Recently, a new blind spectrum sensing technique based on signal space dimension estimation was developed for sensing the spectrum holes in the primary user’s bands. The mean idea of this technique is that the number of significant eigenvalues of the covariance matrix of the received signal is directly related to the presence/absence of data in the signal. In this paper, we study the collaborat...

Cognitive radio (CR) enhanced vehicular ad hoc network (CR-VANET) is a special VANET that each vehicle could explore local spectrum gap and reduce data congestion by mitigating interference by dynamically accessing spectrum holes. One of the most important challenges for CR-VANET is to identify the presence of primary users (PU) over wideband spectrum at a particular time and specific geographi...

Cognitive radio (CR) has recently been identified as a promising technology to solve the spectrum inefficiency problem. CR users or secondary users (SUs) need to sense the presence of primary users (PUs) constantly and rapidly to utilize their unused spectrum. However, detection is compromised when a user experiences shadowing or fading effects. In such cases, the user cannot distinguish betwee...

In this paper, we review some of the recent patents on spectrum sensing techniques for cognitive radio (CR) applications. The presented patents are categorized under: 1) spectrum sensing algorithms and architectures, 2) spectrum sensing and data communication and 3) cooperative spectrum sensing. The presented patents include special sensing algorithms that are based on the multi-resolution spec...

Cooperative spectrum sensing is a key function in cognitive radio networks in order to provide unused spectrum access opportunities and mitigate the impact of interference to the primary networks. Cooperative sensing can incur additional cooperation overhead, increased energy consumption, extra sensing time and delay in heterogeneous networks. In this paper, the sensing time period is optimized...

As the use of Cognitive Radio is increasing day by day, the problems related to spectrum sensing is also increasing. This paper presents a survey on different spectrum sensing methodologies. Furthermore, various sensing features like multi-dimensional spectrum sensing, cooperative sensing, dynamic spectrum access, external sensing algorithms and other alternative sensing methods are reviewed.

Multiple secondary users can cooperate to increase the reliability of spectrum sensing in cognitive radio networks. However, the total transmission power grows approximately linearly with the number of cooperative secondary users. This paper proposes a new approach to optimize the trade-off between sensing reliability and power efficiency in cooperative cognitive radio networks over fading chan...

This paper proposes an optimal cooperative spectrum sensing scheme, based on the criterion of deflection coefficient maximization of the global decision statistic. Multiple cooperative secondary users serve in the cognitive radio network to provide space diversity for spectrum sensing. After the fusion center acquires the optimal fusion weights, an optimal global threshold setting strategy is u...