低功耗通信系统中的传输能效优化研究

文章主要深入研究低功耗通信系统中传输能效的优化问题。探讨系统级建模、硬件电路设计、软件算法改进以及网络协议优化等方面内容,提出一种基于自适应编码调制、传输功率控制和网络协议优化的综合优化方案。实验结果表明,所提出的方案能够有效提升低功耗通信系统的传输能效和稳定性,为低功耗物联网、可穿戴设备等应用场景提供一种优化的通信解决方案。

双受能端无线传能系统传输能效优化方法研究

针对无线电能传输(WPT)设备在实际中对“一对多”形式日益增长的需求,此处通过构建磁耦合WPT系统等效电路模型,结合LCC拓扑恒流传输特点及双受能端异轴同侧的位置布局,在供能线圈铜耗量固定的前提下,通过设计系统的电气参数来构建供能线圈结构参数以优化传输能效,从而设计了一种两端半圆、中间矩形的跑道形结构的供能线圈,在此基础上搭建起一套采用跑道型供能线圈结构的双受能端磁耦合WPT系统。在直流输入36 V、两个20Ω负载条件下,系统输出总功率可以达到162 W,效率达到87.72%,通过实验验证了理论分析的正确性和系统设计的可行性。

一种多小区多用户能效波束赋形分层优化算法

研究在用户服务质量需求和功率约束等条件下最大化系统能效的多小区多用户系统中的波束赋形技术。首先引入辅助变量将分式形式的非凸优化目标函数转化为凹凸分数形式的优化目标函数,并利用分式规划和低复杂度凸逼近法进行功率分配优化;然后将波束优化问题转化成满足一定约束条件的最小化发射功率优化问题,并利用二阶锥规划求解相应的波束赋形优化问题。仿真结果表明:所提的能效分层优化算法可以经过有限迭代次数逐渐收敛到稳定值;在低发射功率区域,所提算法能够同时获得最大频谱效率和能源效率;而在高发射功率区域,本文算法所获得的能效性能明显优于传统的频谱效率最大化算法。

A New Cochlear Prosthetic System with an Implanted DSP

This paper proposes a cochlear prosthetic system with an implanted digital signal processor （DSP）. This system transmits voice-band signals with a low data rate through the wireless link, free of the data-rate limitation and suitable for future development. By optimizing the speech processing algorithm and the DSP hardware design, the implanted DSP manages to execute the continuous interleaved sampling （CIS） algorithm at a clock frequency of 3MHz and a power consumption of only 1.91mW. With an analytic power-transmission efficiency of the wireless inductive link （40%）, the power overhead caused by the implanted DSP is derived as 2.87roW,which is trivial when compared with the power consumption of existing cochlear prosthetic systems （tens of milliwatts）. With the DSP implanted,this new system can.be easily developed into a fully implanted cochlear prosthesis.

Research on the influence of ocean temperature on XCTD profiler single-mode fiber transmission channel

XCTD, as one of the most important instruments for the deep sea exploration, is an important device for deep-sea hydrological data acquisition. But some difficult technical problems of traditional metal enameled wire channel have become the major bottleneck for XCTD development. Aiming at this problem, this paper puts forward with using single-mode fiber as the transmission channel of XCTD. Firstly, this paper makes a brief analysis on the problems of using enameled wire as transmission channel faces. Secondly, it analyzes the advantages of the single mode fiber technology. Finally, it makes theoretical research and experimental verification of the influence of seawater temperature change on the optical fiber transmission channel. The experimentat results show that the error rate at the transmission rate of 10 MB/S is 0, and the loss can be negligible when the single-mode fiber channel is used in the sea water and the seawater temperature changes from 0 to 20℃. This method will greatly increase the rate of signal transmission and the transmission stability. And this paper shows that using the single-mode fiber as the transmission channel of XCTD has certain feasibility.

Energy-efficient data transmission with non-ideal circuit power for downlink cellular networks

The downlink energy-efficient transmission schedule with non-ideal circuit power over Wreless networks involving a single transmitter and multiple receivers was investigated. According to the special structure of the problem, a novel algorithm called OOSCPMR （the optimal offine scheduling with non-ideal circuit power for multi-receivers） is proposed, and the optimal offine solutions to optimize the energy- efficient transmission policy are found. The packets to be transmitted can be divided into two types where one type of packet is determined to be transmitted using the enrgy- efficient tansmission time, and the other type of packet is determined by the ID moveright algorithm. Finally, an energy-efficient online schedule is developed based on te proposed OOSCPMR algoriAm. Simulation results show that the optima offline transmission schedule provides te lower bound performance for the online tansmission schedule. The proposed optimal offline and online policy is more energy efficient than the existing schemes tat assume ideal circuit power.

