Silence Reporting for Cooperative Sensing in Cognitive Radio Networks

Do-Yun Kim,Young-June Choi,Jeung Won Choi 한국인터넷방송통신학회 2018 International Journal of Internet, Broadcasting an Vol.10 No.3

A cooperative spectrum sensing has been proposed to improve the sensing performance in cognitive radio (CR) network. However, cooperative sensing causes additional overhead for reporting the result of local sensing to the fusion center. In this paper, we propose a technique to reduce the overhead of data transmission of cooperative sensing for applying the quantum data fusion technique in cognitive radio networks by omitting the lowest quantized in the local sensed results. If a CR node senses the lowest quantized level, it will not send its local sensing data in the corresponding sensing period. The fusion center can implcitly know that a spectific CR node sensed lowest level if there is no report from that CR node. The goal of proposed sensing policy is to reduce the overhead of quantized data fusion scheme for cooperative sensing. Also, our scheme can be adapted to all quantized data fusion schemes because it only deal with the form of the quantized data report. The experimental results show that the proposed scheme improves performance in terms of reporting overhead.

Opportunistic Reporting-based Sensing-Reporting-Throughput Optimization Scheme for Cooperative Cognitive Radio Networks

( Jaewoo So ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.3

This paper proposes an opportunistic reporting-based sensing-reporting-throughput optimization scheme that maximizes the spectral efficiency of secondary users (SUs) in cooperative cognitive radio networks with a soft combining rule. The performance of cooperative spectrum sensing depends on the sensing time, the reporting time of transmitting sensing results, and the fusion scheme. While longer sensing time and reporting time improve the sensing performance, this shortens the allowable data transmission time, which in turn degrades the spectral efficiency of SUs. The proposed scheme adopts an opportunistic reporting scheme to restrain the reporting overhead and it jointly controls the sensing-reporting overhead in order to increase the spectral efficiency of SUs. We show that there is a trade-off between the spectral efficiency of SUs and the overheads of cooperative spectrum sensing. The numerical results demonstrate that the proposed scheme significantly outperforms the conventional sensing-throughput optimization schemes when there are many SUs. Moreover, the numerical results show that the sensing-reporting time should be jointly optimized in order to maximize the spectral efficiency of SUs.

Unlimited Cooperative Sensing with Energy Detection for Cognitive Radio

Bae, Sunghwan,Kim, Hongseok The Korea Institute of Information and Commucation 2014 Journal of communications and networks Vol.16 No.2

In this paper, we investigate the fundamental performance limits of the cooperative sensing using energy detection by considering the unlimited number of sensing nodes. Although a lot of cognitive radio research so far proposed various uses of energy detection because of its simplicity, the performance limits of energy detection have not been studied when a large number of sensing nodes exist. First, we show that when the sensing nodes see the independent and identically distributed channel conditions, then as the number of sensing nodes N goes to infinity, the OR rule of hard decision achieves zero of false alarm Pf for any given target probability of detection $\bar{P_d}$ irrespective of the non-zero received primary user signal to noise ratio ${\gamma}$. Second, we show that under the same condition, when the AND rule of hard decision is used, there exists a lower bound of $P_f$. Interestingly, however, for given $\bar{P_d}$, $P_f$ goes to 1 as N goes to infinity. Third, we show that when the soft decision is used, there exists a way of achieving 100% utilization of secondary user, i.e., the sensing time overhead ratio goes to zero so does $P_f$.We verify our analyses by performing extensive simulations of the proposed unlimited cooperative sensing. Finally, we suggest a way of incorporating the unlimited cooperative sensing into a practical cellular system such as long term evolutionadvanced by exploiting the existing frame structure of absolute blank subframe to implement the in-band sensing.

