• Journal of KIISE:Information Networking
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• v.37 no.3
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• pp.249-253
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• 2010

Resource of wireless frequency bandwidth is gradually going to be deficient due to explosive increase of traffic and saturated non-licensed frequency band such as ISM. In the contrary, many licensed frequency bands are revealed to be low in utilization by several measurement based researches. To alleviate this inefficiency, a concept of cognitive radio is suggested. Cognitive radio lets non-licensed user exploit the licensed frequency band as long as non-licensed user does not interfere licensed user and as a result, it is possible to harness wireless frequency more efficiently. IEEE 802.22 is the first standard network with cognitive radio technology and it employs Two-Stage channel sensing mechanism to accomplish both enough licensed user protection and efficient channel utilization. In this paper, we analyze the overhead of Two-Stage channel sensing mechanism and identify the influence of channel sensing time to the overhead.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.12
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• pp.1739-1741
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• 2016

A compressive sensing based iterative scheme for reducing both the impulsive noise as well as the clipping noise is proposed for OFDM-based communication systems. Nonlinear blanking using adaptive thresholds is used in the 1st stage followed by two consecutive compressive sensing based detection with the aid of decision feedback for reducing the BER gradually. Our simulation results revealed an SNR gain of 4.5dB at the BER of $10^{-5}$.