نتایج جستجو برای: cdma تخصیص توان

تعداد نتایج: 110620  

1993
Philip K. McKinley Christian Trefftz

This paper describes a CSIM-based simulation tool, called MultiSim, which allows eecient simulation of large-scale mul-tiprocessors. Methods are described for simulating several variations of wormhole routing, including multicast communication , the use of variable-sized buuers at routers within the network, and the use of virtual channels. The key to eecient simulation of such networks is that...

2003
Vitor Rocha de Carvalho Celso de Almeida Eduardo Nisenbaum

Code Division Multiple Access (or CDMA) is a multiple access technique based on spectral spreading that has been tremendously successful in the wireless domain. The effectiveness of CDMA in applications like cellular networks, satellite systems and Wireless Local Loop systems has strongly contributed to maintaining the application of CDMA to the optical domain, also known as Optical CDMA, an ac...

2001
Chi-Chung Chen Kung Yao Ken Umeno Ezio Biglieri

A new-design methodology for the design of optimal spread-spectrum sequences for asynchronous code-division multiple acces (A-CDMA) and chip-synchronous CDMA (CS-CDMA) systems is proposed. We derive general results on the partial auto-correlation function of the optimal spreading sequences for CS-CDMA and A-CDMA systems with respect to the minimization of the average bit error rate under the st...

Journal: :IEICE Transactions 2005
Young-Hwan You Min-goo Kang Han-Jong Kim Pan-Yuh Joo Hyoung-Kyu Song

One of the main disadvantage of multi-carrier CDMA (MC-CDMA) signals is the high peak power of the transmitted signals which limits their applications. To account for this issue, we provide a simple signal processing for reducing the high crest factor (CF) of MC-CDMA signals. Using this modified MC-CDMA signal, the high CF due to Walsh spreading sequences can be mitigated without explicit side ...

2012
B. Alekya J. Ravindrababu D. Swathi V. Krishna Rao

The 3 generation mobile communication system will base on Code Division Multiple Access (CDMA) system, because CDMA system can provide more capacity than TDMA and FDMA systems. But signal will suffer from the interference called Multiple Access Interference (MAI).This problem can be reduced by using multi-user detection technique. This paper examines the Performance of Parallel Interference Can...

2006
Zhenning Shi Christian Schlegel Roland Kempter Mark C. Reed

In this paper, we investigate the performance of a recently proposed multiple-access system, namely, partitionspreading CDMA (PS-CDMA). We show via variance evolution that the asymptotic channel throughput of PS-CDMA improves monotonically as the number of partitions increases. The fundamental limit of the PS-CDMA system is calculated by evaluating the spectral efficiency of the layered channel...

Journal: :CoRR 2010
Nam Yul Yu

Reed-Muller codes are studied for peak power control in multicarrier code-division multiple access (MC-CDMA) communication systems. In a coded MC-CDMA system, the information data multiplexed from users is encoded by a Reed-Muller subcode and the codeword is fully-loaded to Walsh-Hadamard spreading sequences. The polynomial representation of a coded MC-CDMA signal is established for theoretical...

1996
Yash M. Vasavada Jeffrey H. Reed Dennis G. Sweeney Milap Majmundar Nitin Mangalvedhe Paul Petrus

Analog frequency modulated (FM) systems offer advantages of reliable speech quality and simplicity, whereas code division multiple access (CDMA) systems promise high capacity, resistance to multipath fading, and simplified frequency planning. In this thesis, we investigate the performance of a wireless local loop (WLL) system that uses the frequency modulation with the CDMA technique. The perfo...

ژورنال: :کیفیت و بهره وری صنعت برق ایران 0
امیر خالدیان amir khaledian مسعود علی اکبر گلکار masoud aliakbar golkar

در این مقاله، الگوی جدیدی از تخصیص توان بین منابع تولید پراکنده در ریزشبکه جزیره ای ارائه می شود. با توجه به وجود منابع دارای تاخیر در تولید توان نظیر پیل سوختی، با استفاده از ساختار کنترل توان معرفی شده می­ توان توانایی ریزشبکه برای مواجهه با انواع سناریوهای تغییر بار را افزایش داد. روش جدید نیاز به بکارگیری از ذخیره­ سازهای انرژی نظیر باتری­ ها و سوپرخازن­ ها در کنار منابع دارای تاخیر زمانی د...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس 1388

در این رساله، یک روش پیش کدینگ چندکاربره برای سیستمهای چندحاملی cdma با استفاده از الگوریتم em ارائه می شود. فرمول بندی، مراحل پیاده سازی و مرتبه پیچیدگی این پیش کدینگ به صورت تحلیلی ارائه می شود و کارآیی آن روی کانال محوشونده رایلی مورد بررسی قرار می گیرد. همچنین کارآیی روش پیشنهادی با کارآیی سایر روشهای پیش کدینگ که قبلاً در سیستمهای چندحاملی cdma پیاده سازی شده اند، مقایسه می شود. نتایج بررسی...

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