Orthogonal Frequency Division Multiplexing (OFDM)
Journal Title: International Journal for Research in Applied Science and Engineering Technology (IJRASET) - Year 2015, Vol 3, Issue 5
Abstract
Orthogonal frequency-division multiplexing (OFDM) is a method of encoding digital data on multiple carrier frequencies. OFDM has developed into a popular scheme for wideband digital communication, whether wireless or over copper wires, used in applications such as digital television and audio broadcasting, DSL Internet access, wireless networks, power line networks, and 4G mobile communications. OFDM is a frequency-division multiplexing (FDM) scheme used as a digital multi-carrier modulation method. A large number of closely spaced orthogonal sub-carrier signals are used to carry data on several parallel data streams or channels. The orthogonality allows high spectral efficiency, with a total symbol rate near the Nyquist rate for the equivalent baseband signal (i.e. near half the Nyquist rate for the double-side band physical passband signal). Almost the whole available frequency band can be utilized. OFDM generally has a nearly 'white' spectrum, giving it benign electromagnetic interference properties with respect to other cochannel users. The primary advantage of OFDM over single-carrier schemes is its ability to cope with severe channel conditions (for example, attenuation of high frequencies in a long copper wire, narrowband interference and frequencyselective fading due to multipath) without complex equalization filters. In OFDM, the sub-carrier frequencies are chosen so that the sub-carriers are orthogonal to each other, meaning that cross-talk between the sub-channels is eliminated and inter-carrier guard bands are not required. This greatly simplifies the design of both the transmitter and the receiver; unlike conventional FDM, a separate filter for each sub-channel is not required.
Authors and Affiliations
Prof. S. G. Anantwar, Miss. Vaishnavi Sarad
Keywords
Related Articles
- EP ID EP20338
- DOI -
- Views 219
- Downloads 5
A Study On Financial Performance Of Cement Companies In India With Reference to Ultratech Cement Limited and OCL India Limited - A Comparative Analysis
India is the second largest producer of cement in the world. Cement production increased at a compound annual growth rate (CAGR) of 9.7 per cent in the period 2006– 2013, producing 272 million tonnes (MT). In this study...
Estimation of Application Maintenance cost using COCOMO81
Constructive Cost Model is one of the CE models which contribute three different models namely basic, intermediate and detailed model. Maintenance of software is very much important so as to increase the functionality o...
Savoir-faire malware tracking down in Delay Tolerant Networks
With the universal presence of short-range connectivity technologies (e.g., Bluetooth and, more recently, Wi-Fi Direct) in the consumer electronics market, the delay tolerant-network (DTN) model is becoming a viable alt...
Design of Novel Bridgeless AC-DC-AC Fly Back Convertor using Matlab
The aim of the project is to design and analyse of an AC-DC-AC fly back convertor without the usage of bridge circuit. Comparison of basic bridge diode circuit, which the flyback rectifier with a bridgeless topology can...
Improved Honey Bee inspired load balancing of tasks with position updation
Load balancing is an important aspect of cloud computing. To achieve optimal machine utilization, tasks from overloaded virtual machines should be transferred to under loaded virtual machines. In this paper, the honey b...