نتایج جستجو برای: گیرنده rake

تعداد نتایج: 7273  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس - دانشکده برق و کامپیوتر 1391

در سیستم های طیف گسترده دنباله مستقیم (ds/cdma )، کاربران بطور همزمان از طیف فرکانسی یکسان برای ارسال سیگنال های خود استفاده می نمایند. در این روش به کاربران مختلف کدهای متمایزی اختصاص داده می شود. در کانال های چند مسیره، سیگنال دریافتی در گیرنده حاصل ترکیب نسخه های تاخیر یافته ی سیگنال اصلی است که منجر به تداخل بین سمبلی ( isi) می شود. مسئله ی آشکارسازی بهینه برای مقابله با تداخل دسترسی چندگان...

2010
J. Jeya A Celin

---------------------------------------------------------------------ABSTRACT-----------------------------------------------------------Several types of Rake Receivers like A-Rake, S-Rake, P-Rake, Adaptive frequency Rake, Time frequency Rake, Conventional MMSE Rake and Adaptive MMSE rake are used for WCDMA. In this paper we observed that the BER performance of the Adoptive MMSE Rake receiver gi...

Journal: :Aikuiskasvatus 2016

2014
Ahmed Refaat Hamad Neelesh Agrawal

Direct-sequence code-division multiple-access (DSCDMA) cellular systems, such as Wideband CDMA (WCDMA), are limited in performance by interference. Several types of Rake Receivers like A-Rake, S-Rake, P-Rake, Adaptive frequency Rake, Time frequency Rake, Conventional MMSE Rake and Adaptive MMSE rake are used for WCDMA. A Beam formerRake receiver can be an effective solution to provide the recei...

Journal: :IEICE Transactions 2005
Fumiyuki Adachi Kazuaki Takeda Hiromichi Tomeba

In this Letter, a frequency-domain pre-rake transmission is presented for a direct sequence spread spectrum with time division duplex (DSSS/TDD) system under a frequency-selective fading channel. The mathematical relationship between frequency-domain and time-domain pre-rake transmissions is discussed. It is confirmed by the computer simulation that, similar to the time-domain pre-rake transmis...

Journal: :مهندسی بیوسیستم ایران 0
مجید دهقانی دانشگاه شیراز، دانشکده کشاورزی، بخش مهندسی بیوسیستم سیدحسین کارپرورفرد هیئت علمی / دانشگاه شیراز

performance optimization of chisel tine was proposed by using a chisel plow with adjustable rake angle. effective treatments consisted of soil moisture at 0.5, 0.7 and 0.9 of plastic limit (pl), three rake angle of 30, 40 and 50 degree and speeds of to 3, 5 and 7 km h-1. the measured parameters included draft, soil disturbance area, soil upheaving area, clod mean weight diameter (mwd), specific...

2007
Taweesak Samanchuen Sawasd Tantaratana

This paper proposes noncoherent PN acquisition schemes that combine the hybrid structure, the RAKE structure, and the double/multiple-dwell technique in order to improve the performance in a frequency-selective fading channel. The hybrid structure reduces the acquisition time compared to a serial scheme. The RAKE structure enhances the received signal strength of a multipath faded signal, while...

2013
Rashid A. Fayadh F. Malek Hilal A. Fadhil Norshafinash Saudin

At receiving high data rate in ultra wideband (UWB) technology for many users, there are multiple user interference and inter-symbol interference as obstacles in the multi-path reception technique. Since the rake receivers were designed to collect many resolvable paths, even more than hundred of paths. Rake receiver implementation structures have been proposed towards increasing the complexity ...

2003
Suk Won Kim Dong Sam Ha Jeffrey H. Reed

In this paper, we investigate a new generalized selection combining (GSC) technique and an adaptive rake combining scheme to save the power consumption of mobile rake receivers for wideband CDMA systems. The new GSC technique called minimum selection GSC (MS-GSC) selects a minimum number of rake fingers, while maintaining the combined SNR larger than a given threshold. The proposed adaptive rak...

2003
J. Zhang R. A. Kennedy T. D. Abhayapala

RAKE reception for Ultra Wideband is crucial as the radiated power is restricted to be very low and there exist many resolvable multipath components. In this paper, the effectiveness of RAKE reception is investigated analytically. First, the conditions under which the interference in the RAKE fingers can be ignored are discussed. Then a method is introduced to derive the explicit expression of ...

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