Orthogonal Frequency Division Multiple Access (OFDMA) is a multiple access scheme for OFDM systems. It works by assigning a subset of subcarriers to individual users.



OFDMA features

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OFDMA is the 'multi-user' version of OFDM
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Functions by partitioning the resources in the time-frequency space, by assigning units along the OFDM signal index and OFDM sub-carrier index
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Each OFDMA user transmits symbols using sub-carriers that remain orthogonal to those of other users
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More than one sub-carrier can be ....etc

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Overview
Code division multiple access (CDMA) is a modulation and multiple-access scheme based on spread-spectrum communication. In this scheme, multiple users share the same frequency band at the same time, by spreading the spectrum of their transmitted signals, so that each user's signal is pseudo-orthogonal to the signals of the other users.

CDMA Signals
In a CDMA system, each signal consists of a different pseudorandom binary sequence (called the spreading code) that modulates a carrier, spreading the spectrum of the waveform. A large ....etc

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Hi,
visit these threads for your topic:
http://seminarsprojects.net/Thread-cdma-technology-ppt
http://seminarsprojects.net/Thread-wirelss-technology-full-report
http://seminarsprojects.net/Thread-Distributed-Medium-Access-Control-for-Next-Generation-CDMA-Wireless-Networks-seminars
http://seminarsprojects.net/Thread-CDMA-Wireless-Data-Transmitter-Seminar-Report ....etc

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To get full information or details of space division multiple access please have a look on the pages

http://seminarsprojects.net/Thread-code-division-multiple-access-cdma

if you again feel trouble on space division multiple access please reply in that page and ask specific fields in space division multiple access ....etc

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TDMA, or Time Division Multiple Access was one of the first cell phone digital standards available in the United States. It was the first successor to the original AMPS analog service that was popular throughout the country, and was in popular service from the early-mid 1990's up until roughly 2003 when the last of the TDMA carriers, Cingular and AT&T, switched to the GSM digital standard.

TDMA was a significant leap over the analog wireless service that was in place at the time, and it's chief benefit for carriers was that it used the avail ....etc

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Abstract:
Orthogonal Frequency-Division Multiple Access (OFDMA) is a multi-user version. Multiple access is achieved in OFDMA by assigning subsets of subcarriers to individual users. This allows simultaneous low data rate transmission from several users, OFDM is sometimes referred to as discrete multi-tone modulation, instead of a single carrier being modulated, a large number of evenly spaced subcarriers are modulated using some m-ary of QAM. This is a spread-spectrum technique that increases the efficiency of data communications by increasin ....etc

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Abstract
The ordinary CDMA technology has the disadvantage of identifying the users using the appropriate signature of each user. Since many users tend to use the transmission media, there is always a chance for superimposition of signals that can cause interference in network.

The solution for this inconvenience comes in the form of interleaving which separates the users. This special form of CDMA technology offers some of the features of CDMA such as the dynamic channel sharing, mitigation of cross cell reference, asynchronous tran ....etc

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Presented By:-
Siddhartha Panda


INTRODUCTION
WCDMA stands for Wide Band Code Division Multiple Access.
W-CDMA is a Third-Generation(3G) mobile wireless technology that promises much higher data speeds to mobile and portable wireless devices than commonly offered in today's market.
It is specified by 3rd Generation Partnership Project (3GPP).
It is the key technology for UMTS.
HISTORY
QUALCOMM , the first company to succeed in developing a practical and cost effective CDMA implementation for co ....etc

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h friend you can refer these pages to get the details on wide band code division multiple access

http://seminarsprojects.net/Thread-w-cdma-wideband-code-division-multiple-access

http://seminarsprojects.net/Thread-w-cdma-wideband-code-division-multiple-access?pid=5414#pid5414 ....etc

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IMPLEMENTATION OF PRECODING FOR SC-FDMA SYSTEMS
Presented by
VISHNUPRIYA L
M3 MTV,
CET ,TRIVANDRUM



CONTENTS
INTRODUCTION
MOTIVATION
LITERATURE REVIEW
BLOCK DIAGRAM
WORK DONE
FUTURE WORKS

ABSTRACT
Single Carrier Frequency Division Multiple Access (SC-FDMA) is a technique for high data rate uplink transmission in cellular technology. It satisfies the demand of requiring higher data rate. This requirement of high data rate results in significant ....etc

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