Rapid growth of wireless communication services in recent decades has created a huge demand of radio spectrum. Spectrum scarcity and utilization inefficiency limit the development of wireless networks. Cognitive radio is a promising tech- nology that allows secondary users to reuse the underutilized licensed spectrum of primary users. The major challenge for spectrum sharing is to achieve high spectrum efficiency while making non-intrusive access to the licensed bands. This requires in- formation of availability and quality of channel resources at secondary transmitters, however, is difficult to be obtained perfectly in practice.
标签： Opportunistic Spectrum Sharing
上传时间： 2020-05-31
上传用户：shancjb
Mobile operators must continuously pursue cost‐ effective and efficient solutions to meet the high data demand requirements of their subscribers. Limited spectrum allocations and non‐contiguous spectrum blocks continue to pose challenges for mobile operators supporting large data uploads and downloads across their networks. With the increase in video and social media content, the challenges have increased exponentially.
标签： qorvo-carrier-aggregation-fundame ntals
上传时间： 2020-05-31
上传用户：shancjb
This paper presents a Hidden Markov Model (HMM)-based speech enhancement method, aiming at reducing non-stationary noise from speech signals. The system is based on the assumption that the speech and the noise are additive and uncorrelated. Cepstral features are used to extract statistical information from both the speech and the noise. A-priori statistical information is collected from long training sequences into ergodic hidden Markov models. Given the ergodic models for the speech and the noise, a compensated speech-noise model is created by means of parallel model combination, using a log-normal approximation. During the compensation, the mean of every mixture in the speech and noise model is stored. The stored means are then used in the enhancement process to create the most likely speech and noise power spectral distributions using the forward algorithm combined with mixture probability. The distributions are used to generate a Wiener filter for every observation. The paper includes a performance evaluation of the speech enhancer for stationary as well as non-stationary noise environment.
标签： Telecommunications Processing Signal for
上传时间： 2020-06-01
上传用户：shancjb
When 3GPP started standardizing the IMS a few years ago, most analysts expected the number of IMS deploymentsto grow dramatically as soon the initial IMS specifications were ready (3GPP Release 5 was functionallyfrozenin the first half of 2002and completedshortly after that). While those predictions have proven to be too aggressive owing to a number of upheavals hitting the ICT (Information and Communications Technologies) sector, we are now seeing more and more commercial IMS-based service offerings in the market. At the time of writing (May 2008), there are over 30 commercial IMS networks running live traffic, addingup to over10million IMS users aroundthe world; the IMS is beingdeployedglobally. In addition, there are plenty of ongoing market activities; it is estimated that over 130 IMS contracts have been awarded to all IMS manufacturers. The number of IMS users will grow substantially as these awarded contracts are launched commercially. At the same time, the number of IMS users in presently deployed networks is steadily increasing as new services are introduced and operators running these networks migrate their non-IMS users to their IMS networks.
标签： Multimedia Subsystem The IMS 3G IP
上传时间： 2020-06-01
上传用户：shancjb
The Home Gateway Initiative (HGI) is a non-profit making organization which publishes guidelines, requirements documents, white papers, vision papers, test plans and other documents concerning broadband equipment and services which are deployed in the home.
标签： Evaluation Discussion Framework Document KPI
上传时间： 2020-06-06
上传用户：shancjb
RFID (radio-frequency identification) is the use of a wireless non-contact system that uses radio-frequencyelectromagnetic fields to transfer datafrom a tag attached to an object, for the purposes of automatic identification and tracking [38]. The basic technologies for RFID have been around for a long time. Its root can be traced back to an espionage device designed in 1945 by Leon Theremin of the Soviet Union,whichretransmittedincidentradiowaves modulatedwith audioinformation. After decades of development, RFID systems have gain more and more attention from both the research community and the industry.
标签： Infrastructure RFID as an
上传时间： 2020-06-08
上传用户：shancjb
I wrote this book so that students, hobbyists, and engineers alike can take advantage of the Arduino platform by creating several projects that will teach them about the engineering process. I also wanted to guide the reader through introductory projects so that they could get a firm grasp on the Arduino Language, and how to incorporate several pieces of hardware to make their own projects. This book offers so much information on the Arduino, not just the basic LED projects but it offers different peripherals such as Ultrasonic sensor, the Xbox® controller, Bluetooth, and much more. This book also teaches the non-engineer to follow a process that will help them in future project (not just Arduino projects).
标签： Engineering Practical Arduino
上传时间： 2020-06-09
上传用户：shancjb
The main aim of this book is to present a unified, systematic description of basic and advanced problems, methods and algorithms of the modern con- trol theory considered as a foundation for the design of computer control and management systems. The scope of the book differs considerably from the topics of classical traditional control theory mainly oriented to the needs of automatic control of technical devices and technological proc- esses. Taking into account a variety of new applications, the book presents a compact and uniform description containing traditional analysis and op- timization problems for control systems as well as control problems with non-probabilistic models of uncertainty, problems of learning, intelligent, knowledge-based and operation systems – important for applications in the control of manufacturing processes, in the project management and in the control of computer systems.
上传时间： 2020-06-10
上传用户：shancjb
--stdafx.h中没有函数库，只是定义了一些环境参数，使得编译出来的程序能在32位的操作系统环境下运行。 windows和mfc的include文件都非常大，即使有一个快速的处理程序，编译程序也要花费相当长的时间来完成工作。由于每个.cpp文件都包含相同的include文件，为每个.cpp文件都重复处理这些文件就显得很傻了。 为避免这种浪费，appwizard和visualc++编译程序一起进行工作，如下所示： --appwizard建立了文件stdafx.h，该文件包含了所有当前工程文件需要的mfcinclude文件。且这一文件可以随被选择的选项而变化。 --appwizard然后就建立stdafx.cpp。这个文件通常都是一样的。 --然后appwizard就建立起工程文件，这样第一个被编译的文件就是stdafx.cpp。 --当visualc++编译stdafx.cpp文件时，它将结果保存在一个名为stdafx.pch的文件里。(扩展名pch表示预编译头文件。) --当visualc++编译随后的每个.cpp文件时，它阅读并使用它刚生成的.pch文件。visualc++不再分析windowsinclude文件，除非你又编辑了stdafx.cpp或stdafx.h。 在这个过程中你必须遵守以下规则： --你编写的任何.cpp文件都必须首先包含stdafx.h。 --如果你有工程文件里的大多数.cpp文件需要.h文件，顺便将它们加在stdafx.h(后部)上，然后预编译stdafx.cpp。 --由于.pch文件具有大量的符号信息，它是你的工程文件里最大的文件。 如果你的磁盘空间有限，你就希望能将这个你从没使用过的工程文件中的.pch文件删除。执行程序时并不需要它们，且随着工程文件的重新建立，它们也自动地重新建立。
标签： stdafx
上传时间： 2021-05-19
上传用户：1155
The PW5300 is a current mode boost DC-DC converter. Its PWM circuitry with built-in 0.2Ω powerMOSFET make this regulator highly power efficient. The internal compensation network alsominimizes as much as 6 external component counts. The non-inverting input of error amplifierconnects to a 0.6V precision reference voltage and internal soft-start function can reduce the inrushcurrent. The PW5300 is available in the SOT23-6L package and provides space-saving PCB for theapplication fields
标签： pw5300
上传时间： 2022-02-11
上传用户：jiabin
