In cognitive radio, the cooperative spectrum sensing (CSS) plays a key role in determining the performance of secondary networks. However, there have not been feasible approaches that can analytically calculate the performance of CSS with regard to the multi-level quantization. In this paper, we not only show the cooperative false alarm probability and cooperative detection probability impacted...

We propose a novel paradigm for spectrum sensing in cognitive radio networks that provides diversity and capacity benefits using a single antenna at the Secondary User (SU) receiver. The proposed scheme is based on a reconfigurable antenna: an antenna that is capable of altering its radiation characteristics by changing its geometric configuration. Each configuration is designated as an antenna...

Cognitive radio has been proposed as a promising technology to resolve the spectrum scarcity problem by dynamically exploiting underutilized spectrum bands. Cognitive radio technology allows unlicensed users to exploit the spectrum vacancies at any time with no or limited extra interference at the licensed users. Usually, cognitive radios create networks in order to better identify spectrum vac...

Cognitive radio is widely expected to be the next Big Bang in wireless communications. Spectrum sensing, that is, detecting the presence of the primary users in a licensed spectrum, is a fundamental problem for cognitive radio. As a result, spectrum sensing has reborn as a very active research area in recent years despite its long history. In this paper, spectrum sensing techniques from the opt...

In cognitive radio based cooperative sensing systems, some secondary users are likely to act malicious. Such secondary users are called malicious users. An optimal application of Dixon's outlier detection scheme for detecting malicious users in a cognitive radio cooperative spectrum sensing system has recently been termed as the Sliding Window Dixon's test. The Sliding window Dixon's test appli...

As the radio spectrum is becoming more and more crowded, cognitive radio has recently become a hot research topic to improve the spectrum utilization efficiency. It is well known that the success of cognitive radio depends heavily on fast and efficient spectrum sensing that is very difficult in practice. Toward this end, this paper introduces a new guard-resident cooperative spectrum sensing sc...

Spectrum sensing is studied for multi-user cognitive radio networks in this paper. An improved spectrum sensing method----energy-cooperative detection method is developed, which combines the double threshold energy detecting method with the “OR” fusion decision rule. The simulation is done for both AWGN channel and Rayleigh channel, and the advantages of the improved method are verified.

Spectrum sensing is the most significant technique in Cognitive Radio system. So in this paper for the terrestrial television broadcasting (ISDB-T) system of integrated services digital broadcasting, i develop the algorithm based energy detector with low detection delay using sequential hypothesis testing and matched filter detector of spectrum sensing used on OFDM system which is use as a prim...

Spectrum sensing is mandatory in Cognitive Radio systems, and is used in order to identify spectrum opportunities, and to guarantee that it does not cause unacceptable interference to the license owner. Since a single sensor may be in fading or shadowing, cooperative sensing among multiple sensors which experience uncorrelated fading is required to guarantee reliable sensing performance. In thi...

This paper considers the problem of spectrum sensing in cognitive radio networks when the primary user employs Orthogonal Frequency Division Multiplexing (OFDM). We develop cooperative sequential detection algorithms based on energy detectors and the autocorrelation property of cyclic prefix (CP) used in OFDM systems and compare their performances. We show that sequential detection provides muc...