Orthogonal Frequency Division Multiplexing


1. INTRODUCTION
1.1. Introduction:-
Orthogonal Frequency Division Multiplexing (OFDM) is one of the latest modulation techniques used in order to combat the frequency-selectivity of the transmission channels, achieving high data rate without inter–symbol interference. The basic principle of OFDM is gaining a wide spread popularity within the wireless transmission community. Furthermore,
OFDM is one of the main techniques proposed to be employed i ....etc

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A Technique for Orthogonal Frequency Division Multiplexing
Frequency Offset Correction

Abstract:
The Orthogonal Frequency Division Multiplexing (OFDM) is a Multi Carrier Modulation technique employing Frequency Division Multiplexing of orthogonal subcarriers. It is also sometimes called as discrete multitone modulation (DMT). It is better than CDMA in high bit rate and Broadband Communications .It is a multi carrier technique, which is very sensitive to Frequency Offset between transmitter and receiver. Th ....etc

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This paper deals with the twin concepts of optical networking and dense wavelength division multiplexing. The paper talks about the various optical network architectures and the various components of an all-optical network like Optical Amplifiers, Optical Add/Drop Multiplexers, Optical Splitters etc. Important optical networking concepts like wavelength routing and wavelength conversion are explained in detail. Finally this paper deals with industry related issues like the gap between research and the industry, current and projected market for ....etc

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PRESENTED BY:
Mustafa Ashurex,
Scott Hansen


Overview
Multiplexing is sending multiple signals or streams of data on an information line at the same time in the form of a single, more complex signal and then separating the signals at the receiving end.
Inverse Multiplexing is combining multiple low speed streams of data to form a single higher-speed data stream. The sending and receiving ends use an inverse multiplexer with one high speed input stream.
Analog Transmission
Each signal is assig ....etc

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tell about Stastistical TDM with Diagram
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Orthogonal Frequency Division Multiplexing (OFDM)



ABSTRACT
Orthogonal Frequency Division Multiplexing (OFDM) has recently gained a lot of attention and is a promising candidate for future wireless multimedia communications due to it is resistive to frequency-selective fading and its flexibility for handling multiple data rates for Fourth Generation (4G) wireless systems also it promises data rates up to 10Mbps. A variation of OFDM is Multi-Carrier CDMA (MC-CDMA), in which ....etc

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Definition

Multi Carrier Modulation is a technique for data transmission by dividing a high ]bit rate data stream is several parallel low bit ]rate data streams and using these low bit rate data streams to modulate several carriers. Multi Carrier Transmission has a lot of useful properties such as delay spread tolerance and spectrum efficiency that encourage their use in untethered broadband communications. OFDM is a multi carrier modulation technique with densely spaced sub carriers that has gained a lot of popularity among the bro ....etc

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ABSTRACT:

OFDM
otherwise called orthogonal frequency division multiplexing is a modulation and a multiple access technique that can be applied to mobile communications.
OFDM or Multitone modulation as it is sometimes called is the basis for several commercial wireless applications. In OFDM the segments are according to frequency there by dividing the spectrum into a number of equally spaced tones, which are orthogonal with each other and carries a portion of user information ....etc

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The technology of combining a number of optical wavelengths and then transmitting the same through a single fibre is called wavelength division multiplexing (WDM). Conceptually, the technology is similar to that of frequency division multiplexing (FDM) used in analogue transmission. Dense wavelength division multiplexing (DWDM) is anew born multiplexing technology in the fibre optic transmission, bringing about a revolution in the bit rate carrying capacity over a single fibre. The emergent of DWDM system is one of the important phenomena in de ....etc

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In a WDM system, each of the wavelengths is launched into the fiber, and the signals are demultiplexed at the receiving end. Like TDM, the resulting capacity is an aggregate of the input signals, but WDM carries each input signal independently of the others. This means that each channel has its own dedicated bandwidth; all signals arrive at the same time, rather than being broken up and carried in time slots. The difference between WDM and dense wavelength division multiplexing (DWDM) is fundamentally than does WDM, and therefore has a greater ....etc

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