LTE及其关键技术介绍

LTE计划是3GPP最近两年启动的最大科研项目,目标是在相当程度上推动3G技术的发展,并满足人们未来十年左右对于移动通信的技术要求。对LTE计划进行了简要介绍,并重点对LTE计划中系统框架演进和链路层以及物理层的发展进行了一些讨论。     

Energy transport in boundary driven quantum spin systems: One-way street phenomenon in models with long range interactions

We address the investigation of non trivial properties of the energy current in boundary driven XXZ quantum spin models. In specific, we focus on the occurrence of the one-way street phenomenon in asymmetrical chains, a phenomenon stronger than rectification, which establishes the existence of a unique way for the energy current in the absence of external magnetic field, that is, the magnitude and direction of the energy flow does not change as we invert the baths at the boundaries. For general target polarizations at the boundaries, we show that such a phenomenon holds in the presence of long range interactions, ingredient which increases the flow and the rectification in chains of classical oscillators, and so, of interest in the study of manipulation and control of the energy flow.     

TD-SCDMA的长期演进与HSPA+增强技术

为了提高TD-SCDMA系统的传输速率,向国际电联IMT-Advanced所提技术指标迈进,TD-SCDMA的演进策略提上了研究议程。鉴于TD—SCDMA的短期演进HSPA（包括HSDPA和HSUPA）无法满足IMT-Advanced的要求,提出了HSPA＋和LTE的概念。本文首先介绍了TD-SCDMA未来演进和发展的趋势,包括TD-SCDMA的增强、短期演进、中长期演进以及基于IMT-Advanced的4G等。然后重点分析了HSPA＋的关键技术和协议架构等,最后对LTE的帧结构和多址方式进行了分析,提出了演进时的关键点和对策。     

长程差分吸收光谱技术气体浓度反演误差的定量估计

长程差分吸收光谱法(LP-DOAS)是基于最小二乘原理来反演大气痕量气体浓度的。LP-DOAS能对痕量气体进行高灵敏的测量,但是还没有统计的方法定量确定LP-DOAS反演误差。痕量气体的吸收通常很弱,外来影响因素决定了检测限和测量精度,其被误当做真正的吸收,增加了没有统计特性的噪声到残差中,导致最小二乘拟合误差(err(LSQ))有一个明显的误估计。研究采用蒙特卡罗方法,通过残差的循环移位定量确定差分吸收光谱法反演气体浓度的误差。实验结果表明,蒙特卡罗方法可以定量估计差分吸收光谱法反演误差,误估计因子为1.13,而err(LSQ)为3.12。     

Thermodynamics of Squeezed State for Mesoscopic RLC Circuits

We present a density matrix of a mesoscopic RLC circuits to make it possible to analyze the connection between the initial condition and the certain temperature. Our results show that the quantum state evolution will be closely related to the initial condition; the system evolves to generalized coherent state if it is in ground state initially, and evolves to squeezed state if it is in excited state initially. In addition, we also obtain squeezed minimum uncertainty state with satisfying certain condition in mesoscopic RLC circuit.     

用于长脉冲大功率微波系统的高压调制电源

为ＨＬ－１Ｍ装置上的ＬＨＣＤ和ＥＣＲＨ长脉冲大功率微波系统研制的主调制电源,已达到了－７０ＫＶ、３５Ａ的输出指标。应用该电源首次实现了ＴＭ－７０３Ｆ型大功率调整管在１ｓ长脉冲下的运行和双大功率高压调制器的并联运行,在没有ＣＲＯＷＢＡＳＲ保护系统的情况下采用有效的快速保护措施实现了长期的稳定可靠运行。     

A narrow-frame antenna for WWAN/LTE/WiMAX/WLAN mobile phones

In this paper, we present a novel narrow-frame antenna with a size of 75 × 8 × 5.8 mm³ for 5.7 in. mobile phones. The antenna mainly consists of a monopole with four branches that are coupled to a two-branch grounded strip. Our antenna is able to cover more bands than other narrow-frame antennas by excitation of several resonant modes. The improved range of the antenna covers the following eleven bands: LTE700, GSM850, GSM900, DCS, PCS, UMTS, LTE2300, LTE2500, LTE3400 (3400–3800 MHz)/WiMAX3.5 GHz (3400–3650 MHz), WLAN5.2 GHz (5150–5350 MHz) and WLAN5.8 GHz (5725–5875 MHz). Another advantage of the proposed antenna is that it does not need any lumped element to match the antenna. The working principles of the proposed antenna are thoroughly studied. A prototype of the proposed antenna is fabricated and measured, with the results in good agreement with the simulation results.     

UEs Power Reduction Evolution with Adaptive Mechanism over LTE Wireless Networks

At present, the major drawback for mobile phones is the issue of power consumption. As one of the alternatives to decrease the power consumption of standard, power-hungry location-based services usually require the knowledge of how individual phone features consume power. A typical phone feature is that the applications related to multimedia streaming utilize more power while receiving, processing, and displaying the multimedia contents, thus contributing to the increased power consumption. There is a growing concern that current battery modules have limited capability in fulfilling the long-term energy need for the progress on the mobile phone because of increasing power consumption during multimedia streaming processes. Considering this, in this paper, we provide an offline meaning sleep-mode method to compute the minimum power consumption comparing with the power-on solution to save power by implementing energy rate adaptation (RA) mechanism based on mobile excess energy level purpose to save battery power use. Our simulation results show that our RA method preserves efficient power while achieving better throughput compared with the mechanism without rate adaptation (WRA).     

The effects of resource limitation and consensual incentives on cooperation

Exploring the evolution of cooperation has been one of the most challenging topics and attracted increasing attention in various realms. Hereby, we institute an analytic model where the relationship between the common benefits and contributions is the typical saturation nonlinearity. We investigate the evolutionary dynamics of cooperation with and without consensual incentives respectively. The population always evolves to full defection when the incentives are absent. Cooperation, however, can be promoted by consensual incentives when the degree of cooperators' preferences for incentives is great. There exists an intermediate amount of resources at which the positive effect of consensual incentives on cooperation is minimized. Furthermore, there is a U-shape relationship between the degree of cooperators' preference for an incentive and the evolution of cooperation. A greater basin of full cooperation can be induced when the cooperators' preference for reward is more pronounced than that for punishment.     

Evolution on a Smooth Landscape: The Role of Bias

The role of mutational bias in evolution on a smooth landscape is investigated. We consider both a finite-length genome where the bias increases linearly with the fitness, and an infinite genome with a fixed bias. We present simulations of finite populations in a waiting time model, showing both the nonequilibrium dynamics and the equilibrium fitness distributions that are reached. We compute the equilibrium analytically in several cases, using approximate direct solution of the master equations and truncated hierarchies.