge to a constant.

Design of control strategy for reactor power control system of LBE cooled Actinide Burner Reactor (ABR) using system analysis code NUSOL-LMR

In this paper, we consider the delay-sensitive power and transmission threshold control design in S-ALOHA network with FSMC fading channels. The random access system consists of an access point with K competing users, each has access to the local channel state information (CSI) and queue state information (QSI) as well as the common feedback (ACK/NAK/Collision) from the access point. We seek to derive the delay-optimal control policy (composed of threshold and power control). The optimization problem belongs to the memoryless policy K-agent infinite horizon decentralized Markov decision process (DEC-MDP), and finding the optimal policy is shown to be computationally intractable. To obtain a feasible and low complexity solution, we recast the optimization problem into two subproblems, namely the power control and the threshold control problem. For a given threshold control policy, the power control problem is decomposed into a reduced state MDP for single user so that the overall complexity is O(NJ), where N and J are the buffer size and the cardinality of the CSI states. For the threshold control problem, we exploit some special structure of the collision channel and common feedback information to derive a low complexity solution. The delay performance of the proposed design is shown to have substantial gain relative to conventional throughput optimal approaches for S-ALOHA.