Energy efficiency enhancement of two-way amplifier forward relaying with channel estimation error

In order to save energy consumption of two-way amplifier forward(AF) relaying with channel estimation error, an energy efficiency enhancement scheme is proposed in this work. Firstly, through the analysis of two-way AF relaying mode with channel estimation error, the resultant instantaneous SNRs at end nodes is obtained. Then, by using a high SNR approximation, outage possibility is acquired and its simple closed-form expression is represented. Specially, for using the energy resource more efficiently, a low-complexity power allocation and transmission mode selection policy is proposed to enhance the energy efficiency of two-way AF relay system. Finally, relay priority region is identified in which cooperative diversity energy gain can be achieved. The computer simulations are presented to verify our analytical results, indicating that the proposed policy outperforms direct transmission by an energy gain of 3 dB at the relative channel estimation error less than 0.001. The results also show that the two-way AF relaying transmission loses the two-way AF relaying transmission loses its superiority to direct transmission in terms of energy efficiency when channel estimation error reaches 0.03.

HetNet中基于上行CoMP的动态多小区接入算法

提出了HetNet中基于上行CoMP的动态多小区接入算法(UCDS),动态选择协作基站,利用CoMP机制,改善小区边缘用户的上行传输性能。进一步地,提出了基于二次判决的协作小区选择算法(DJCS),以减少参与协作的基站数,降低协作复杂度并节省基站端资源。仿真结果表明,UCDS算法能显著提高边缘用户的平均吞吐率和传输能效,而DJCS算法在保证用户性能的情况下,降低了基站端的能耗。

Steering Vibrational Population Transfer via Double-∑-Type Laser Scheme

The vibrational state-selected population transfer from a highly vibrationally excited level to the ground level is of great importance in the preparation of ultra-cold molecules. By using the time-dependent quantum-wave-packet method, the population transfer dynamics is investigated theoretically for the HF molecule. A double-E-type laser scheme is proposed to transfer the population from the ｜v=16〉 level to the ground vibrational level ｜v=0〉 on the ground electronic state. The scheme consists of two steps： The first step is to transfer the population from ｜v=16〉 to ｜v=7〉 via an intermediate level ｜v=11〉, and the second one is to transfer the population from ｜v=7〉 to ｜v=0〉 via ｜v=3〉. In each step, three vibrational levels form a E-type population transfer path under the action of two temporally overlapped laser pulses. The maximal population-transfer efficiency is obtained by optimizing the laser inten- sities, frequencies, and relative delays. Cases for the pulses in intuitive and counterintuitive sequences are both calculated and compared. It is found that for both cases the population can be efficiently （over 90%） transferred from the ｜v=-16〉 level to the ｜v=0〉 level.

Energy Efficiency Based on Joint Data Packet Fragmentation and Cooperative Transmission

Energy efficiency(EE) is a key requirement for the design of short-range communication network.In order to alleviate energy consumption(EC) constraint,a novel layered heterogeneous mobile cloud architecture is proposed in this paper.Based on the proposed layered heterogeneous mobile cloud architecture,we establish an appropriate energy consumption model,and design an energy efficiency scheme based on joint data packet fragmentation and cooperative transmission and analyze the energy efficiency corresponding to different packet sizes and the cloud size.Simulation results show that,when all nodes of the cloud are accessing the same size of data packet fragmentation,the proposed layered heterogeneous mobile cloud architecture can provide significant energy savings.The results provide useful insights into the possible operation of the strategies and show that significant energy consumption reductions are possible.

Capacity-Power Consumption and Energy-Efficiency Evaluation of Green Wireless Networks

In this paper,we discuss in detail the basic issue of green design and consider an energy efficiency function as the metric to evaluate green cellular networks.Specifically,we investigate the transmit power required for an expected transmission capacity and propose a capacity-power formula based on the energy conservation and the Shannon capacity theorem.Two novel definitions of cell interference depth and handoff dynamic model are introduced and the corresponding expression of energy efficiency function is derived.Numerical results show that the energy efficiency function is closely correlated with the transmitted/received power required and the cell radius.Our work provides a useful basis for research and evaluation on green design and technology of cellular networks.

A cooperative user selection scheme based on energy efficiency and interference factor in cooperative communication systems

With the rapid development of green communications,energy consumption issue plays more and more important role in cooperative communication strategies and communication systems.Based on cooperative transmission model,a cooperative user selection scheme is proposed in consideration of both energy efficiency and interference factor.With the proposed scheme,the selected cooperative user consumes less energy and receives less interference.Furthermore,the main factor is analyzed to affect system performance,including signal-to-noise ratio(SNR)of source user and cooperative user,distance between source user and cooperative user or base station(BS),and fading factor in the transmission model.Through the proposed scheme,energy consumption and influence of interference are jointly taken into account during the cooperative user selection process.Besides,bit error rate(BER)in proposed scheme is also superior to existing schemes.Simulation results are presented to show the performance improvement of the proposed scheme.

