基于博弈论功率控制的串行干扰消除算法

无线网络实现串行干扰消除算法可以提高网络吞吐量,在采用串行干扰消除算法的无线网络系统中,如何控制节点间传输功率使系统效用最大化是一个NP-Hard难题。针对此问题提出非合作博弈算法来解决节点间的传输功率控制,提出了串行干扰消除算法功率控制的非合作博弈,证明了纳什均衡,所提算法可以获得较高的无线网络吞吐量,仿真实验证实了分析结果并展示了算法的优越性。     

工业无线传感器网络物理层移动节点的抗干扰Stackelberg博弈模型

针对工业无线传感网络中物理层干扰攻击问题,研究一种移动环境下的博弈功率控制方案。为提高移动sink节点的抗干扰能力,利用Bayesion-Stackelberg博弈模拟移动sink节点和干扰节点的对抗交互行为,通过求出参与博弈的节点最优策略,即sink节点和干扰节点的最佳传输功率,达到合法节点抗干扰的最佳效果,提高通信系统物理层的安全性。Matlab仿真结果表明,相比移动sink节点的其他博弈功率控制算法,本文方案能更有效地提高合法节点抗干扰能力且能耗更低。      

基于多目标的MIMO无线mesh网络信道优化策略

MIMO是一种可有效提高无线网络信道带宽的技术。将MIMO技术应用在无线mesh网络中会遇到信道干扰和无线节点之间无协同策略等问题,导致网络效率降低。基于无线mesh网络中节点的多属性特征,以节点属性和内容分发为约束,提出了基于多目标优化算法与多层分发联合的调度和优化策略。实验结果表明,该算法能有效降低无线mesh网络分发数据过程中的时延,提高网络的吞吐表现和服务质量。     

一种适用于Ad hoc网络的DCF协议自适应功率控制机制

该文对载波检测无线网络中的冲突干扰问题进行了分析,在此基础上提出了一种适用于Ad hoc网络的DCF协议自适应功率控制机制。该机制能根据各个接收节点的通信状况,自适应的调整接收节点的CTS帧发送功率和收方决定的数据帧发送功率。仿真证明,在DCF协议中引入该机制后,不仅能有效节省节点能耗,延长网络的生存时间,还能同时增大网络的频率空间复用度,提高网络的平均吞吐量。     

中继增强的无线蜂窝多小区系统的联合调度与功率控制算法

针对采用全局频率复用的中继增强的无线蜂窝多小区系统,该文考虑多种通信模式并存的混合场景,提出了一种干扰感知的联合资源分配策略。以最大化系统总吞吐量为目标,同时考虑小区间干扰对中继节点与移动站点的影响,以及基站与中继节点各自的发射功率约束。为了降低计算复杂度,针对用户与中继节点配对问题提出了一种基于小区间干扰的调度算法;针对功率控制问题分别提出了一种基于符号规划的最优功率分配算法和一种次优的最小能耗功率分配算法。仿真结果表明,该文所提算法逼近最优资源分配,在系统吞吐量与能量效率等性能方面具有显著优势。     

功率可控的多分组接收优化策略

多分组接收在不改变原有无线网络物理层的基础上,利用解析算法和调度方案,提高无线网络的网络吞吐量。本文通过SIC算法获得各个节点能量—信噪比的规律模型。采用功率调节的方式,扩充可发送数据的节点的可行集合。由于节点的能量调节为线性变化,而节点能否发送为离散事件,这就增加了求解最优节点组合的难度和复杂度。本文提出了节点功率能级的概念,通过对功率进行分级来简化问题。仿真显示,采用功率可控的多分组传输协议后,网络传输速率有了很大提高。     

降低室内无线网络电磁辐射的能量优化算法

无论信道状态如何传统的室内无线网络节点,总是采用增加发射功率的方式以获得较好的通信效果,在一定程度上增大了室内无线网络的电磁辐射强度和网节点能耗.为此研究了室内无线网络节点的电磁辐射和能耗问题.首先给出了在确保通信效果的基础上尽可能降低网络节点发射功率的功率控制模式;然后提出了一种降低无线网络节点发射功率的能量优化算法;采用无线传感器网络的分簇技术和COST-231模型,构建了室内无线网络的路径损耗模型和最小发射功率模型,并实现了网络节点的能量优化.理论分析和仿真结果表明:该算法既保证了原有的通信效果,又降低了网络节点电磁辐射和能耗.     

