-
The design and manufacturing of wireless radio frequency (RF) transceivers has developed rapidly in recent ten
yeas due to rapid development of RF integrated circuits and the evolution of high-speed digital signal
processors (DSP). Such high speed signal processors, in conjunction with the development of high resolution
analog to digital converters and digital to analog converters, has made it possible for RF designers to digitize
higher intermediate frequencies, thus reducing the RF section and enhancing the overall performance of the RF
section.
標簽：
Transceivers
Wireless
Digital
上傳時間：
2020-05-27
上傳用戶：shancjb
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The General Packet Radio Service (GPRS) allows an end user to send and
receive data in packet transfer mode within a public land mobile network
(PLMN) without using a permanent connection between the mobile station
(MS) and the external network during data transfer. This way, GPRS opti-
mizes the use of network and radio resources (RRs) since, unlike circuit-
switched mode, no connection between the MS and the external network is
established when there is no data flow in progress. thus, this RR optimiza-
tion makes it possible for the operator to offer more attractive fees.
標簽：
Mobile
EDGE
上傳時間：
2020-05-27
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In cellular networks, it is estimated that
2
3
of calls and over 90% of data services occur
indoors. However, some surveys show that many households and businesses experience
a poor indoor coverage problem. It has been identified that poor coverage is the main
reason for churn, which is very costly for operators in saturated markets. How to provide
good indoor coverage cost effectively is thus a demanding challenge for operators.
標簽：
Technologies
Femtocells
Deployment
and
上傳時間：
2020-05-27
上傳用戶：shancjb
-
Providing QoS while optimizing the LTE network in a cost efficient manner is
very challenging. thus, radio scheduling is one of the most important functions
in mobile broadband networks. The design of a mobile network radio scheduler
holds several objectives that need to be satisfied, for example: the scheduler needs
to maximize the radio performance by efficiently distributing the limited radio re-
sources, since the operator’s revenue depends on it.
標簽：
Communications
Future
Mobile
LTE
上傳時間：
2020-05-27
上傳用戶：shancjb
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Ever since ancient times, people continuously have devised new techniques and
technologies for communicating their ideas, needs, and desires to others. thus,
many forms of increasingly complex communication systems have appeared
over the years. The basic motivations behind each new one were to improve the
transmission fidelity so that fewer errors occur in the received message, to
increase the transmission capacity of a communication link so that more infor-
mation could be sent, or to increase the transmission distance between relay sta-
tions so that messages can be sent farther without the need to restore the signal
fidelity periodically along its path.
標簽：
Communications
Essentials
Optical
上傳時間：
2020-05-31
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Wireless communications has become a field of enormous scientific and economic interest. Recent
success stories include 2G and 3G cellular voice and data services (e.g., GSM and UMTS), wireless
local area networks (WiFi/IEEE 802.11x), wireless broadband access (WiMAX/IEEE 802.16x), and
digital broadcast systems (DVB, DAB, DRM). On the physical layer side, traditional designs typically
assume that the radio channel remains constant for the duration of a data block. However, researchers
and system designers are increasingly shifting their attention to channels that may vary within a block.
In addition to time dispersion caused by multipath propagation, these rapidly time-varying channels
feature frequency dispersion resulting from the Doppler effect. They are, thus, often referred to as
being “doubly dispersive.”
標簽：
Time-Varying
Channels
上傳時間：
2020-06-01
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In this book we focus on the basic signal processing that underlies current and
future ultra wideband systems. By looking at signal processing in this way we
hope this text will be useful even as UWB applications mature and change or
regulations regarding ultra wideband systems are modified. The current UWB
field is extremely dynamic, with new techniques and ideas being presented at every
communications and signal-processing conference. The basic signal-processing
techniques presented in this text though will not change for some time to come.
thus, we have taken a somewhat theoretical approach, which we believe is longer
lasting and more useful to the reader in the long term than an up-to-the-minute
summary that is out of date as soon as it is published.
標簽：
Wideband
Signals
Systems
Ultra
1st
上傳時間：
2020-06-01
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A wireless ad-hoc network is a wireless network deployed without any infrastructure. In
such a network, there is no access point or wireless router to forward messages among the
computing devices. Instead, these devices depend on the ad-hoc mode of their wireless net‐
work interface cards to communicate with each other. If the nodes are within the transmis‐
sion range of the wireless signal, they can send messages to each other directly. Otherwise,
the nodes in between will forward the messages for them. thus, each node is both an end
system and a router simultaneously.
標簽：
WIRELESS
NETWORKS
AD-HOC
上傳時間：
2020-06-01
上傳用戶：shancjb
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This effort started as an answer to the numerous questions the authors have
repeatedly had to answer about electrostatic discharge (ESD) protection and
input/output (1/0) designs. In the past no comprehensive book existed suffi-
ciently covering these areas, and these topics were rarely taught in engineering
schools. thus first-time I/O and ESD protection designers have had consider-
able trouble getting started. This book is in part an answer to such needs.
標簽：
Design
Basic
ESD
and
IO
上傳時間：
2020-06-05
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GaN is an already well implanted semiconductor
technology, widely diffused in the LED optoelectronics
industry. For about 10 years, GaN devices have also been
developed for RF wireless applications where they can
replace Silicon transistors in some selected systems. That
incursion in the RF field has open the door to the power
switching capability in the lower frequency range and
thus to the power electronic applications.
Compared to Silicon, GaN exhibits largely better figures
for most of the key specifications: Electric field, energy
gap, electron mobility and melting point. Intrinsically,
GaN could offer better performance than Silicon in
terms of: breakdown voltage, switching frequency and
Overall systems efficiency.
標簽：
GaN-on-Si
Displace
and
SiC
Si
上傳時間：
2020-06-07
上傳用戶：shancjb
