The new digital radio system DAB (Digital Audio Broadcasting, nowadays often called Digital Radio) is a very innovative and universal multimedia broadcast system which will replace the existing AM and FM audio broadcast services in many parts of the world in the future. It was developed in the 1990s by the Eureka 147/DAB project. DAB is very well suited for mobile reception and provides very high robustness against multipath reception. It allows use of single frequency networks (SFNs) for high frequency efficiency.
標簽： Broadcasting Principles Digital Audio
上傳時間： 2020-05-27
上傳用戶：shancjb
Optical communication technology has been extensively developed over the last 50 years, since the proposed idea by Kao and Hockham [1]. However, only during the last 15 years have the concepts of communication foundation, that is, the modulation and demodulation techniques, been applied. This is pos- sible due to processing signals using real and imaginary components in the baseband in the digital domain. The baseband signals can be recovered from the optical passband region using polarization and phase diversity tech- niques, as well as technology that was developed in the mid-1980s.
標簽： Transmission Processing Digital Optical
上傳時間： 2020-05-27
上傳用戶：shancjb
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
The first Third Generation Partnership Project (3GPP) Wideband Code Division Multiple Access (WCDMA) networks were launched during 2002. By the end of 2005 there were 100 open WCDMA networks and a total of over 150 operators having frequency licenses for WCDMA operation. Currently, the WCDMA networks are deployedinUniversalMobileTelecommunicationsSystem(UMTS)bandaround2GHz in Europe and Asia including Japan and Korea. WCDMA in America is deployed in the existing 850 and 1900 spectrum allocations while the new 3G band at 1700/2100 is expected to be available in the near future. 3GPP has defined the WCDMA operation also for several additional bands, which are expected to be taken into use during the coming years.
標簽： HSDPAHSUPA Access Speed Radio UMTS High for
上傳時間： 2020-05-27
上傳用戶：shancjb
This research work aims at eliminating the off-chip RF SAW filters from fre- quency division duplexed (FDD) receivers. In the first approach, a monolithic passive RF filter was constructed using on-chip capacitors and bondwire inductors. The bond- wire characteristics were studied in details and the effect of mutual inductive coupling between the bondwires on the filter performance was analyzed. Based on that, a bond- wire configuration was proposed to improve the frequency response of the filter. The filter was implemented in 0.18 μm CMOS process for WCDMA applications.
標簽： Interference Mitigation Techniques
上傳時間： 2020-05-27
上傳用戶：shancjb
Radio frequency (RF) power amplifiers are used in everyday life for many applica- tions including cellular phones, magnetic resonance imaging, semiconductor wafer processing for chip manufacturing, etc. Therefore, the design and performance of RF amplifiers carry great importance for the proper functionality of these devices. Furthermore, several industrial and military applications require low-profile yet high-powered and efficient power amplifiers.
標簽： Introduction Amplifier Design Power to RF
上傳時間： 2020-05-27
上傳用戶：shancjb
With the rapid expansion of wireless consumer products,there has been a con- siderable increase in the need for radio-frequency (RF) planning, link plan- ning, and propagation modeling.A network designer with no RF background may find himself/herself designing a wireless network. A wide array of RF planning software packages can provide some support, but there is no substi- tute for a fundamental understanding of the propagation process and the lim- itations of the models employed. Blind use of computer-aided design (CAD) programs with no understanding of the physical fundamentals underlying the process can be a recipe for disaster. Having witnessed the results of this approach, I hope to spare others this frustration.
標簽： Introduction Propagation to RF
上傳時間： 2020-05-27
上傳用戶：shancjb
To meet the future demand for huge traffic volume of wireless data service, the research on the fifth generation (5G) mobile communication systems has been undertaken in recent years. It is expected that the spectral and energy efficiencies in 5G mobile communication systems should be ten-fold higher than the ones in the fourth generation (4G) mobile communication systems. Therefore, it is important to further exploit the potential of spatial multiplexing of multiple antennas. In the last twenty years, multiple-input multiple-output (MIMO) antenna techniques have been considered as the key techniques to increase the capacity of wireless communication systems. When a large-scale antenna array (which is also called massive MIMO) is equipped in a base-station, or a large number of distributed antennas (which is also called large-scale distributed MIMO) are deployed, the spectral and energy efficiencies can be further improved by using spatial domain multiple access. This paper provides an overview of massive MIMO and large-scale distributed MIMO systems, including spectral efficiency analysis, channel state information (CSI) acquisition, wireless transmission technology, and resource allocation.
標簽： Large-scale Antenna Systems
上傳時間： 2020-05-27
上傳用戶：shancjb
Nature is seldom kind. One of the most appealing uses for radio- telephone systems—communication with people on the move—must over- come radio transmission problems so difficult they challenge the imagina- tion. A microwave radio signal transmitted between a fixed base station and a moving vehicle in a typical urban environment exhibits extreme variations in both amplitude and apparent frequency.
標簽： Communications Microwave Mobile
上傳時間： 2020-05-28
上傳用戶：shancjb
Multi-carrier modulation? Orthogonal Frequency Division Multi- plexing (OFDM) particularly? has been successfully applied to a wide variety of digital communications applications over the past several years. Although OFDM has been chosen as the physical layer standard for a diversity of important systems? the theory? algorithms? and implementation techniques remain subjects of current interest. This is clear from the high volume of papers appearing in technical journals and conferences.
標簽： COMMUNICATIONS MULTI-CARRIER DIGITAL
上傳時間： 2020-05-31
上傳用戶：shancjb
