16-07-2012, 01:07 PM
CHANNEL EQUALISATION and ber calculation
[attachment=27724]
INTRODUCTION
Wireless communication systems require signal processing techniques that improve link performance.
As channel is dynamic due to multipath propagation and Doppler spread.
These impairments cause the signal to distort or fade significantly.
Channel equalization
Channel equalisation is the process of compensating for the effect of the physical channel between a transmitter and a receiver.
Communication channels are susceptible to intersymbol interference (ISI).
Without channel equalisation, the utilisation of the channel bandwidth becomes inefficient.
Reason for adaptive equalizer
The objective of adaptive equalizer is to adapt the coefficients to minimize the noise and intersymbol interference (depending on the type of equalizer) at the output.
The adaptation of the equalizer is driven by an error signal.
Adaptive equalizer
If the channel is frequency selective, the equalizer enhances the frequency components with small amplitudes and attenuates the strong frequencies in the received frequency response
For a time-varying channel, an adaptive equalizer is needed to track the channel variations.
[attachment=27724]
INTRODUCTION
Wireless communication systems require signal processing techniques that improve link performance.
As channel is dynamic due to multipath propagation and Doppler spread.
These impairments cause the signal to distort or fade significantly.
Channel equalization
Channel equalisation is the process of compensating for the effect of the physical channel between a transmitter and a receiver.
Communication channels are susceptible to intersymbol interference (ISI).
Without channel equalisation, the utilisation of the channel bandwidth becomes inefficient.
Reason for adaptive equalizer
The objective of adaptive equalizer is to adapt the coefficients to minimize the noise and intersymbol interference (depending on the type of equalizer) at the output.
The adaptation of the equalizer is driven by an error signal.
Adaptive equalizer
If the channel is frequency selective, the equalizer enhances the frequency components with small amplitudes and attenuates the strong frequencies in the received frequency response
For a time-varying channel, an adaptive equalizer is needed to track the channel variations.