MEASUREMENT BASED INVESTIGATON OF CYCLOSTATİONARITY OF OFDM SIGNALS

Year 2017, Volume: 17 Issue: 2, 3327 - 3334, 27.07.2017

Kürşat Tekbıyık Hakan Alakoca Halim Bahadır Tuğrel Cem Ayyıldız Güneş Karabulut Kurt

Abstract

Increasing need for efficient
usage of frequency spectrum causes to search new methods. Network operators are
forced to use their frequency band as efficient as possible due to high
subscriber demand. Blind recognition of unauthorized users became necessary to
obtain efficient usage of frequency bands. It is  found that the two different OFDMA signals
with the same CP length show different cyclostationary characteristics. In this paper, it is shown that it is possible that signals from two
different users with the same CP lengths can be separated from each other via mesurementS
results. Moreover, cyclic autocorrelation function and spectral correlation
density function are computed for each user. The differences between their
cyclic properties are shown by software defined radio measurement results. It
is shown that signals transmitted from specific users can be detected by using
cyclic autocorrelation and spectral density functions characteristics. 

Keywords

OFDMA, cylostationarity, blind reconition

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