认知无线网状网中基于差分演化的功率控制与信道分配

信道分配对于提高认知无线网状网性能具有重要作用.考虑到节点功率对网络干扰的影响,定义了网络干扰边及潜在干扰边,通过量化通信功率控制等级,给出了联合功率控制与信道分配的网络模型.提出一种基于差分演化的功率控制与信道分配算法,设计了实数编码规则及相应的约束控制机制以保证个体的有效性,确保算法的快速收敛.一系列仿真实验表明本文算法的有效性.     

基于用户体验质量和系统能耗的异构网络联合接入选择和功率分配策略

为了解决无线网络能耗和用户体验质量的问题,提出了一种应用于异构无线网络环境的基于多目标优化的联合接入选择和功率分配策略。该策略以最小化系统整体能耗和最大化用户平均体验质量为目标,建立了多目标优化联合分配模型,通过差分进化算法得到联合分配模型的最优解集,并结合 TOPSIS 的方法从最优解集中得到折中的联合分配方案。仿真结果表明,本文所提的策略能够有效地降低系统能耗,并提升用户整体的服务体验。     

无线传感器网络基于容量和传输能耗的功率与信道联合博弈算法

针对无线传感器网络(WSNs)日益增大的干扰导致网络容量下降的问题,同时考虑到网络能量有限性,该文综合网络容量和链路传输能耗,构建了高容量低传输能耗的功率控制与信道分配联合博弈模型,并通过理论分析证明该模型存在最优功率和最优信道。继而采用最佳响应策略,在该博弈模型基础上提出了一种功率控制与信道分配联合优化算法(PCOA),理论证明其能收敛到纳什均衡状态,且具有较小的信息复杂度。最后,仿真结果表明,PCOA算法能够达到降低网络干扰和链路能耗,增大网络容量的目的。     

Power control algorithm based on non-cooperative game theory in successive interference cancellation

Wireless Networks - Successive interference cancellation (SIC) is an effective way of multi-packet reception to combat interference in wireless networks. The power control problem among wireless...     

The problem of medium access control in wireless sensor networks

In this article we revisit the problem of scheduled access through a detailed foray into the questions of energy consumption and throughput for MAC protocols in wireless sensor networks. We consider a static network model that rules out simultaneous transmission and reception by any sensor node and consequently requires partitioning of nodes into disjoint sets of transmitters and receivers at any time instant. Under the assumption of circular transmission (reception) ranges with sharp boundaries, a greedy receiver activation heuristic is developed relying on the network connectivity map to determine distinct receiver groups to be activated within disjoint time intervals. To conserve limited energy resources in sensor networks, the time allocation to each receiver group is based on the residual battery energy available at the respective transmitters. Upon activating each receiver group separately, the additional time-division mechanism of group TDMA is imposed to schedule transmissions interfering at the non-intended destinations within separate fractions of time in order to preserve the reliable feedback information. The two-layered time-division structure of receiver activation and group TDMA algorithms offers distributed and polynomial-time solutions (as required by autonomous sensor networks) to the problems of link scheduling as well as energy and throughput-efficient resource allocation in wireless access. The associated synchronization and overhead issues are not considered in this article.     

