Reduction of out of band radiation in ofdm system, Computer Networking

THE high spectral efficiency makes OFDM a suitable technology to meet the demands of wireless data traffic. A currently discussed new application are OFDM based overlay systems. In this concept, an overlay system shares the same frequency band with a licensed system by filling existing frequency gaps with OFDM subcarriers. However, OFDM suffers from high out-of-band radiation caused by sidelobes of the modulated subcarriers. Well-known techniques for sidelobe suppression are windowing the transmission (Tx) signal in time domain and the insertion of guard bands. With the former method, the symbol duration is prolonged, whereas with the latter the scarce spectral resources are wasted. Both methods reduce the system throughput and, in general, do not achieve sufficient sidelobe suppression for OFDM based overlay systems. To overcome the drawbacks of the existing techniques for sidelobe suppression we propose the concept of cancellation carriers. The basic idea is to insert a few well-defined subcarriers, referred to as cancellation carriers (CCs), at both sides of the spectrum which are weighted such that their sidelobes cancel the sidelobes of the Tx signal. In, a similar concept based on the insertion of dummy tones has been proposed for amplitude shift-keying modulation in wire line applications. However, these dummy tones are restricted to carry weighted sums of the data on other subcarriers.

 

Posted Date: 3/13/2013 6:27:17 AM | Location : United States







Related Discussions:- Reduction of out of band radiation in ofdm system, Assignment Help, Ask Question on Reduction of out of band radiation in ofdm system, Get Answer, Expert's Help, Reduction of out of band radiation in ofdm system Discussions

Write discussion on Reduction of out of band radiation in ofdm system
Your posts are moderated
Related Questions
Connectionless Multiplexing  and De multiplexing Java program running in a host can create a UDP socket  with the  line Datagram's socket my socket =  new datagram's socket

Q. What is network layer of osi model? - Describe end-to-end delivery of packets. - Defines logical addressing thus that any endpoint can be identified. - Defines how ro

Q. Show the properties of Microwaves? Microwaves - Frequencies among 1 and 300 GHz - Unidirectional - Narrow focus requires sending as well as receiving antennas to

S t d "B" 6.4 m Ku-BAND EARTH STATION (2004)   D-Sat (District Satellite Project) circuits for rural connectivity via satellite are in operation. Purpose of this project i

Draw a work breakdown structure (WBS) diagram for the project, to show all the planned tasks. This WBS should contain at least two levels. b) Explain the main differences between

a transperent switch is inserted between two local area networks ABC and XYZ.network ABC has workstation 1,2,and 3 and Network XYZ has workstation 4,5, and 6. show the contents of

Explain Fiber-Optics cable. A cable with central glass tube covered with protective shield which transmit data using photons is fiber optics cable. These cables transmit data t

Question: a) Consider the following MIP scenario. Quite a few enterprise networks use private addresses and NAPT for the communication to the Internet. i. Discu

We can deactivate advanced editing us using  terminal no editing

Question 1 Contract Net Protocol is the best known and most widely used cooperation protocol Explain how contract net works Discuss the benefits and limitations of con