Performance Analysis of Control Signal Transmission Technique for Cognitive Radios in Dynamic Spectrum Access Networks

Ren SAKATA  Tazuko TOMIOKA  Takahiro KOBAYASHI  

Publication
IEICE TRANSACTIONS on Communications   Vol.E92-B   No.12   pp.3597-3605
Publication Date: 2009/12/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E92.B.3597
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Dynamic Spectrum Access)
Category: Spectrum Allocation
Keyword: 
cognitive radio,  dynamic spectrum access,  control signal,  differential code parallel transmission,  

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Summary: 
When cognitive radio (CR) systems dynamically use the frequency band, a control signal is necessary to indicate which carrier frequencies are currently available in the network. In order to keep efficient spectrum utilization, this control signal also should be transmitted based on the channel conditions. If transmitters dynamically select carrier frequencies, receivers have to receive control signals without knowledge of their carrier frequencies. To enable such transmission and reception, this paper proposes a novel scheme called DCPT (Differential Code Parallel Transmission). With DCPT, receivers can receive low-rate information with no knowledge of the carrier frequencies. The transmitter transmits two signals whose carrier frequencies are spaced by a predefined value. The absolute values of the carrier frequencies can be varied. When the receiver acquires the DCPT signal, it multiplies the signal by a frequency-shifted version of the signal; this yields a DC component that represents the data signal which is then demodulated. The performance was evaluated by means of numerical analysis and computer simulation. We confirmed that DCPT operates successfully even under severe interference if its parameters are appropriately configured.