Energy Management Fuzzy Logic Supervisory for Electric Vehicle Power Supplies System

This paper introduces an energy management strategy based on fuzzy logic supervisory for road electric vehicle, combining a fuel cell power source and two energy storage devices, i.e., batteries and ultracapacitors. The control strategy is designed to achieve the high-efficiency operation region of the individual power source and to regulate current and voltage at peak and average power demand, without compromising the performance and efficiency of the overall system. A multiple-input power electronic converter makes the interface among generator, energy storage devices, and the voltage dc-link bus. Classical regulators implement the control loops of each input of the converter. The supervisory system coordinates the power flows among the power sources and the load. The paper is mainly focused on the fuzzy logic supervisory for energy management of a specific power electronic converter control algorithm. Nevertheless, the proposed system can be easily adapted to other converters arrangements or to distributed generation applications. Simulation and experimental results on a 3-kW prototype prove that the fuzzy logic is a suitable energy management control strategy.     

Joint power control and user scheduling for backbone-assisted industrial wireless networks with successive interference cancellation

In a backbone-assisted industrial wireless network (BAIWN), the technology of successive interference cancellation (SIC) based non-orthogonal multiple access (NOMA) provides potential solutions for improving the delay performance. Previous work emphasizes minimizing the transmission delay by user scheduling without considering power control. However, power control is beneficial for SIC-based NOMA to exploit the power domain and manage co-channel interference to simultaneously serve multiple user nodes with the high spectral and time resource utilization characteristics. In this paper, we consider joint power control and user scheduling to study the scheduling time minimization problem (STMP) with given traffic demands in BAIWNs. Specifically, STMP is formulated as an integer programming problem, which is NP-hard. To tackle the NP-hard problem, we propose a conflict graph-based greedy algorithm, to obtain a sub-optimal solution with low complexity. As a good feature, the decisions of power control and user scheduling can be made by the proposed algorithm only according to the channel state information and traffic demands. The experimental results show that compared with the other methods, the proposed method effectively improves the delay performance regardless of the channel states or the network scales.

     

Parameter identification and vibration control in Modular manipulators

The joint parameters of modular manipulators are prerequisite data for effective dynamic control. A method for identifying these parameters using fuzzy logic was devised to study modular redundant robots. Experimental modal analysis and finite element modeling were exploited to model the dynamics. The joint parameters of a nine degrees-of-freedom (9-DOF) modular robot have been identified. In addition, active vibration control based on a neural network and a genetic algorithm were investigated. Ideal control simulation results for a reduced dynamic model of the 9-DOF modular robot were then derived.     

Adaptive neuro-fuzzy control of a flexible manipulator

This paper describes an adaptive neuro-fuzzy control system for controlling a flexible manipulator with variable payload. The controller proposed in this paper is comprised of a fuzzy logic controller (FLC) in the feedback configuration and two dynamic recurrent neural networks in the forward path. A dynamic recurrent identification network (RIN) is used to identify the output of the manipulator system, and a dynamic recurrent learning network (RLN) is employed to learn the weighting factor of the fuzzy logic. It is envisaged that the integration of fuzzy logic and neural network based-controller will encompass the merits of both technologies, and thus provide a robust controller for the flexible manipulator system. The fuzzy logic controller, based on fuzzy set theory, provides a means for converting a linguistic control strategy into control action and offering a high level of computation. On the other hand, the ability of a dynamic recurrent network structure to model an arbitrary dynamic nonlinear system is incorporated to approximate the unknown nonlinear input–output relationship using a dynamic back propagation learning algorithm. Simulations for determining the number of modes to describe the dynamics of the system and investigating the robustness of the control system are carried out. Results demonstrate the good performance of the proposed control system.     

