Effects of Electromagnetic Waves with LTE and 5G Bandwidth on the Skin Pigmentation In Vitro

With the rapid growth of wireless communication devices, the influences of electromagnetic fields (EMF) on human health are gathering increasing attention. Since the skin is the largest organ of the body and is located at the outermost layer, it is considered a major target for the health effects of EMF. Skin pigmentation represents one of the most frequent symptoms caused by various non-ionizing radiations, including ultraviolet radiation, blue light, infrared, and extremely low frequency (ELF). Here, we investigated the effects of EMFs with long-term evolution (LTE, 1.762 GHz) and 5G (28 GHz) bandwidth on skin pigmentation in vitro. Murine and Human melanoma cells (B16F10 and MNT-1) were exposed to either LTE or 5G for 4 h per day, which is considered the upper bound of average smartphone use time. It was shown that neither LTE nor 5G exposure induced significant effects on cell viability or pigmentation. The dendrites of MNT-1 were neither lengthened nor regressed after EMF exposure. Skin pigmentation effects of EMFs were further examined in the human keratinocyte cell line (MNT-1-HaCaT) co-culture system, which confirmed the absence of significant hyper-pigmentation effects of LTE and 5G EMFs. Lastly, MelanoDerm™, a 3D pigmented human epidermis model, was irradiated with LTE (1.762 GHz) or 5G (28 GHz), and image analysis and special staining were performed. No changes in the brightness of MelanoDerm™ tissues were observed in LTE- or 5G-exposed tissues, except for only minimal changes in the size of melanocytes. Collectively, these results imply that exposure to LTE and 5G EMFs may not affect melanin synthesis or skin pigmentation under normal smartphone use condition.     

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).     

LTE技术在铁路通信系统中的应用

文章简要介绍了 LTE 技术,指出了下一代铁路通信系统应该采用 LTE 技术。着重分析了单元重载铁路和高速铁路 LTE 无线通信系统,从其网络架构、关键技术、信道估计技术等几个方面进行阐述。     

Cross-layer optimized authentication and error control for wireless 3D medical video streaming over LTE

3D video for tele-medicine applications is gradually gaining momentum since the 3D technology can provide precise location information. However, the weak link for 3D video streaming is the necessary wireless link of the communication system. Neglecting the wireless impairments can severely degrade the performance of 3D video streaming that communicates complex critical medical data. In this paper, we propose systematic methodology for ensuring high performance of the 3D medical video streaming system. First, we present a recursive end-to-end distortion estimation approach for MVC (multiview video coding)-based 3D video streaming over error-prone networks by considering the 3D inter-view prediction. Then, based on the previous model, we develop a cross-layer optimization scheme that considers the LTE wireless physical layer (PHY). In this optimization, the authentication requirements of 3D medical video are also taken into account. The proposed cross-layer optimization approach jointly controls and manages the authentication, video coding quantization of 3D video, and the modulation and channel coding scheme (MCS) of the LTE wireless PHY to minimize the end-to-end video distortion. Experimental results show that the proposed approach can provide superior 3D medical video streaming performance in terms of peak signal-to-noise ratio (PSNR) when compared to state-of-the-art approaches that include joint source-channel optimized streaming with multi-path hash-chaining based-authentication, and also conventional video streaming with single path hash-chaining-based authentication.     

LTE系统多小区上行联合功控算法

针对传统的小区内开环功率控制算法通常以提升本小区的吞吐量性能为目标，忽略了当前小区用户对邻小区用户同频干扰的问题，为提升边缘用户性能的同时兼顾系统整体性能，提出了一种LTE系统小区间上行联合功率控制（UJPC）算法。该算法采用单基站三扇区为系统模型，以最优化系统吞吐量比例公平函数为目标，首先根据最小信干噪比（SINR）约束值和用户最大发射功率这两个约束条件得到相应的数学优化模型，然后采用连续凸近似的方法求解优化问题得出各个基站所管辖的小区内所有用户的最优发射功率。仿真结果表明，与基准的开环功控方案相比，联合功控方案在保证系统平均频谱利用率的情况下能够较大幅度地提高小区边缘频谱利用率，其最佳性能增益能达到50%。     

长期演进系统基于加权平均时延的下行资源调度

针对长期演进（LTE）移动通信系统下行链路传输中多用户的实时（RT）与非实时（NRT）业务传输性能需求问题，提出一种基于用户加权平均时延的改进型的最大加权延时优先（MLWDF）资源调度算法。该算法在考虑信道感知与用户服务质量（QoS）感知的基础上引入反映用户缓冲区状态的加权平均时延因子，该因子通过用户缓冲区中待传输数据与已发送数据的平均时延均衡得到，使具有较大时延和业务量的实时业务优先调度，提升了用户的性能体验。理论分析与链路仿真表明，提出算法在保证各业务时延及公平性的基础上，提升了实时业务的QoS性能，在用户数量达到50的条件下，对比MLWDF算法实时业务的丢包率降低了53.2%，其用户平均吞吐量提升了44.7%，虽牺牲了非实时业务的吞吐量，但仍优于VT-MLWDF算法。实验结果表明，所提算法在多用户多业务传输条件下提升了实时业务的传输性能，并在QoS性能上明显优于对比算法。     

eHRPD技术研究及测试方法

演进的高速数据分组技术（eHRPD）在CDMAEV-DO网络与LTE网络互操作中扮演着关键角色,它实现了网络互通和无缝切换,并提供业务上的连续,同时由于中国电信及美国Verizon等各大CDMA运营商对于LTE网络的需求,eHRPD技术及其测试变得更为重要。本文将对eHRPD的相关技术及其常用的测试方法,依据的相关技术及测试标准,以及它的未来发展进行介绍。     

LTE核心网安全缺陷的研究

演进分组核心(Evolved Packet Core,EPC)是长期演进(Long Term Evolution,LTE)网络的核心网,它是一个支持全IP的、高速率的、基于分组的和低时延的扁平型网络,给人们带来良好用户体验的同时,也引入了一些安全隐患。主要从LTE核心网架构、接口和协议方面研究了LTE核心网面临的安全缺陷,分析了其可能导致的安全威胁,并提出了一系列安全性增强方案,使LTE系统更加安全。     

基于MR弱覆盖提升TD-LTE终端驻留比的方法

LTE驻留比作为LTE网络优化的重要参数，移动在多网并存的情况下，令更多的用户体验到更快更好的网络是运营商的奋斗目标。本文通过调整弱覆盖参数的方法来提高LTE驻留比及MR覆盖率，从而让更多的用户驻留在4G上，实验证明该方法对LTE驻留比的提升有一定作用。