[KSCI] Korea Science Citation Index Service

http://dx.doi.org/10.4218/etrij.14.0113.0758

Sensing of OFDM Signals in Cognitive Radio Systems with Time Domain Cross-Correlation

Xu, Weiyang (College of Communication Engineering, Chongqing University)

Publication Information

ETRI Journal / v.36, no.4, 2014 , pp. 545-553 More about this Journal

Abstract

This paper proposes an algorithm to sense orthogonal frequency-division multiplexing (OFDM) signals in cognitive radio (CR) systems. The basic idea behind this study is when a primary user is occupying a wireless channel, the covariance matrix is non-diagonal because of the time domain cross-correlation of the cyclic prefix (CP). In light of this property, a new decision metric that measures the power of the data found on two minor diagonals in the covariance matrix related to the CP is introduced. The impact of synchronization errors on the signal detection is analyzed. Besides this, a likelihood-ratio test is proposed according to the Neyman-Pearson criterion after deriving probability distribution functions of the decision metric under hypotheses of signal presence and absence. A threshold, subject to the requirement of probability of false alarm, is derived; also the probabilities of detection and false alarm are computed accordingly. Finally, numerical simulations are conducted to demonstrate the effectiveness of the proposed algorithm.

Keywords

OFDM; cyclic prefix; covariance matrix; signal detection; Neyman-Pearson criterion;

Citations & Related Records

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