Full-duplex overlay cognitive wireless powered communication network using RF energy harvesting

In this paper, a novel full-duplex overlay cognitive wireless powered communication network (FD-OCWPCN) is proposed where a full-duplex (FD) hybrid-access point (H-AP) supports the full access of all battery-free secondary users (SUs). The H-AP broadcasts wireless power to empower the nearby SUs in the downlink (DL) phase while decoding the information transmitted uplink (UL) phase by the SUs, simultaneously. To overcome the self-interference (SI) phenomenon in FD-OCWPCN, the problem of maximizing the system sum-throughput with optimal UL-DL transmission/reception time and H-AP’s transmit power allocation is considered. This problem is non-convex under perfect/imperfect SI cancelation (SIC), so we employ the active interference temperature control and the gradient projection techniques to effectively reduce it into a convex problem. Closed-form expressions for the perfect/imperfect SIC cases are also derived. To assess the performance of the FD-OCWPCN, a comparison with a half-duplex OCWPCN (HD-OCWPCN) is provided. The achievable average sum-throughput for different FD/HD-OCWPCN is compared in the context of the average and peak transmit power at the H-AP, the number of SUs, path loss exponent and fairness metric. The simulation results depict the superiority of the FD-OCWPCN over the HD-OCWPCN for the perfect SIC and the effective imperfect SIC.

     

Energy-efficiency of MIMO and cooperative MIMO techniques in sensor networks

We consider radio applications in sensor networks, where the nodes operate on batteries so that energy consumption must be minimized, while satisfying given throughput and delay requirements. In this context, we analyze the best modulation and transmission strategy to minimize the total energy consumption required to send a given number of bits. The total energy consumption includes both the transmission energy and the circuit energy consumption. We first consider multi-input-multi-output (MIMO) systems based on Alamouti diversity schemes, which have good spectral efficiency but also more circuitry that consumes energy. We then extend our energy-efficiency analysis of MIMO systems to individual single-antenna nodes that cooperate to form multiple-antenna transmitters or receivers. By transmitting and/or receiving information jointly, we show that tremendous energy saving is possible for transmission distances larger than a given threshold, even when we take into account the local energy cost necessary for joint information transmission and reception. We also show that over some distance ranges, cooperative MIMO transmission and reception can simultaneously achieve both energy savings and delay reduction.     

Adaptive closed-loop power control algorithms for CDMA cellular communication systems

Power control has been widely studied and shown to be crucial for the capacity and performance of direct-sequence code-division multiple-access (DS-CDMA) systems. Practical implementations typically employ fast closed-loop power control, where transmitters adjust their transmit powers according to commands received in a feedback channel. The loop delay resulting from the measurements, processing, and transmission of the power control commands can result in oscillations of the transmission powers and lead to degradation in the system performance. In this paper we present new adaptive closed-loop power control algorithms that are able to alleviate the effect of the loop delay. The algorithms are based on self-tuning controllers designed for a log-linear model of the power control process. We carried out computational experiments on a DS-CDMA network using the distributed constrained power control (DCPC) as a reference algorithm. Practical versions of the algorithms are also provided and they were compared with the fixed-step power control (FSPC) algorithm employed in the IS-95 and WCDMA systems. The numerical results indicate that our algorithms can significantly improve the radio network capacity without any increase in power control signaling.     

A medium access protocol exploiting multiuser-detection in CDMA ad-hoc networks

A new medium access protocol which exploits the physical layer capability of multiuser detection is proposed to help in improving the throughput/delay performance of ad-hoc networks. When more than one node has packets buffered for a common node in the neighborhood, all such nodes can simultaneously transmit their packets to the common receiver after reserving their surrounding channel. This is achieved in our protocol by extending the (sender-initiated) CSMA/CA collision avoidance framework by the receiver-initiated medium access technique and incorporating the transmission power control. We analyze the improvement in the throughput that can be achieved over the basic sender-initiated collision avoidance protocol in the network. Since the throughput improvement via multi-packet reception is influenced by the network layer activity as well, the performance of our protocol rolls back to that of the basic sender-initiated protocol in case of no coordination from the network layer. For the evaluation of performance of our protocol we simulate ad-hoc networks for different network topologies and traffic configurations. We observe the scheme to be capable in significantly improving the throughput/delay performance of the network.