Eigenvalue Ratio Detection Based on Exact Moments of Smallest and Largest Eigenvalues

Detection based on eigenvalues of received signal covariance matrix is currently one of the most effective solution for spectrum sensing problem in cognitive radios. However, the results of these schemes always depend on asymptotic assumptions since the close-formed expression of exact eigenvalues ratio distribution is exceptionally complex to compute in practice. In this paper, non-asymptotic spectrum sensing approach to approximate the extreme eigenvalues is introduced. In this context, the Gaussian approximation approach based on exact analytical moments of extreme eigenvalues is presented. In this approach, the extreme eigenvalues are considered as dependent Gaussian random variables such that the joint probability density function (PDF) is approximated by bivariate Gaussian distribution function for any number of cooperating secondary users and received samples. In this context, the definition of Copula is cited to analyze the extent of the dependency between the extreme eigenvalues. Later, the decision threshold based on the ratio of dependent Gaussian extreme eigenvalues is derived. The performance analysis of our newly proposed approach is compared with the already published asymptotic Tracy-Widom approximation approach

Pengembangan Strategi Pembelajaran Pendidikan Agama Islam (PAI) dalam Merespon Era Digital

In today\u27s digital era, people generally think that the current learning of Islamic Religious Education (PAI) has been considered a failure to instill moral / religious values ​​to learners. This can be seen by the many crimes committed by teenagers who are students. For example; begal, drug abuse, brawl, promiscuity and other forms of crime. The failure of learning PAI, according to the author one of the reasons is because in general learning PAI done in monotonous and conventional. Therefore, as PAI educators / teachers should be innovative and creative in developing learning strategies that are interesting and fun for learners. So the values ​​of Islamic education can be well internalized in the learners. This paper comes to dissect and offer the concept of PAI learning strategies that are integrative in response to the development of technological tools in the digital era today. This paper uses the method of library research with a critical-analysis approach, thus giving birth to a concept or model of learning strategy that is integrative between religious values, science and technology

Revisiting the Electricity Consumption-Growth Nexus for Portugal: Evidence from a Multivariate Framework Analysis

The aim of present paper is to re-investigate the long-run and causal relationship between electricity consumption, income, financial development, population and foreign trade in Portugal using the bounds testing approach to cointegration within the unrestricted error-correction model (UECM). The Granger causality test within the Vector Error-Correction Model (VECM) was conducted to examine the direction of causality. This study covered the annual sample of 1971 to 2009. Our empirical evidence supports the presence of a long-run relationship between the variables in Portugal. Moreover, the results indicate that increase in real income, financial development, population and foreign trade has positive impact on electricity consumption in Portugal. In addition, the overall Granger causality results exhibit bi-directional causal relationship between electricity consumption, real income, and population while uni-directional causality is running from financial development to electricity consumption. In this respect, Portugal is an energy dependent country, thus energy conservation policy (growth policy) may adversely affect the economic growth (environment or pollution) in Portugal. Ultimately, the Portuguese government should encourage research and development on technological innovation for energy savings without affecting economic development in Portugal.Causality; electricity consumption; financial development; Portugal

Collaborative Spectrum Sensing Based on Upper Bound on Joint PDF of Exreme Eigenvalues

Detection based on eigenvalues of received signal covariance matrix is currently one of the most effective solution for spectrum sensing problem in cognitive radios. However, the results of these schemes often depend on asymptotic assumptions since the distribution of ratio of extreme eigenvalues is exceptionally mathematically complex to compute in practice. In this paper, a new approach to determine the distribution of ratio of the largest and the smallest eigenvalues is introduced to calculate the decision threshold and sense the spectrum. In this context, we derive a simple and analytically tractable expression for the distribution of the ratio of the largest and the smallest eigenvalues based on upper bound on the joint probability density function (PDF) of the largest and the smallest eigenvalues of the received covariance matrix. The performance analysis of proposed approach is compared with the empirical results. The decision threshold as a function of a given probability of false alarm is calculated to illustrate the effectiveness of the proposed approach

Energy and Spectral Efficient Inter Base Station Relaying in Cellular Systems

This paper considers a classic relay channel which consists of a source, a relay and a destination node and investigates the energy-spectral efficiency tradeoff under three different relay protocols: amplify-and-forward; decode-and-forward; and compress-and-forward. We focus on a cellular scenario where a neighbour base station can potentially act as the relay node to help on the transmissions of the source base station to its assigned mobile device. We employ a realistic power model and introduce a framework to evaluate the performance of different communication schemes for various deployments in a practical macrocell scenario. The results of this paper demonstrate that the proposed framework can be applied flexibly in practical scenarios to identify the pragmatic energy-spectral efficiency tradeoffs and choose the most appropriate scheme optimising the overall performance of inter base station relaying communications

Performance of BPSK subcarrier intensity modulation free-space optical communications using a log-normal atmospheric turbulence model

In this paper, we present simulation results for the bit error rate (BER) performance and the fading penalty of a BPSK - subcarrier intensity modulation (BPSK-SIM) free-space optical (FSO) communication link in a log-normal atmospheric turbulence model. The results obtained are based on the Monte-Carlo simulation. Multiple subcarrier modulation schemes offer increased system throughput and require no knowledge of the channel fading in deciding what symbol has been received. In an atmospheric channel with a fading strength 2 l ? of 0.1 obtaining a BER of 10-6 using a 2-subcarrier system will require a signal-tonoise (SNR) of 23.1 dB. The required SNR increases with the fading strength and at a BER of 10-9 the fading penalty due to the atmospheric turbulence is ~ 41 dB for 9 . 0 2 = l ? . The comparative studies of the OOK and BPSK-SIM schemes showed that for similar electrical SNR, BPSK-SIM offered improved performance across all range of turbulence variance