Asynchronous Cooperative Spectrum Sensing Scheme on Primary Users with Fast “On/Off” State Variations in Spectrum Sensing Windows

Jingying Jin(김정영),Junrong Gu(구준룡),Jae Moung Kim(김재명) 한국통신학회 2013 韓國通信學會論文誌 Vol.25 No.8

Cognitive Radio has attracted intensive interests of the researchers, recently. The data rate always increases in the emerging technologies. The increased data rate poses mainly two challenges for spectrum sensing. One is that the state of primary user (PU) is fast and alternatively varying between “on/off” in a spectrum sensing window. The other is that the asynchronicity among the reports in a cooperative spectrum sensing setting becomes more apparent. Both of them would deteriorate the spectrum sensing performance. Thus, we propose an asynchronous cooperative spectrum sensing method to cope with these two challenges. A likelihood ratio test based spectrum sensing is developed for a single cooperator. The likelihood ratio is obtained in the setting of fast varying PU state. The likelihood ratio test is uniformly powerful according to the Neyman-pearson lemma. Furthermore, the asynchronicity among the cooperators are studied. Two sets of fusion weights are discussed for the asynchronous time among cooperators. One is designed based on the condition probability of the PU state variation and the other one is designed based on the queueing theory. The simulation results are provided with different fusion methods. The performance improvements are demonstrated.

Silence Reporting for Cooperative Sensing in Cognitive Radio Networks

Kim, Do-Yun,Choi, Young-June,Choi, Jeung Won The Institute of Internet 2018 International Journal of Internet, Broadcasting an Vol.10 No.3

A cooperative spectrum sensing has been proposed to improve the sensing performance in cognitive radio (CR) network. However, cooperative sensing causes additional overhead for reporting the result of local sensing to the fusion center. In this paper, we propose a technique to reduce the overhead of data transmission of cooperative sensing for applying the quantum data fusion technique in cognitive radio networks by omitting the lowest quantized in the local sensed results. If a CR node senses the lowest quantized level, it will not send its local sensing data in the corresponding sensing period. The fusion center can implcitly know that a spectific CR node sensed lowest level if there is no report from that CR node. The goal of proposed sensing policy is to reduce the overhead of quantized data fusion scheme for cooperative sensing. Also, our scheme can be adapted to all quantized data fusion schemes because it only deal with the form of the quantized data report. The experimental results show that the proposed scheme improves performance in terms of reporting overhead.

Social Incentives for Cooperative Spectrum Sensing in Distributed Cognitive Radio Networks

( Jingyu Feng ),( Guangyue Lu ),( Xiangcen Min ) 한국인터넷정보학회 2014 KSII Transactions on Internet and Information Syst Vol.8 No.2

Cooperative spectrum sensing has been considered as a promising approach to improve the sensing performance in distributed cognitive radio networks. However, there may exist some selfish secondary users (SUs) who are unwilling to cooperate. The presence of selfish SUs could cause catastrophic damage to the performance of cooperative spectrum sensing. Following the social perspective, we propose a Social Tie-based Incentive Scheme (STIS) to deal with the selfish problem for cooperative spectrum sensing in distributed cognitive radio networks. This scheme inspires SUs to contribute sensing information for the SUs who have social tie but not others, and such willingness varies with the strength of social tie value. The evaluation of each SU`s social tie derives from its contribution for others. Finally, simulation results validate the effectiveness of the proposed scheme.

