16-04-2012, 02:25 PM
PERFORMANCE ANALYSIS OF UNDERLAY
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Problem Statement
Cognitive radio faces adverse problem in communication due to primary user so that primary will not get affected.
To enhance the performance of underlay/overlay waveform in cognitive radio.
Determine the optimum modulation technique and parameters.
What is MC-CDMA
A combination of OFDM and CDMA
A form of Direct Sequence CDMA, but after spreading a Fourier Transform (FFT) is performed.
A form of Orthogonal Frequency Division Multiplexing (OFDM), but with an orthogonal matrix operation on the bits.
A form of frequency diversity. Each bit is transmitted simultaneously (in parallel) on many different subcarriers.
Conclusion
In awgn/frequency fading channel as we increase the number of subcarrier the performance of the system increases.
And as the primary user increases in the channel bandwidth the underlay system performance decreases