نتایج جستجو برای: پالس uwb

تعداد نتایج: 6863  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت دبیر شهید رجایی - دانشکده مهندسی برق و کامپیوتر 1392

مسأله همزمانی یکی از چالش های اساسی در هر گیرنده مخابراتی به ویژه در سیستم های فراپهن باند است. تاخیر به وجود آمده در کانال انتشار، منجر به ایجاد تداخل بین سمبلی می شود که به نوبه خود عملکرد سیستم را تحت تأثیر قرار می دهد. از این رو در آغاز کار، ابتدا روش های همزمانی متداول از قبیل همزمانی با الگوی کثیف و همزمانی با استفاده از گیرنده آشکارساز انرژی بررسی و ارزیابی شده است. در این پایان نامه ب...

2005
Shing TenqChen Ying-Haw Shu Ming-Chang Sun Wu-Shiung Feng Chao-Hao Lee

In this paper, the performance comparison of PPM-TH, PAM-TH, and PAM-DS UWB for a single user link are analyzed for different data rates using the proposed UWB channel model from IEEE 802.15.3a. The Rake receivers with a pulse-matched filter via correlation mask are numerically evaluated with channel estimator algorithm. DS-UWB and TH-UWB with antipodal modulation perform basically the same. Ho...

2010
Eng Gee Lim Zhao Wang Chi-Un Lei Yuanzhe Wang

Since the release by the Federal Communications Commission (FCC) of a bandwidth of 7.5GHz (from 3.1GHz to 10.6GHz) for ultra wideband (UWB) wireless communications, UWB is rapidly advancing as a high data rate wireless communication technology. As is the case in conventional wireless communication systems, an antenna also plays a very crucial role in UWB systems. However, there are more challen...

Journal: :CoRR 2013
Sheng Jiang Matthew Trinkle Hongyuan Wang

Millimeter-accuracy Ultra-Wideband (UWB) positioning systems using the Time Difference Of Arrival (TDOA) algorithm are able to be utilized in military and many other important applications. Previous research on UWB positioning system has achieved up to mm or sub-mm accuracy. However, one bottleneck in UWB system is at sampling high resolution UWB signals, as well as high resolution timing infor...

Journal: :EURASIP J. Wireless Comm. and Networking 2005
Jinho Choi

Recently, ultra-wideband (UWB) technology, which uses a very short pulse for wireless digital communications, has been extensively investigated due to its significance that enables to transmit data sequences at a very high rate. Although the propagation range of UWB signals is short (about ten meters [1]), its impact on wireless home networks can be quite significant. Apart from the support of ...

2005
Bazil TAHA-AHMED Miguel CALVO-RAMÓN Leandro de HARO-ARIET

The effect of UWB interference on the DCS-1800 and GSM-900 downlink is studied for different UWB power density. For high UWB power density (-70 dBm/MHz), the effect of UWB signals is very high when the distance between UWB transmitter and DCS-1800 receiver is less than 1 m. For low UWB power density (-100 dBm/MHz), the effect of the UWB signals is quasi null even if the distance between the UWB...

2013
M. S. I. M. Zin A. A. M. Isa M. S. M. Isa

In this paper, we consider the possibility of developing an optimal medium access control (MAC) layer for high data rate ultra-wideband (UWB) transmission systems that transmit minimal power. MAC in UWB wireless networks is required to coordinate channel access among competing devices. The unique UWB characteristics offer great challenges and opportunities in effective UWB MAC design. We first ...

2013
Sheng Jiang Matthew Trinkle Hongyuan Wang

Millimeter-accuracy Ultra-Wideband (UWB) positioning systems using the Time Difference Of Arrival (TDOA) algorithm are able to be utilized in military and many other important applications. Previous research on UWB positioning system has achieved up to mm or sub-mm accuracy. However, one bottleneck in UWB system is at sampling high resolution UWB signals, as well as high resolution timing infor...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی خواجه نصیرالدین طوسی - دانشکده مهندسی برق و کامپیوتر 1391

هدف این پروژه طراحی و ساخت پروب میدان های پالسی و توسعه آن برای استفاده در رادارهای پلاریمتریک uwb است. پالس مبنا برای طراحی پروب، دوبلت گوسی با طول یک نانو ثانیه می باشد. آنتن دوقطبی کوچک به عنوان سنسور d-dot کاملا شناخته شده است. طول موثر آن رزنانسی است و خروجی آن، به علت امپدانس ورودی خازنی، متناسب با مشتق اول زمانی میدان الکتریکی است . در این پروژه از آنتن دوقطبی کوچک مایکرواستریپ استفاده ش...

Journal: :Journal of physics 2023

Abstract Ultra wideband (UWB) communication technology is a that uses very short time scale to transmit information. It has the advantages of high transmission rate, low power consumption, and good privacy. In this paper, basic principle UWB briefly described, several common technologies are emphatically expounded, characteristics each their disadvantages compared. At same time, article focuses...

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