نتایج جستجو برای: scpc

تعداد نتایج: 73  

ژورنال: :مهندسی برق مدرس 0
g.r. sowlat p. o. box: 14155-3961, tehran, iran

در شبکه ماهواره ملی که روش دسترسی scpc-dama برای آن در نظر گرفته شده، تعداد زیادی کاربر به طور همزمان از کانال مخابراتی استفاده می کنند. بنابر این مسأله تداخل بین کانالهای مجاور از اهمیت بسیاری برخوردار است. به منظور کاهش پهنای باند و تداخل بین سمبلها، پالس های داده به صورت rrc شکلدهی می شوند. تغییرات دامنه ای که در این پالسها وجود دارد، موجب تغییرات شدیدی در پوش سیگنال حامل مدوله شده و باعث ای...

2011
Masoud Motamedi

The Personal Access Satellite System (PASS) strawman design, as described in the PASS Concept Study Report, (hereafter referred to as the Strawman Design) utilizes a hybrid Time Division Multiple Access (TDMA)/ Frequency Division Multiple Access (FDMA) implementation. TDMA is used for the forward direction (from Suppliers to Users), and FDMA for the return direction (from Users to Suppliers). I...

2011
Masoud Motamedi

The Personal Access Satellite System (PASS) strawman design, as described in the PASS Concept Study Report, (hereafter referred to as the Strawman Design) utilizes a hybrid Time Division Multiple Access (TDMA)/ Frequency Division Multiple Access (FDMA) implementation. TDMA is used for the forward direction (from Suppliers to Users), and FDMA for the return direction (from Users to Suppliers). I...

2009
Nagaraj C Shivaramaiah

In heavy multipath scenarios such as urban canyons, the user code phase pseudorange error due to multipath fading can be as high as two meters even for the most sophisticated ranging signals such as Galileo E5 Alternate Binary-Offset-Carrier AltBOC (15,10). In this paper the author introduces methods to mitigate the code phase multipath by exploiting the frequency diversity which is inherent to...

Journal: :Nano letters 2012
Xinyu Xue Sihong Wang Wenxi Guo Yan Zhang Zhong Lin Wang

Energy generation and energy storage are two distinct processes that are usually accomplished using two separated units designed on the basis of different physical principles, such as piezoelectric nanogenerator and Li-ion battery; the former converts mechanical energy into electricity, and the latter stores electric energy as chemical energy. Here, we introduce a fundamental mechanism that dir...

2004
Vincent Heiries

The Binary Offset Carrier planned for future GNSS signals, including several GALILEO signals as well as GPS M-code, presents a high degree of spectral separation from conventional signals. It also greatly improves positioning accuracy and enhances multipath rejection. However, with such a modulation, the acquisition process is made more complex. Specific techniques must be employed in order to ...

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