Orthogonal frequency division multiplexing, Electrical Engineering

Assignment Help:

CURRENTLY, orthogonal frequency division multiplexing (OFDM) is emerging as the preferred modulation technique in modern high data rate broadband wireless mobile communication systems. In OFDM, the entire spectrum is divided into subcarriers which are narrow-banded with respec to the coherence bandwidth of the channel. This provides resistance against frequency-selectivity of the channel for wideband data transmission. However, the well known problem in OFDM system is its vulnerability to the frequency offset errors causedby oscillator inaccuracies or the Doppler frequency shift due to mobility. In high mobility scenarios, the orthogonality of the subcarriers is no longer maintained that results in inter-carrier interference (ICI). Hence, the transmission performance of the mobile OFDM system is degraded severely.

ICI cancellation techniques are essential in improving the per formance of OFDM system in an environment which induces frequency offset error. A lot of ICI mitigation methods have been extensively investigated to combat the ICI, including fre- quency-domain equalization, time-domain windowing and the self-cancellation schemes, frequency offset estimation and tracking techniques and so on. Among the methods, the ICI self-cancellation method is a simple way to suppress ICI that uses redundant modulation. Several selfcancellation methods have been exploited, including data conversion, data conjugate and symmetric data-conversion/conjugate methods. Windowing methods reduce the SNR but they need redundant information. That is, the performances of the windowing methods and self-cancellation methods degrade signi?cantly with the increase of frequency offset. Besides, maximum likelihood estimation and extended Kalman


Related Discussions:- Orthogonal frequency division multiplexing

Evaluate the thickness of the shell plate, A cylindrical shell with flat en...

A cylindrical shell with flat ends is of 1.5 m Internal diameter and 4 m length. It is subjected to an internal pressure of 300 N/cm 2 . The principal stress is not to exceed 15 K

Explain public mode, Explain PUBLIC For large programs several small mo...

Explain PUBLIC For large programs several small modules are linked together. In order that the modules link together correctly any variable name or label referred to in other m

Calculate the power required from power plant, You will develop a simulatio...

You will develop a simulation that will consist of the following five components: Controller: This script component controls the simulation. It shall permit the user to: 1. C

Can you draw robot configuration, a) Draw robot configuration. b) Explai...

a) Draw robot configuration. b) Explain the significance of end effectors. c) Define the terms (i) accuracy (ii) Repeatability (iii) Work volume (iv) Control Reso

Microprocessor, what is the function of CBW in the microprocessor

what is the function of CBW in the microprocessor

Determine rc and resistance, Q. A silicon npn BJT is biased by the method s...

Q. A silicon npn BJT is biased by the method shown in Figure, with R E = 240 , R 2 = 3000 , and V CC = 24 V. The operating point corresponds to V BEQ = 0.8V, I BQ = 110 µA,

Example of binary subtraction - positive number , Example  of binary  sub...

Example  of binary  subtraction - positive number Case 1.   Positive  number is more than negative number ( i e, answer is positive)   Example   subtract  4510 ( 1011012

States the superposition theorem, The superposition theorem states: 'In...

The superposition theorem states: 'In any network made up of linear resistances and having more than single source of e.m.f, the resultant current flowing in any branch is the

Energy stored in the coil, The term representing the energy stored in the c...

The term representing the energy stored in the coil may be written in terms of the inductance of the coil as... The energy stored in the coil increases with the square of t

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd