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Spectrum Sensing Using Average of Scaled Off-Diagonal Entries of a Sample Covariance Matrix for Multiantenna Cognitive Radio
- Author(s)
- AZAGE, MICHAEL DEJENE
- Advisor
- Chaewoo Lee
- Department
- 일반대학원 전자공학과
- Publisher
- The Graduate School, Ajou University
- Publication Year
- 2017-02
- Language
- eng
- Keyword
- Blind spectrum sensing; Cognitive radio; Cooperative spectrum sensing; Covariance Matrix; Multi-antenna
- Alternative Abstract
- Though in cognitive radio networks, cooperative spectrum sensing is an indispensable task that is intended for increasing spectrum utilization by accessing a licensed spectrum band or a primary user’s (PU) signal in an opportunistic manner, it is done in uncertain approach that the uncertainty is a recipe for a degradation of cognitive network users' throughput and interference to a PU’s signal. In this paper – heuristically – we devise a means for spectrum sensing for multiantenna based cognitive radio. By first dividing samples received at each antenna by their corresponding biased sample standard deviation, a sample covariance matrix (SCM) is computed. From the SCM, an average of the off-diagonal entries are used in establishing test statistics (TS), thereby enabling in formation of a TS that can combat effect of uncalibrated receivers which is a cause for differences in white noise variances. We approximated decision threshold of the TS using central limit theorem. The merit of the decision threshold of the work is that operational threshold setting at a certain desired false alarm probability does not rely on prior knowledge of noise variances. This mechanism in turn can enable in overcoming problem of noise uncertainty. Furthermore, knowledge of channel state information, and PU signal’s distribution are not needed. Correlating with our overarching goal, simulation results – which conducted at low signal to noise ratio realm– indicate that the proposed technique significantly improved performance as compared with existing methods.
- Fulltext
- Appears in Collections:
- Graduate School of Ajou University > Department of Electronic Engineering > 3. Theses(Master)
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