نتایج جستجو برای: سیستم ofdma
تعداد نتایج: 75838 فیلتر نتایج به سال:
In the growth of fourth-generation mobile servicing, long` c ns term evolution (LTE) is an emanate technology. In LTE the downlink model build up on orthogonal frequency division multiple access (OFDMA) and the uplink arrangement build up on single carrier frequency division multiple access (SC-FDMA).In this paper we have tendency to derive the achievement of typical elemental differences betwe...
نسل آینده سیستم های مخابرات بی سیم به منظور پاسخ گویی به خدمات نرخ داده بالا و متنوع مانند انتقال صدا، ویدئو و غیره طراحی شده است که مصرف انرژی بالایی را ایجاد می کند. به دلیل منابع باتری محدود شده در پایانه های تلفن همراه و نیز هزینه عملیاتی بالای مصرف انرژی در ایستگاه های پایه، ضرورت ذخیره سازی انرژی و رسیدن به بازدهی انرژی بالا در نسل آینده شبکه های بی سیم ضروری است. تاکنون تلاش های زیادی بر...
Orthogonal Frequency-Division Multiple Access (OFDMA) is a multi-user version of the Orthogonal frequency-division multiplexing (OFDM). OFDMA is used in the mobility mode of IEEE 802.16 WirelessMAN Air Interface standard, commonly referred to as WiMAX. Multiple access is achieved in OFDMA by assigning subsets of subcarriers to individual users [1], [2]. The performance of these systems depend o...
Long Term Evolution (LTE) is consents pliable spectrum distribution which renders enriched wireless data services to users at lower latency and multi-megabit throughput. LTE uses Orthogonal Frequency Division Multiple Access (OFDMA) and Single Carrier Frequency Division Multiple Access (Sc-FDMA) for downlink and Uplink transmission where OFDMA has been acquired in LTE for downlink transmission ...
Worldwide interoperability for Microwave Access (WiMAX) is a Broad Band Wireless Access (BWA) technology. It provides high data rates and multimedia services. It also supports Quality of Services (QoS) for various types of application. When large number of users use these application, the OFDMA is used to divide the channel into several subchannels and those subchannel can be provided for diffe...
Orthogonal Frequency-Division Multiple Access (OFDMA) systems have attracted considerable attention through technologies such as 3GPP Long Term Evolution (LTE) and Worldwide Interoperability for Microwave Access (WiMAX). OFDMA is a flexible multiple-access technique that can accommodate many users with widely varying applications, data rates, and Quality of Service (QoS) requirements. OFDMA has...
In this paper, we consider the frequency offset estimation for Orthogonal Frequency-Division Multiple Access (OFDMA) uplink (UL) transmissions. We first analyze the negative effect of Multi-Access-Interference (MAI) on OFDMA UL, and then propose two interference reduction/elimination methods, i.e., the Reduced-Rank-Projector (RRP) and Shift-Sampling-Projector (SSP) methods, to eliminate/reduce ...
© 2014 Yonghoon Choi 953 http://dx.doi.org/10.4218/etrij.14.0113.0843 This paper studies the uplink resource allocation for multiple radio access (MRA) in reconfigurable radio systems, where multiple-input and multiple-output (MIMO) multicarrier-code division multiple access (MCCDMA) and MIMO orthogonal frequency-division multiple access (OFDMA) networks coexist. By assuming multi-radio user eq...
Abstract — This paper analyzes the performance of an orthogonal frequencydivision multiple access (OFDMA) scheme in which the carriers assigned to a user are uniformly spaced across the channel bandwidth and code-division multiplexing is used between them. Zero forcing and minimum mean-square error equalization and maximum-likelihood detection are used to compensate for multipath fading. It is ...
We investigate the sensitivity to carrier phase jitter of an orthogonal frequency-division multiple access (OFDMA) system. When all OFDMA carriers have the same power level and the jitter spectrum, the degradation caused by the jitter is shown to be equal to the degradation of an OFDM system. Also, traditional FDMA is found to be slightly more robust than OFDMA. I. System description. Orthogona...
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