ICI-minimizing blind uplink time synchronization for OFDMA-based cognitive radio systems

Authors:
Ismail Güvenç;Sibel Tombaz;Mustafa E. Sahin;Hüseyin Arslan;Hakan Ali Cirpan
Affiliations:
DOCOMO Communications Laboratories USA, Inc., Palo Alto, CA;Department of Electrical Engineering, University of South Florida, Tampa, FL;Department of Electrical Engineering, University of South Florida, Tampa, FL;Department of Electrical Engineering, University of South Florida, Tampa, FL;Department of Electrical Engineering, Istanbul University, Avcilar, Istanbul, Turkey
Venue:
GLOBECOM'09 Proceedings of the 28th IEEE conference on Global telecommunications
Year:
2009

Citing 6
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Abstract

Cognitive radio is an enabling technology for efficient utilization of radio spectrum. In this paper, an orthogonal frequency division multiple access (OFDMA) based cognitive (opportunistic) network is considered, which co-exists with a macrocell network through utilizing its unused subcarriers. We particularly consider the uplink opportunity detection problem by the opportunistic network, where accurate synchronization to the macrocell network is crucial for minimizing the interference received from the macrocell users. After demonstrating the impact of synchronization on the inter-carrier-interference (ICI) observed at the opportunistic network, an improved blind first-user synchronization technique is proposed, and its statistics are analyzed. Through computer simulations it is shown that the proposed technique yields less interference and better opportunities for the opportunistic network.