Unlimited Cooperative Sensing with Energy Detection for Cognitive Radio

배성환,김홍석 한국통신학회 2014 Journal of communications and networks Vol.16 No.2

In this paper, we investigate the fundamental performancelimits of the cooperative sensing using energy detection byconsidering the unlimited number of sensing nodes. Although a lotof cognitive radio research so far proposed various uses of energydetection because of its simplicity, the performance limits of energydetection have not been studied when a large number of sensingnodes exist. First, we show that when the sensing nodes see theindependent and identically distributed channel conditions, thenas the number of sensing nodes N goes to infinity, the OR rule ofhard decision achieves zero of false alarm Pf for any given targetprobability of detection Pd irrespective of the non-zero receivedprimary user signal to noise ratio. Second, we show that underthe same condition, when the AND rule of hard decision is used,there exists a lower bound of Pf . Interestingly, however, for givenPd, Pf goes to 1 as N goes to infinity. Third, we show that whenthe soft decision is used, there exists a way of achieving 100% utilizationof secondary user, i.e., the sensing time overhead ratio goesto zero so does Pf .We verify our analyses by performing extensivesimulations of the proposed unlimited cooperative sensing. Finally,we suggest a way of incorporating the unlimited cooperative sensinginto a practical cellular system such as long term evolutionadvancedby exploiting the existing frame structure of absoluteblank subframe to implement the in-band sensing.

A Cooperative Spectrum Sensing Scheme with an Adaptive Energy Threshold in Cognitive Radios

Van, Hiep-Vu,Koo, In-Soo The Korea Institute of Information and Commucation 2011 Journal of information and communication convergen Vol.9 No.4

Cognitive radio (CR) technique is a useful tool for improving spectrum utilization by detecting and using the vacant frequency bands while avoiding interference to the primary user. The sensing performance in a CR network can be improved by allowing some CR users to perform cooperative spectrum sensing. In this paper, we propose a new sensing algorithm that utilizes an adaptive energy threshold for cooperative spectrum sensing in which a changeable energy threshold is adopted by the CR users for improving local sensing performance. Through the proposed scheme, the reliability of global decision can be enhanced mainly due to the improvement in local sensing performance.

A cooperative spectrum sensing scheme using adaptive fuzzy system for cognitive radio networks

Kieu-Xuan, T.,Koo, I. North-Holland [etc ; Elsevier Science Ltd 2013 Information sciences Vol.220 No.-

Cognitive radio represents a promising design paradigm for the next-generation of wireless networks that can enhance utilization of the scarce spectrum available. It allows dynamic spectrum access over temporarily unused spectrum holes that are identified by spectrum sensing. In order to enhance the sensing accuracy by taking advantage of the spatial diversity in multiple cognitive radio user networks, cooperative spectrum sensing has been proposed in the literature. However, most existing cooperative spectrum sensing schemes require knowledge of the noise variance and signal-to-noise ratio of primary signal at each node, which can add a significant transmission overhead. This paper proposes an adaptive fuzzy system-based scheme for cooperative spectrum sensing without the need for a priori network information such as the noise variance, channel state information, and characteristics of existing primary signals. Energy observations at nodes are used for online learning from the environment to make a reliable global sensing decision at a central node without further information. Simulation results show that the proposed scheme outperforms the equal-gain combination based scheme, and matches the optimal soft combination scheme in terms of sensing accuracy.

An Enhanced Cooperative Spectrum Sensing with Wavelet Denoising and Softened Hard Decision for Cognitive Radio Networks

G. Padmavathi,S. Shanmugavel 보안공학연구지원센터 2014 International Journal of Future Generation Communi Vol.7 No.6

Cognitive Radio (CR) is a novel technology that can improve the utilization efficiency of the radio spectrum and also address the spectrum scarcity problem by opportunistically using the unused channels (spectrum holes / white spaces) in the Licensed Spectrum of Primary Users. Spectrum sensing is the primary function of CR which determines the spectrum holes for opportunistic usage by Secondary Users. Spectrum sensing plays a critical role in Cognitive Radio. The development of a reliable and accurate spectrum sensing is very essential to propound quick and accurate detection of white spaces for better throughput of Secondary User network under the constraint of the specified Primary System protection. In this paper, a Cooperative Spectrum Sensing using Wavelet Denoising along with Soften Hard Decision technique has been proposed to improve the performance of spectrum sensing. Simulation result shows an improvement of nearly 15% in the Probability of Missed Detection for a target Probability of False Alarm of 0.1 and SNR of -10 dB. Also 50% improvement in error probability has been achieved with 1-D one level wavelet denoising.