Quantum Model of Energy Transport in Collagen Molecules

A semi-quantum model for energy transport in collagen molecules is presented. Soliton-like dynamics of this model is investigated numerically without and with the temperature effect taking into account. It is found that in both the cases energy can transport for a long distance along the collagen chain. This indicates that collagen molecules can be taken as a candidate for the acupuncture channel.

Energy Efficient Power Allocation Scheme for Distributed Antenna Systems with Target BER Constraint

The energy efficiency(EE) of distributed antenna system with quality of service(Qo S) requirement is investigated over composite Rayleigh fading channel,where the shadow fading,path loss and Rayleigh fading are all considered. Our aim is to maximize the EE which is defined as the ratio of the transmission rate to the total consumed power subject to the maximum transmit power of each remote antenna constraint and Qo S(target BER) requirement. According to the definition of EE and using the upper bound of average EE,the optimized objective function is provided. Based on this,utilizing Karush-KuhnTucker conditions and numerical calculation,a suboptimal energy efficient power allocation(PA) scheme is developed,and the closedform expression of PA coefficients is derived. The scheme may obtain the EE performance close to the existing optimal scheme. Moreover,it has relatively lower complexity than the existing scheme because only the statistic channel information and less iteration are required. Simulation results show the presented scheme is valid and can meet the target BER requirement,and the EE can be increased as target BER requirement decreases.

Demonstration of topological wireless power transfer

Recent advances in non-radiative wireless power transfer(WPT)technique essentially relying on magnetic resonance and near-field coupling have successfully enabled a wide range of applications.However,WPT systems based on double resonators are severely limited to short-or mid-range distance,due to the deteriorating efficiency and power with long transfer distance.WPT systems based on multi-relay resonators can overcome this problem,which,however,suffer from sensitivity to perturbations and fabrication imperfections.Here,we experimentally demonstrate a concept of topological wireless power transfer(TWPT),where energy is transferred efficiently via the near-field coupling between two topological edge states localized at the ends of a one-dimensional radiowave topological insulator.Such a TWPT system can be modelled as a parity-time-symmetric Su-Schrieffer-Heeger(SSH)chain with complex boundary potentials.Besides,the coil configurations are judiciously designed,which significantly suppress the unwanted cross-couplings between nonadjacent coils that could break the chiral symmetry of the SSH chain.By tuning the inter-and intra-cell coupling strengths,we theoretically and experimentally demonstrate high energy transfer efficiency near the exceptional point of the topological edge states,even in the presence of disorder.The combination of topological metamaterials,non-Hermitian physics,and WPT techniques could promise a variety of robust,efficient WPT applications over long distances in electronics,transportation,and industry.

Hole mobility enhancement in uniaxial stressed Ge dependence on stress and transport direction

Utilizing a six-band k.p valence band calculations that considered a strained perturbation Hamiltonian, uniaxial stress-induced valence band structure parameters for Ge such as band edge energy shift, split, and effective mass were quantitatively evaluated. Based on these valence band parameters, the dependence of hole mobility on uniaxial stress(direction, type, and magnitude) and hole transport direction was theoretical studied. The results show that the hole mobility had a strong dependence on the transport direction and uniaxial stress. The hole mobility enhancement can be found for all transport directions and uniaxial stess configurations, and the hole transport along the [110] direction under the uniaxial [110] compressive stress had the highest mobility compared to other transport directions and stress configurations.

A novel dopant for spiro-OMeTAD towards efficient and stable perovskite solar cells

2,2’,7,7’-tetrakis-(N,N-di-4-methoxyphenylamino)-9,9’-spirobifluorene(spiro-OMeTAD), as the most commonly used hole transport material(HTM), plays a significant role in the normal structured(n-i-p) high-efficiency perovskite solar cells(PSCs). In general, it is prepared by a halogen solvent(chlorobenzene, CBZ) and needs an ion dopant(lithium bis(trifluoromethanesulfonyl)imide, Li-TFSI) to improve its conductivity and hole mobility. However, such a halogen solvent is not environmentally friendly and the widely used LiTFSI dopant would affect the stability of PSCs. Herein, we develop a non-halogen solvent-tetrahydrofuran(THF)-prepared spiro-OMeTAD solution with a new p-type dopant,potassium bis(fluorosulfonyl)imide(K-FSI), to apply into PSCs. By this strategy, high-hole-mobility spiro-OMeTAD film is achieved. Meanwhile, the potassium ions introduced by diffusion into perovskite surface passivate the interfacial defects. Therefore, a hysteresis-free champion PSC with an efficiency of 21.02% is obtained, along with significantly improved stability against illumination and ambient conditions. This work provides a new strategy for HTMs toward hysteresis-free high-efficiency and stable PSCs by substituting dopants.