Cognitive users need to detect primary users continuously and rapidly.Cooperative spectrum sensing in cognitive radio(CR) networks is analyzed.Cooperative spectrum sensing in the ideal network with two cognitive users can reduce the mean detection time.Detection probability to primary users can be improved by multi-cooperative users in multi-user networks.Finally,the realization of multi-user networks is considered.

Cooperative Spectrum Sensing in Cognitive Radio Networks

In this paper, we assess and compare the performance of French tourism destinations, using the Data Envelopment Analysis (DEA) two-stage procedure, where in the first stage the efficiency score are calculated, and then followed in the second stage by a bootstrapped truncated regression model. In the context of France such analysis takes an additional importance, especially as the country is expected to face a decrease in its tourism competitiveness. A discussion in terms of D-attraction and E-attraction is also proposed and policy recommendations are derived.

Performance of French destinations: Tourism attraction perspectives

Cooperative Spectrum Sensing

What is corporate sustainability

This paper proposes efficient cooperative cyclostationary spectrum sensing schemes in which each secondary-user (SU) performs single-cycle (SC) cyclostationary detection for fast and simple implementation, while collaboration between SUs in final decision on the presence or absence of the primary-user (PU) is explored to improve its performance. As the SUs simultaneously measure the spectral correlation functions at different cycle-frequencies (CF) and exchange their information regarding the measured results, a sufficient number of CFs are effectively examined with parallel searching, which makes the proposed cooperative spectrum sensing more reliable. This paper presents another look at performance evaluation of cyclostationary detectors in terms of deflection coefficients. Outage probability of deflection coefficient is defined as a measure to compare the performance of different cyclostationary detectors in a fading channel. Furthermore, performance of the proposed schemes in terms of false-alarm and detection probabilities is evaluated by analysis and simulation in AWGN and fading channels. Illustrative and analytical results show that the proposed schemes outperform both SC and multi-cycle (MC) cyclostationary detectors, especially in fading channels.

Efficient Cooperative Cyclostationary Spectrum Sensing in Cognitive Radios at Low SNR Regimes

Probabilistic spectrum sensing data falsification attack in cognitive radio networks

Cognitive radio (CR) is proposed to solve the spectrum scarcity problem. One of the significant issues which arises recently in CR networks is security threats. Most of the proposed methods to defend against the attacks need the previous knowledge about the system. In this study, the authors use the statistical characteristics of the users to address one of the important kinds of attacks called primary user emulation attack (PUEA). In the proposed scheme, the received power statistics of the CR users is used to detect the PUEA. The results show that their scheme has higher performance in detecting the primary transmission comparing with the previous works.

https://ietresearch.onlinelibrary.wiley.com/doi/pdf/10.1049/iet-com.2016.1248

Defence against primary user emulation attack using statistical properties of the cognitive radio received power

Molecular Communication via Diffusion (MCvD) is a promising paradigm which enables nano-machines to communicate with each other. However, the reliability of existing communication systems degrades rapidly as the distance between the transmitters and the receivers grows. To solve this issue, Decode and Forward Relaying scheme can be implemented. In this paper we study the optimal baud-rate and timing offset to mitigate the overall Inter-Symbol Interference(ISI) and obtain maximum throughput in relay network. Our simulation results indicate that relaying scheme can significantly improve the performance by 5dB at high SNRs.

Performance analysis of Decode and Forward Relay network in Diffusion based Molecular Communication

The current study proposes a new DEA model to evaluate the efficiency of 39 Chinese commercial banks over the period 2010–2018. The paper also, in the second stage, investigates the inter-relationships between efficiency and some bank-specific variables (i.e. bank profitability, bank size, expenses management, traditional business and non-traditional business) under the Robust Endogenous Neural Network Analysis. The findings suggest that the sample of Chinese banks experiences a consistent increase in the level of bank efficiency up to 2015; the efficiency score is 0.915, after which the efficiency level declines and then experiences a slight volatility, while finally ending up with an efficiency score of 0.746 by the end of 2018. We also find that among different bank ownership types, the state-owned banks have the highest efficiency, the rural commercial banks are found to be least efficient and the foreign banks experience the strongest volatility over the examined period. The second-stage analysis shows that bank size exerts a positive influence on the development of non-traditional banking business and a proactive expense management, bank size and non-traditional businesses have a positive impact on efficiency levels, while bank profitability, traditional businesses and expenses management have negative influences on bank efficiency.

/pdf/bank-efficiency-estimation-in-china-dea-renna-approach-im9dup9nri.pdf

Bank efficiency estimation in China: DEA-RENNA approach

Collaborative spectrum sensing is regarded as a key technology for tackling the challenges of the practical implementation of cognitive radio (CR). However, most of the proposed solutions require infinite bits or several bits exchanging per each CR to make the final decision to indicate the absence or presence of a primary user. It is well known that if N CRs employ energy detector with the same threshold and then send individual decision bits to a fusion centre, the OR-rule (1-out-of-N rule) will be optimal under Neyman-Pearson criterion. To decrease the average number of exchanging bits, we propose novel schemes while they perform as well as the OR-rule, our analytical and simulation results show that the proposed schemes has two important advantages over previously proposed schemes: (1) the average number of exchanging bits for N CRs always is 1/N bits per CR in perfect control channels; however, it is much higher than 1/N for the other proposed methods, e.g. it is 1 bit for the OR-rule and (2) the proposed method is very robust against the errors of imperfect control channels, specially, in low signal-to-noise ratio (SNR) regimes. Furthermore, the average number of reporting bits do not change considerably under the imperfect control channels.

Ali Jamshidi

Papers

Probabilistic spectrum sensing data falsification attack in cognitive radio networks

Defence against primary user emulation attack using statistical properties of the cognitive radio received power

Performance analysis of Decode and Forward Relay network in Diffusion based Molecular Communication

Bank efficiency estimation in China: DEA-RENNA approach

Performance analysis of low average reporting bits cognitive radio schemes in bandwidth constraint control channels